James' World

This blog post contains my notes for advanced users (Mac OS software developers and IT staff), not end-users.

Starting with Mac OS X El Capitan (10.11), some low-level system operations, like setting the NVRAM, are restricted by default by System Integrity Protection (SIP), which is controlled by the csrutil command.

However, the csrutil disable (or enable) command can only be run in a terminal after booting into a recovery OS partition (officially) or an installer (works for me, see below.)

Machines with a cloned OS often don’t have a recovery partition, or if they do, it doesn’t show up in the Startup Manager interfaces.

Even when there is a hidden recovery OS partition, versions of software starting with El Capitan have removed the Disk Util menu option to enable the recovery OS partition with Debug (apparently to hide the EFI partitions) when hidden. (Leave a note if you’ve used an older version of Diskutil to enable it. 🙂 )

You have 5 options of varying difficulty to choose from if you don’t want to do a full re-install of Mac OS X:

1) not that ez – install (ie. fix) your recovery partition, as recommended in most Internet How-to’s. Good luck, since most of the How to’s are incoherent. A suggestion would be to find one that talks only about one OS, preferably yours, instead of 4 or 5 versions.
2) ez – boot into a USB Mac OS El Capitan (or higher) installer, but don’t install. Just open the OS X Utilities ... Terminal menu and try csrutil disable. This worked for me, but if not, #5 below also worked for me.
3) didn’t try – install the recover partition to an external drive. My understanding is that this is intended for the Mac mini. Supposed to be ez.
4) didn’t try – try booting into a Lion installer and use the old Diskutil with debug mode to enable the hidden recovery HD partition. If you want to try that, boot into a Lion installer then open Terminal and type the following command, then open Diskutil last:

$ defaults write com.apple.DiskUtility DUDebugMenuEnabled 1​

5) super ez – boot into a USB installer, use Utilities … Diskutil … resize your original drive for a new 25 GB OS partition and install to it. Since you’re doing a fresh install, a recovery hd partition will be automatically created. boot into that with Option+R and run csrutil disable and reboot again to activate. This sounds kind of round-about, but is really easy, idiot-proof, and worked for me.

You’ll end up with something like this:

$ diskutil list
/dev/disk0 (internal, physical):
#:                  TYPE NAME         SIZE     IDENTIFIER
0: GUID_partition_scheme             *500.1 GB disk0
1:                   EFI EFI          209.7 MB disk0s1
2:             Apple_HFS HardDisk     474.6 GB disk0s2
3:            Apple_Boot Recovery HD  650.0 MB disk0s3 # can't see
4:             Apple_HFS Untitled      24.0 GB disk0s4
5:            Apple_Boot Recovery HD  650.0 MB disk0s5 # from option #5

$ csrutil disable
Successfully disabled System Integrity Protection. Please restart the machine for the changes to take effect.
$ csrutil status
System Integrity Protection status: disabled.

Of course, when you’re done, run csrutil enable because that’s the default, and it protects the NVRAM from malware.

Terminology: “recovery OS partition” and “recovery HD partition” refer to the same thing, but the first is conceptual and the second is an actual disk partition intended for recovery and contains the recovery OS.

Also “Disk Util” is the Mac OS app, “Diskutil” is the on-boot menu option and “diskutil” is the CLI program. Again, the names vary but they all do the same thing, but available in different environments.

developer.apple.com: Configuring System Integrity Protection
W: System Integrity Protection

I’ve read about possible helium shortages for years, but this is the first time I’ve heard of actual impact.

Helium is a strategically important element used in MRI machines and scientific experiments. It’s so light, that if you don’t store it in a cylinder, it escapes into outer space.

Making it (transmutation) is too expensive for commercial use, so it has to be captured from decay. Hence using it in party balloons is short-sighted.

Interesting that balloon purchases make Party City Amazon-proof. 🙂

Dollar Tree also does a roaring business in the Bay Area for birthday party balloons.

cnn.com: Party City is facing a helium shortage. It’s also closing 45 stores HN
forbes.com: Why We Are Running Out of Helium And What We Can Do About It

While on vacation in Las Vegas last week, I saw the record rainfall. I had just entered the hotel, and noticed blackening cumulonimbus clouds over the hills – within 30 minutes torrential rains lashed the hotel windows.

Ultimately a record 0.25 to 1 inch of rain and hail fell.

Torrential rain and hail arriving in Las Vegas. The sky view from downtown Las Vegas was almost all black.

I booked the tour through Grayline Tours, and saw the following:

1. Ethel M/Mars Chocolate Factory and Botanical Cactus Gardens
2. Lake Mead “Desert Princess” boat tour
3. Hoover Dam tour inside (conduits and generators)
4. Hoover Dam tour from top

The Hoover Dam took 5,000 workers and 5 years to build in the middle of the Depression.

It was the largest construction in history at the time, and still looks like it was built yesterday.

The dam was built primarily for water resource management, with the electrical generation a bonus. The electrical production paid off the dam project by 1986.

Hoover Dam – view from “Desert Princess” boat on Lake Mead

Hoover Dam – 7×130 MW Generators (~1 GW per side totaling 2 GW, supplying half of region’s electrical needs)

Hoover Dam – view from top of dam towards Colorado River showing concrete bridge, which took 9 years to build

W: Hoover Dam

One of my TuCows/Hover.com domain names became unresolvable recently that was DNS hosted with servermatrix.com.

So it appears IBM Cloud/Softlayer/ServerMatrix may be doing some zone cleanup in 2019, and you should want to double-check any domain names hosted there. Or better yet, add monitoring.

TuCows/Hover.com chat support was very helpful in determining the problem and resolving it. Bad pun, ya? 🙂

From time to time, people ask me how to get started in the career of computer programming.

If you like solving puzzles and have the ability to focus for hours at a time, then you’re a good candidate to enjoy a programming career. Many programmers are introverts, so if that describes you, great! 🙂

First ask your friends, co-workers or hosting provider which computer language they use. If they don’t have an opinion, read on.

For writing scripts (small programs), the 3 main languages are:

Perl has some advantages in that older sample scripts were usually written in Perl, and it’s an extremely powerful and compact language. Perl is popular with people who want the biggest hammer available for solving problems, or who want to specialize in security engineering scripting. 🙂

On job sites, Python is currently the most popular scripting language. It also has good Machine Learning support. Python is popular with people who have OCD or like to “follow the rules” with its indentation rules. Google uses python or Java for most programming.

PHP is popular with people who mostly want to do web programming, and has the widest hosting provider (ISP) support. Besides WordPress, Facebook also uses PHP.

After learning simple programming, build a web site for a CD collection inventory to learn basic HTML, CSS and database programming with MySQL.

Southwest Airlines Boeing 737 MAX8 Parking Lot at Chicago Midway Airport (MDW)

• Fukushima
• p-hacking in the social sciences
• SF Transbay Terminal welding and materials failures
• Bitcoin speculation
• and now Boeing MCAS.

So, let me get this straight about the Boeing 737 MAX MCAS sensors:

1. MCAS is non-redundant – it relies on only one of two fuselage-mounted external Angle-of-Attack (AoA) sensors to control the most critical flight control, the stabilizer
2. that can be damaged or frozen
3. the 2 sensors can disagree with no warning to the pilot (except with a warning light in an optional package and compatible display device, which even Southwest initially didn’t have)
4. that are not checked for zero on the ground
5. and fuselage-mounted AoA sensors don’t provide true AoA except when wings-level
6. behavior doesn’t match the certification documents, and no training materials provided.

The Angle-of-attack (AoA) sensor is located near the bottom of the foto. Note that it is exposed to physical damage and icing.

and …

1. MCAS is activated on manual flight, where the pilot wouldn’t expect to have to disengage any “autopilots”. (But they would know what a stickshaker warning is.)
2. MCAS is activated on flaps-up, thus immediately after takeoff, with little time for correction. Knowing how to disable MCAS would have to be a memory item, since reading the flight manual or checklist could easily take longer than the 25 seconds MCAS needs to hit the stop and become unrecoverable at low altitude (and in fact, one of the pilots was reading the flight manual at the time of impact.)
3. MCAS can trim the stabilizer full nose-down to the stop (5 degrees) instead of the original FAA-approved 0.6 degrees, and will continuously to do so with a failed sensor like some kind of doomsday machine.

And this wasn’t adequately documented before revenue flying on the most popular airliner ever sold?

What’s interesting is that had a faithful simulator been created, this problem would have been found much earlier. But that would have raised re-certification and training questions.

MCAS was a bad proof-of-concept system, not at all ready for airline use. I can’t believe that not a single Boeing engineer noticed this design error.

Kudos to the crew of the first Lionair incident flight. The 3 pilots exercised good CRM and found the cutout switches in time to save their plane. (I recommended 3-man crewing for SE Asian flights in a previous post.)

“The FAA said it will mandate Boeing’s software fix in an airworthiness directive no later than April.” – but how does that fix the non-redundant sensor?

flyingmag.com: Lion Air Investigation Takes an Unexpected Turn
b737.org.uk: 737 MAX – MCAS
seattletimes.com: Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system
theaircurrent.com: The World Pulls the Andon Cord on the 737 MAX
Capt. Sullenberger on the FAA and Boeing: ‘Our credibility as leaders in aviation is being damaged’
The emerging 737 MAX scandal, explained
737: The MAX Mess (Very detailed notes)
American Airlines extends Boeing 737 Max flight cancellations
avweb.com: International Committee To Review MAX
avweb.com: Will Boeing Ever Dig Itself Out?

Interesting how supposedly “obsolete” but great military airplanes never disappear:

• USA has chosen the B-52 (first flown 1952) to outlast the B-1 and B-2 due to high maintenance costs and low dispatch rate of the newer stealth bombers. More.
• USA relies on the F-5/T-38 (first flown 1959) for a large percent of its “behind-the-scenes” training and testing military operations. So much so that Cold War Military Assistance Program (MAP) versions are being repatriated from overseas and overhauled for drone use.

  NASA’s forward-swept X-29 (2 copies) were an F-5 body with F-16 landing gear. Unfortunately the wings on one of the pair were cut with a titanium chainsaw to truck to an East Coast museum instead of via the Panama Canal or ferrying, so it won’t fly again.

  
  
  X-29 #049. Notice tufting on the wing surface, aft fuselage and aft control surfaces to visualize airflow, which is expected to flow from wingtip to inboard for a forward-swept wing. Each of the parties that funded the research is listed on the side.
  
  Swiss Air Force F-5E. USA is buying back 22 plus spares for Top Gun and other programs in 2019!
  
  “Perhaps the most interesting aviation item in the FY20 request is that for 22 Northrop F-5E/F Tiger II aircraft, to be divided equally between the Navy and Marine Corps. These aircraft will be acquired to improve and expand the adversary fleets of both services. The Navy bought 44 F-5E/Fs from Switzerland in the 2000s, refurbishing them as F-5Ns. The new batch of 22 is also coming from Switzerland, and the aircraft are due for refurbishment by Northrop Grumman at its St Augustine, Florida, facility. The value of this requested purchase is just under $40 million for all 22 aircraft and spares.”

• India lost a MiG-21 (first flown 1959) in the Kashmir air battle in Feb. 2019
• India is buying more MiG-29s (first flown 1977) for $40 million each

What those planes all have in common is that they had all-metal airframes that required low maintenance – none are fly by wire or composite (Mig 29 has minimal composites.) The fighters can all land on grass strips and be maintained without a hangar or special tools.

nytimes.com: After India Loses Dogfight to Pakistan, Questions Arise About Its ‘Vintage’ Military
reuters.com: Washington wants to know if Pakistan used U.S.-built jets to down Indian warplane
ainonline.com: India Requests Additional MiG-29 Fighters
Pentagon To Retire USS Truman Early, Shrinking Carrier Fleet To 10
Did Pakistan use its Chinese JF-17 jets to shoot down Indian planes?
Fighting Falcon puts off retirement: F-16 to fly for USAF through 2048
Dutch F-16 flies into its own bullets, scores self-inflicted hits
avweb.com: Sometimes Old Technology Is Appropriate
avweb.com: Honeywell Retires Convair 580 after 67 years (mfg. 1952, same as B-52)

W: MiG-21, MiG-29, F-5, B-52, Convair 580

35 Hard Truths You Should Know Before Becoming “Successful” is a comprehensive and well-written collection of life and business development topics.

They can be used in many useful ways:

1. read in one sitting, combined with self-reflection
2. as a sequence of items to study, one per day
3. as topics to expand upon, for example, google each of the quotes and examples for more details
4. as topics to discuss between mentor and mentee
5. even if some are intuitive, it’s good to explore them deeper.

My favorites are 12, 16, 18 and 20.

How to be More Productive and Eliminate Time Wasting Activities by Using the “Eisenhower Box”
W: Koan
What I Learned From Learning How to Say No
Example of Compliment Sandwich Letter
“Be yourself” is terrible advice HN

Suggestions:

• “Ask yourself periodically, is this who I really wanna be?”
• “Just do it.”
• “Be the best version of yourself you can possibly be.”
• “Become your Platonic ideal.”

We Don’t Have Unprofitable Customers, Just Unhappy Accidents HN
“TL;DR for folks without sales lingo:

Companies often think their business would be healthier if they got rid of their “bad customers,” but a customer who is difficult with one provider (e.g. always asks for discounts, doesn’t commit over time) can act much more nicely with providers who they consider critical to their business. This is evidenced through a merger where two distribution companies compare customer lists and realize that one’s best customer is the other’s worst — in other words, a customer isn’t good or bad, they just behave differently with different suppliers. So the key to business is not to get rid of the bad customers, but to become your customers’ favorite supplier so that they build a long-term partnership with you.”

Okabashi: Footwear Company Makes 1.2 Million Shoes a Year in Georgia

getpocket.com: Why You Can’t Trust Yourself
Every productivity thought I’ve ever had, as concisely as possible

I watched Super Bowl LIII on TV.

The New England Patriots won over the Los Angeles Rams 13-3.

Low-scoring first half, but it picked up in the 4th quarter. Still ended up being the lowest scoring game in history.

Some ugly plays, with one player apparently spearing a receiver in the back near the ground (might have been unintentional), and another reaching into the mask of an opponent.

Final field goal was a miss.

Edelman was MVP.

Tom Brady’s 6th ring at 36 years old – representing middle-agers. 🙂

Colbert’s gloating over a “free commercial spot” was the funniest ad.

W: Super Bowl LIII
Bob Costas, unplugged: From NBC and broadcast icon to dropped from the Super Bowl

Rare snow rollers spotted in field near Marlborough

Imagine your whole country’s Internet going dark. Kudos to the private ISP owners in Tonga who financed and organized a solution while the fiber is repaired.

Bali is another island in a similar situation, at 100% electrical and Internet capacity (excluding the private Biznet Fiber link from Jakarta) for over a decade. Restrictive proxying and timeouts are used to control bandwidth usage, along with “USB drive sneaker net”, similar to Cuba.

When there’s a fiber cut, you just spend the week or two at the beach until it’s fixed. 🙂

Geek heroes rescue Tonga from worst case fibre optic cable blackout

Great photo collection of Burt Rutan-designed planes by Flying Magazine.

He favored composites since he could mfg. prototypes almost 10x faster than metal or wood.

Northrop Grumman bought his company, Scaled Composites. This is his Firebird H03 Observation plane.

Rutan Model 401 (Photo 2019)

(SpaceX just replaced carbon fiber with stainless steel in their “Starship” vehicle for that reason. I’m not sure how they went down that blind alley, in 2018 no less.)

One of the prototypes is the Stratolaunch, the world’s largest airplane:

Stratolaunch satellite launch plane (Photo 2019)

One of the nice things about composites is that they’re hail-resistant (small hailstones just rebound) unlike painted aluminum. However, it takes discipline to realize weight savings over metal for structural-related components, and long-term maintenance of composites is still an open question.

yt: Turbofan Killer Bee: Rutan ARES “Mudfighter” for U.S. Army Close Air Support

W: Burt Rutan, Stratolaunch
Composites: Tips for working on Cirrus composite structures
A Hailstorm Completely Obliterated This American Airlines Plane
Preparing for hail season
avweb.com: ‘Secret’ Model 401 Airplane Stops At FBO
thedrive.com: Scaled Composites’ Stealthy Mystery Jet Is Now At The Navy’s Top Flight Test Base
In California, giant Stratolaunch jet flies for first time HN
The world’s largest airplane is up for sale for $400 million
avweb.com: Stratolaunch Price Tag $400,000,000

Thanks to funding and project management by CERN, KiCad is the most advanced free EDA tool now.

CERN has funded differential traces, and dragging.

Free tools will likely never catch up to commercial tools for parts libraries and integration with other tools.

But KiCAD gives many users a viable long-term path for creating PCBs that they can still update years from now without Cloud fees a la Eagle (recently bought by Autodesk.)

Lessons from Running a Small-Scale Electronics Factory in my Guest Bedroom, part 1: Design HN
Exclave: Hardware Testing in Mass Production, Made Easier

madengr: “I had an electronic module that worked in our lab, but failed at the customers, but then worked again in ours.

Turns out one of the pins in a space grade connector (MDM-25) open-circuited exactly between 68F and 70F. Our lab was 70F, and the customers was 69F. The way we caught it was to be watching the temp chamber when it slowly ramped from cold to ambient.

Turns out the connector supplier had shifted production to Mexico, and they were contaminating the contacts with RTV when sealing it. ”

Skewed Layout
cern.ch: KiCad development Bugs
Seeed Studio guide to DFM
Xilinx: 7 Series FPGAs PCB Design Guide
Soldering SMD LED diodes
Electronics and electrical design checklist
High Power Circuit Board Design (PCB) – KiCad 5 – Part 1

Avweb has an article mentioning EMAS: “Southwest Airlines Flight 278 slid off the end of the runway while landing at California’s Hollywood Burbank Airport (BUR) at 9:05 am local time on Thursday. According to a statement issued by the FAA, the Boeing 737 came to rest in the Engineered Material Arresting System (EMAS) at the end of Runway 8. No injuries …”

Note the crushed “bricks” near the nose wheel – that’s EMAS

EMAS is used in the USA when there is less than 1000′ of suitable overrun for a runway. As the “bricks” get crushed, speed is dissipated. Of the 13 reported incidents, half have been airliners and half GA or cargo planes.

I’m interested in finding out:

1. how much it costs to remediate the EMAS
2. how the pax got back to the terminal
3. how the plane got free of the EMAS since it can’t taxi
4. did the engines ingest EMAS?
5. were the landing gear or doors damaged by EMAS?

faa.gov: Fact Sheet – Engineered Material Arresting System (EMAS)

Informative video on deploying Dart pop-out floats on a Robinson R66 helicopter, then repacking them.

Takes about 8 seconds to fully inflate, but a couple hours to repack all 4 floats.

Requires 3 men, talcum powder, a vacuum cleaner, replacing the shear rivet and refilling the helium cylinder.

yt: Emergency Dart Float Test On R66
W: Robinson R66 Helicopter

I just added new github repo, mysql-trigger-logger.

It demonstrates how to use MySQL triggers to log the timestamp, user, SQL and a note for unexpected database changes (“heisenbugs”) from UPDATE or INSERT statements to a table.

This is professional-grade code with documentation and tested notification scripts in Perl, Python and bash, and goes beyond what is available in StackOverflow answers.

github: mysql-trigger-logger

Nice article on what’s new in DNS in the past 2 years – not much apparently, according to Cricket Liu and ThousandEyes.

Also check out the new DNS book from Mark Jeftovic, the founder and CEO of EasyDNS.com.

dnsdist
O2 ‘to seek millions’ in damages over data outage [due to Ericsson SSL Certificate Expiry in 11 countries] HN
Why CISA issued our first Emergency Directive (2019) HN
cambus.net: Fuzzing DNS zone parsers

When deploying a production change, usually you have a rollback procedure – documented even! 🙂

But sometimes after a deploy, things don’t work exactly as expected. At that time, you need to decide which is better: rollback, or fail forward?

If it’s a small, isolated code change and you can operate with the old version, often it’s an easy decision to rollback.

But in more complex situations, sometimes it’s better to accept that the change wasn’t perfect, but:

• is still an improvement overall, and gets you closer to your goal
• or is equivalently bad to the previous situation, but in the right direction
• moves to a new target architecture that can’t be simulated in qa or stage for reasons of time, cost or complexity.
• serves as a commonly-understood stake in the ground, or anchor point. “Now that we’re here, we can see the right direction!”

and keep the change and fail forward instead of doing a rollback.

Generally to know if failing forward is an option, you need:

• enough personal and organizational responsibility to accept the risks and handle the consequences.
• a clear understanding of the overall IT systems and IT risks
• a clear understanding of the overall business systems and business risks
• availability of staff to do verification and fix small issues that arise
• to pick a good time for the change that minimizes stress and risk
• Monitoring and application logging tools help evaluate the situation. (I’d even suggest rounding out your tools inventory beforehand if failing forward is new to you.)
• communicate that you may fail forward if necessary, based on calculated, not reckless, risk assessment and that rollback is still an option.

Some actual examples of when I have failed forward successfully:

• firewall rule changes that were closer to the final goal, but broke a couple of servers temporarily.
• database schema changes that were correct, but required a day or two of minor internal application updates that were not in the original QA test plan.

Some actual examples of when fail forward was not acceptable, and rollback was required:

• changes from httpd 2.0 to 2.4 that actually required significant re-QA and updates to the deploy process
• database schema changes that were correct, but required a major application re-build and re-QA totalling more than 3 hours of downtime
• changes that affected legacy applications with no budget for developers or QA.

Especially with databases, the arrow of time cannot be reversed. So database restores results in the loss of data on busy systems, making fail forward the default policy at many SaaS companies. Additionally, failing forward helps with development velocity.

I recently created a new minimal build system, called pico-build, that is hosted on github.

pico-build is the world’s smallest, yet featureful, three-environment (dev, stage and prod) build and deploy system.

It uses make, but in a different way than normal – pico-build manages entire environments, not individual files.

$ make
usage: make [help|check|dev|stage|prod|dist|all]

It is intended for individual programmers and small teams who want to test and deploy to three environments, but don’t want to spend time setting up (and patching) Jenkins or building a CI/CD pipeline.

Folder structure of a website deployed with pico-build, showing the deploy flow in red

Makefiles, Best Practices HN
Fizzbuzz in make

PSA: If you host domains with Godaddy, and you’re a day or two late in renewing a domain, it will be “parked” – in other words, assigned a different IP address than the previous one.

This is as bad as it sounds, since your site availability and SEO rank will be hurt as various crawlers will cache the random parking pages for varying periods of time, which can last for weeks.

To remove domain parking so that Internet users can see your site again:

1. login to your Godaddy account
2. pay for your domain renewal if still possible
3. find your domain and click on the DNS button
4. look for the parking widget form in the bottom right and click on the trash can to disable parking
5. next to your A record, the status “Parking” should disappear and the pencil icon should re-appear so you can edit it to the correct IP address again
6. do nothing at first for 60 minutes to avoid negative DNS caching. Then try your site, monitor Google search, etc.
7. for future reference, print out your DNS zone settings once it is working.
8. add application monitoring to your site to detect IP and content changes.

Otherwise, contact Godaddy support ASAP.

If you need quick temporary access for intranet/personal use, just add a hosts entry pointing to the domains and sudbdomains you need and restart your browser. Your site will work perfectly, but just for you.

Northrop F5 Freedom Fighter HD
Ron Gibb, former Northrop Grumman F-5 Project Office, conducts a walk-around of the F-5A Freedom Fighter
F-0195 Northrop F-5A Tiger (Ad)
NORTHROP T-38 TALON PROMOTIONAL FILM “THE VERSATILE T-38” 22594
NORTHROP F-20 TIGERSHARK SALES FILM F-16 RIVAL 77364

$15 Million Fighter Jet Has Everything–but A Buyer
W: Area rule, Northrop F-20 Tigershark, Quail decoy/cruise missile
Paul Allen’s F-5B Take-off from SJC (2014)
NORTHROP F-5C FREEDOM FIGHTER VIETNAM WAR
Northrop F-5C Skoshi Tiger MTPF 6.5 hours, Abort rate 1.5%
Garmin Goes Supersonic in F-5

As a commercially-rated airplane pilot who’s read over 2,000 accident reports, I followed the Southwest Flight 1380 fatal uncontained engine explosion closely.

Executive Summary:

The FAA is likely investigating the following concerns:

1. how well did the pilots handle the emergency (it appears well, handling the depressurization event and descending to a breathable altitude.)
2. engine turbine blade failure (engine design and maintenance)
3. uncontained engine shrapnel (engine design)
4. uncontained engine shrapnel into passenger cabin, resulting in the death of a passenger and 7 with minor injuries (plus psychological trauma, esp. to first responders) (fuselage design)
5. improper use of oxygen masks by most passengers (passenger safety briefing, oxygen mask design.)
6. the passenger killed was wearing a seatbelt, yet was partially blown out of the airplane. Was the seat belt worn snugly. If so, do we need 3-point or 5-point harnesses?
7. it’s the first US airline accident in 9 years, and the first en route fatal accident for Southwest. The FAA wants zero accidents for political reasons, and Southwest wants zero accidents as an operating airline.

The oxygen masks descended, but passengers wore the mask over their mouth. Masks are intended to be worn over the nose, so likely the mask shape will be changed and training materials updated.

There are FAA regulatory and political expectations that uncontained engine failures don’t happen. However the physics of large machines with rotating components says otherwise. Likely this will result in armoring the engine shroud and hull with kevlar or metal, and further engine design changes based on energy of rotating components.

There are FAA expectations that the aviation industry mitigates risk so that the uninformed flying public is not injured. However, a passenger died en route.

After the depressurization, oxygen masks were expected to descend and be used by passengers over their nose. Instead they were put over their mouth. Likely passenger briefings will become more detailed, and oxygen masks will be changed from a round to pear-shaped.

Fortunately the pilots descended relatively quickly, at 3,000 fpm, to 10,000′, as:

1. time of useful consciousness at 35,000′ is only about 1 minute
2. the masks were worn incorrectly
3. only about 10 minutes of oxygen is available in cannisters when properly provisioned

However, was the emergency descent actually fast enough? With an improperly-worn mask, generally-speaking the body needs sufficient cabin oxygen pressure within 4 minutes to prevent brain-damage or death.

avweb.com: Southwest Accident Brings Passenger Safety Briefings To The Forefront
philg: Southwest 1380: think about the flight attendants
avweb.com: Southwest 1380: “Flew Like a Rock”
ainonline.com: Southwest Airlines 1380 Engine Failure 4/17/2018 ATC Audio
1 killed as Southwest jet makes emergency landing after apparently blowing an engine in flight

Qantas Oxygen Mishaps (2007 and 2008)

These Qantas incidents illustrate the importance of vigilance when maintaining passenger oxygen canisters:

1) Careless filling with nitrogen instead of oxygen:

theage.com.au: Probe after Qantas pumps wrong gas into jets PPRuNe

2) Oxygen canister valve failure due to unknown cause:

nytimes.com: Officials Ask Qantas to Inspect Oxygen Canisters
telegraph.co.uk: Exploding oxygen bottle caused hole in Qantas jet
smh.com.au: Valve in oxygen cylinder the culprit in 747 explosion

Oxygen canister valve failure causes depressurization in Qantas 747 (2008)

I spent the afternoon at the amazing Hiller Aviation Museum at San Carlos Airport (SQL).

The museum is a real gem, with compact (3 hours to see everything) but nice exhibits in the areas of:

1) Hiller helicopters
2) flying platforms
3) engines from 30 HP (Wright B) to 3,500 HP (Wasp), including a Merlin
4) flight simulators
5) 727 and 747 “steam gauge” cockpits
6) a truly beautiful Grumman Albatross
7) models of most other aircraft

(The Boeing SST that was on loan has been returned to Boeing.)

Flight Simulators at Hiller

Hiller has done a great job of integrating modern computer displays and flight simulators into their exhibits:

Mechanical Flight Simulators

– Curtiss P-2 with map table
– portable flight director
– IFR simulator
– Stearman simulator

Computer Flight Simulators

– 16x PC on 2nd floor (FS9 with Saitek yoke, engine quadrant, and pedals with 3 monitors)
– 1x Redbird FMX full-motion AATD
– Google Earth “wall”
– Wright Flyer (MS FS9 with wood levers and 3 screens)
– a real helicopter with cyclic control and 1 screen

They are moving to X-Plane 11 as PC hardware compatibility leaves FS9 behind.

1) The 747-100 fuselage static display behind the museum lets you climb up the 1st class cabin and sit in the cockpit. It has 5 seats (pilot, copilot, navigator, radio and FAA.) It is closed at 4:30 pm.
2) Behind the 747-100 is a small platform where you can observe takeoffs and landings. It is closed at 4:30 pm.
3) The Burger King next door has a helicopter on static display outside, and historical aviation fotos and a “briefing area.”

avweb.com: Personal Flight Simulators: one-G Simulation

Congrats to SpaceX on the successful launch of Falcon Heavy, with a Tesla for ballast.

And yes, recovering two boosters simultaneously on adjacent pads is showing off, but of the best kind!

One of the main goals of this launch was to not blow up the launch pad, since that would:

1. halve the number of pads available
2. take a year to rebuild
3. and cost about $50 million.

Although it’s always uplifting to see a successful launch, it’s actually valuable to have failures early-on. Having a successful first launch means the rocket was likely over-engineered (ie. heavy.) Hopefully review of the sensor data can find something worth investigating and fixing before launching satellites or people.

One launch doesn’t mean the mechanical and acoustical vibrations between the 27 engines is dampened enough, or even understood at this point.

“In America, if you have lots of money, you can build a space program and launch your own car into heliocentric orbit.” 🙂

SpaceX launches Falcon Heavy, the world’s most powerful rocket
WATCH LIVE: SpaceX to Launch Falcon Heavy Rocket #MarsRocket @3:45pm EST delayed

I watched Superbowl 52 on restaurant cable. Great seat for a great game with the the most ground and air yardage in history.

PHI won 41 – 33 NE in Minneapolis with some nice trick plays in the end-zone.

Brady started the game with an injured hand and had to bench for a while.

Sadly Brandon Cooks didn’t see a legal but huge hit coming after a reception and ran into a player with helmet contact, resulting in a head injury.

The kickers said they “had problems with the in-turf logos.” There were a few missed field goals, including one that hit the post.

Justin Timberlake did the half-time show, but with only 15 minutes to perform his appearance was too brief.

Nick Foles, High-Powered Eagles Stun Tom Brady, Patriots to Win Super Bowl 52

Jack in the Box (Jack and Martha Stewart) and Amazon (Alexa “turks”) had some funny commercials.

time.com: These Are the Best 2018 Super Bowl Commercials

The last 747 has been retired from passenger service in the USA.

I’ll miss the 747 because it was the only widely-used airliner built for trans-oceanic flights:

1. For safety reasons, I’d rather have 4 engines than 2 for trans-oceanic flights. The slow acceptance of twin-engined airliners under ETOPS over the past few decades means greater fuel efficiency for airlines, but in a pinch you’re left with one engine, which is not a good situation for passengers.
2. The 777’s that I’ve flown on to Asia don’t have eyeball air vents, so I end up roasting on long flights.

Delta Retires Last USA 747 to Boneyard

Malaysia hunts owners of Three Boeing 747s abandoned at airport

Macbook Pro 2009/2010 notebooks came pre-installed with Snow Leopard (10.6) Mac OS X.

As of Dec. 2017, very little popular software will work or update on anything older than Mavericks (10.9):

• Several popular chat programs no longer work – Skype app, GotoMeeting, Google Hangouts, Highfive
• No major browsers are supported
• Even Apple updates require 10.8 or higher – for now.

Before you update Mac OS X, note that many users have complained of post-update issues including:

• failure to boot and very slow operation on hard disks. It is possible to downgrade later, but there’s no guarantee that your data will be ok. So backup your files first!
• new, empty keychain folder. Delete it and reboot. (You probably will have to re-enter all of your wifi, browser and application passwords.)
• Xcode will have to be upgraded. Virtualbox will have to be upgraded to open previous VMs, and if you use Dia, read this to fix it
• if your Mac was not purchased in your name, apps like iMovie will not be updatable from the App Store. (iPhoto 2011 will not work at all on High Sierra since it has been deprecated. Your photos will be migrated into the iCloud and accessed with the new Apple Photos app.)
• Restart and Shutdown takes a long time or hangs. If I need to restart with High Sierra, I close the apps manually and hold the power button for 6 seconds to force a power off.
• Resume (open lid to resume) is flaky. Always slow to resume, sometimes restarts.

The best way to update Mac OSX is to use the Apple softwareupdate command line interface (CLI) tool:

1. Confirm you have 2 GB RAM and at least 8 GB free disk space
2. plug your charger in and connect to a reliable WiFi hotspot, or find a tutorial on creating a USB update media
3. Close all open applications, including Textedit.app files
4. Backup your files and all passwords! If the in-place update fails, you may have to wipe OS X and do a fresh install, and the install will likely bork your keychain file.
5. open Terminal.app and run these commands to find out what updates are available, and then apply the updates:
   1. sudo softwareupdate -l (copy and paste the updates list to a file and save it for later reference)
   2. sudo softwareupdate -ia

$ sudo softwareupdate -l
Password:
Software Update Tool

Finding available software
Software Update found the following new or updated software:
   * macOS High Sierra 10.13.2 Supplemental Update- 
	macOS High Sierra 10.13.2 Supplemental Update ( ), 138293K [recommended] [restart]

Otherwise you need to register with the App Store using a credit card to use Software Update. Expect 10 or more reboots/logins and about 4 hours total time if everything goes smoothly. The final reboot will actually install the new software – it will take about 41 minutes on a hard drive, or 20 minutes on an SSD.

Tips

• if you want to keep all your windows open as long as possible, use “Apple … Restart” instead of the installer restart button until the installer says “Ready to Install”
• Command+L on the installer dialog window will show the installer log.

Troubleshooting

• If the install window closes and you want to retry running the installer, open the Applications folder in Finder and click on “Install macOS High Sierra”.
• After the installer is downloaded you will not be able to see the update label name in sudo softwareupdate -l
• An error dialog saying “The recovery server cannot be contacted.” means a network connection error or clock setting error that causes SSL certificate problems
• if the machine becomes not bootable, power cycle while holding Command+R to restore the old OS X and try again while following a recovery tutorial on another machine.

apple.com: High Sierra macOS freezing and stops, HN
W: Macintosh operating systems

Commonly-used country Top Level Domains (TLDs) are often mismanaged.

One of the most popular TLDs is .io, which is owned by The Chagos Islands, known as the British Indian Ocean Territory, hence the .io country domain.

theregister.co.uk: Bloke takes over every .io domain by snapping up crucial name servers
.io name servers down
theregister.co.uk: Telco forgot to renew its web domain, broke deaf folks’ video calls – now gets a $3m paddlin’
hackernoon.com: Stop using .IO Domain Names for Production Traffic HN
theregister.co.uk: Question mark hangs over trendy tech startup domains as UN condemns British empire hangover HN

PSA for Mac OS X users on older machines like Lion and Mountain Lion: if you’re stuck on Skype 6.15, and can’t do video chat after the Microsoft’s July 3, 2017 breaking update …

Apple Facetime is a free video chat application that comes with Mac OS X.

Some tips for using Facetime:

1. It seems to use an entire CPU core, and will quickly drain your battery, so plug in.
2. To add a new contact, you need to know their Apple ID email or their iPhone number. For phone numbers, use the full international prefix with 0 or 1, but without +.
3. By default if Facetime has a window visible (ie. it’s opened), it will enable the camera and consume power. To prevent that, click on the yellow dot to minimize it (ie. background it.)
4. To make Facetime wait for calls, minimize it (click on the yellow dot) or leave Contacts open.
5. If Facetime is not for you, try iMessage/Messages/iChat.
6. Facetime on iPhone is paused automatically when they switch apps and shows a “Paused” message. Facetime is not paused on Mac OS X.

HN Discussion

In the 90’s and 00’s, programmers used to scorn front-end designers who called writing HTML “programming.” That changed when CSS arrived and pixel-perfect results raised the bar.

Here’s some tips for programmers struggling with fixing CSS rendering problems:

Before Getting Started

1. Most programmers are not artists, so don’t write your own site-wide layout CSS. Either find a designer or use bootstrap or an alternative. If you’re doing more than minimal JavaScript programming (ie. using AJAX and/or modeless dialogs), use jquery or an alternative.
2. Treat a CSS project like learning a new programming language. Schedule a day when you’re fresh. You will need all of your concentration ability if you’re new to CSS because of the nested inheritance and browser quirks. If you finish early, that’s a nice bonus.

Getting Started

1. You may want to capture screenshots of what the original site looks like. The Mac OS X Preview app has professional-looking annotation features by Adobe under “Tools … Annotate.”
2. make a backup of the old CSS directory and save in a safe place. Then copy the CSS into a subdirectory so you can use the diff command on the old and new versions
3. if your site uses normalize.css, ensure it’s the most recent version, especially before mobile testing.
4. ensure your network environment has isolation: no load balancers, proxies or far future expires that can cache your old CSS files while testing
5. use the W3C HTML and CSS validators to get a feeling for what’s there and pair each div with /div (I helped debug the original HTML validator.) 🙂
6. use browser developer tools to examine the CSS. My favorite is Firefox’s Inspector.
7. remember the hierarchy with CSS:
   1. the most-specific style wins
   2. the last definition wins, whether at the block or file level
   3. id’s win over classes. (Use CSS classes whenever possible. id’s are more heavily used with JavaScript DOM code.)
   4. pseudo-classes: “Note: a:hover MUST come after a:link and a:visited in the CSS definition in order to be effective! a:active MUST come after a:hover in the CSS definition in order to be effective! Pseudo-class names are not case-sensitive.”
   5. !important wins. (Try to avoid this unless for example you’re fixing a browser z-order rendering problem.)
   6. all bets are off with syntax errors, missing semicolons, or mis-specified class name lists, so fix those first. See below.
8. do some reading online about block and inline element display. Some properties can only be applied to a block element, which usually means adding an enclosing div.
9. CSS uses the original C-style comments of slash-star. Invalid comment characters, like // and #, can cause surprising behavior. Firefox will log “Selector expected. Ruleset ignored due to bad selector.”
   “.

Note: if you’re paying for HTML or CSS, always validate it before payment. Even better, ask your designer to validate it weekly and before delivery.

Debugging Strategies

1. verify if there are any CSS media screen blocks that vary with resolution
2. verify the correctness of individual class definitions, especially lists. if “cascading seems broken”, most likely there is a syntactically-correct but stray ‘div’, ‘p’ or ‘input’ after a class name
3. once the CSS looks sane, you can debug problems by setting enclosing div classes to red or green and refresh your browser
4. if there’s multiple CSS files included, try varying the order
5. to debug rounded corners issues, try setting the background to black or white for maximum contrast
6. test on Firefox, Safari, Chrome and IE11. Budget twice as much time if you want to support IE9 and IE10
7. try overriding a CSS element or enclosing div with an inline style to narrow down a problem.

Emergency Fallbacks

If you’re on a deadline or don’t have story points for a CSS project, there are workarounds.

1. Although it’s better to write classes that apply to all elements, being more specific can fix individual form field problems
2. As a temporary fix, doing an inline style will guarantee what the element looks like.

Getting Done

1. if you’re not working solo, use the diff command to communicate changes to other developers and artists
2. coordinate the checkin. Note that artists often are not version control experts, so you need to find out what the natural flow is or somebody’s changes will get stepped on (seen it twice already.) Investing some time now could prevent big problems later

Little CSS Stuff Newcomers Get Confused About

Related Annoyances

1. maxlength doesn’t work on input type=number
2. it’s more difficult to left-justify and right-justify 2 items in CSS than with tables

Tools

uncss
jhead
CSS Stats
CompressPNG and tools family

TheRegister has an article about a Cisco recall on the ASR 920 Series Aggregation Services Routers PSUs

I enjoy reading TheRegister, but this article is a little light on research.

Looking around online, it turns out that PSUs are often designed for certain altitudes when using air as a dielectric and for cooling, and 2,000 meters is common. However, the current ASR 920 datasheet specifies 4,000 meters, hence the recall.

The real story is:

1. How did Cisco learn of the PSU problem? Device failure, or DC fire?
2. How many other models have the wrong PSU?

Various Configurations of the Cisco ASR 920

When you need to edit a PDF, you really need to edit a PDF.

The free Preview app that comes with Mac OS X can annotate and do some simple operations on PDF files, but does not have a feature to edit the actual text.

I tried the following free or trial PDF editors on Mac OS X 8.5 for editing text on a 30-page Firefox “print to PDF.”

iSkySoft Watermark

Multiple page support for Inkscape

Best Super Bowl that I can remember, with first Super Bowl Overtime.

The New England Patriots (QB Tom Brady) came from behind to win 34-28 over the Atlanta Falcons (QB Matt Ryan).

Atlanta scored 3 TD’s in Q2:

1. Freeman does 3 drives resulting in a flying landing in the endzone
2. xxx runs into endzone
3. did a 82-yard interception.

Patriots got a 41-yard field kick for the 3 points.

Lady Gaga’s half-time performance was good, with surprising acrobatics.

Then the Patriots scored 31 unanswered points to win.

Commercials ($5 million for 30 seconds) weren’t too good, although John Malkovich trying to get his vanity domain from a domain squatter was pretty good (squarespace.com.)

Seemed like mostly cell phone, car and VR-related ads.

W: Super Bowl LI

How to fix “SuccessSuccess” Wi-Fi issue on MacOS X Mavericks temporally

The big news from the SpaceX launch of 10 Aireon Iridium 2G “Next” satellites is that ADS-B was also included on each satellite.

ADS-B is used for tracking and sending ATC digital information to airplanes. The FAA has mandated that almost all aircraft will install ADS-B transceivers before 2020, at a cost of $5,000 to $1 million per airplane, plus downtime.

Since there’s 150,000 registered US aircraft and thousands of foreign airliners, that just isn’t going to happen with the existing number of Mx shops and remaining 1,080 days. 🙂

These are fairly large satellites at 860 kg each:

PSA:

“Changes to eBay Bucks Rewards Program starting January 1, 2017
Effective January 1, 2017 the Base earnings are changing from 2% to 1%.”

Guess I’ll be advising sellers to wait for 8% or 10% eBay Bucks days.

Last time I’ll see one of those.

Basic Economy Fares Don’t Lower Ticket Prices, They Increase Ticket Prices
The Champions of the 401(k) Lament the Revolution They Started

Avweb has an interesting article on ‘Extreme Maneuvering’ about practical applications of the FAA commercial aerobatic maneuvers (chandelles, lazy 8’s, steep spirals) that mentioned “rolling G’s.”

A rolling G occurs when you maneuver an aircraft in more than one axis at a time, causing the airframe or wing to twist. The rolling G design limit is considered to be 2/3 of the normal G limit, according to FAR 23.

Although I performed the commercial maneuvers during my Commercial Airplane practical test and Citabria checkout, I wasn’t really aware of two things:

1. airframe twisting from rolling G’s can more easily exceed a plane’s load limit. Those limits would be lower in older aircraft, possibly already damaged, than newer ones. It’s important to load the airplane one axis at a time.
2. the commercial maneuvers can be used to reverse in a box canyon. I know a private pilot who crashed in a box canyon (he luckily survived) because he knew of no course reversal methods, so this is handy to know.

Chandelle (Climbing, Reversing Turn) Animation

The asymmetric lift, resulting in a torque, caused by the ailerons travelling up and down simultaneously with yawing and pitching maneuvers is believed to have caused several airshow accidents in older airplanes, shearing the wing spar. Contributing factors are the acceleration rate of the control movement, airspeed above maneuvering speed, Va, and wing and fuselage harmonics. Sideslip also affects G limits.

It would be difficult to calculate actual rolling G limits without destroying several aircraft to build a mathematical model. There are a number of reasons for that, but primarily the problem is that dynamic torque must be calculated for multiple types of members, including spars, fuselage skin, and especially attach points. The latter is tricky because attach point hardware may be very strong in one axis, and very weak when loaded off-axis (or corroded.)

pprune.org: Why is Rolling G dangerous?, Normal G limits vs Rolling G limits?
W: Chandelle,
Ice and Tail Stalls

I don’t often go to the movies, but saw ‘Rogue One’ with a date.

The first half seemed kind of slow and disconnected, dealing with various rebel assassination plots (!) on Jedah and Eadu. Good visuals but weak story-telling.

The protagonist, Jyn Eros, portrayed by Felicity Jones, must be a pretty bad actor to have her mother killed in front of her, yet convey being unsympathetic and uninvolved throughout most of the film – I’d rather watch paint dry.

However, the second half dealing with the invasion and destruction of the Imperial base at Scarif and testing of the Death Star was riveting.

Darth Vader’s brutal but ultimately futile light-saber fight scene at the end will please action fans.

And seeing a youthful Princess Leia (CGI) at the end receiving the Deathstar plans was a nice surprise.

The rebels’ companion robot, a re-programmed Imperial model named K-2SO, was intelligent and funny enough to be unsettling. Admiral “Fishlips” Raddus a Mon Calamari, also provided comedic distraction.

Admiral “Fishlips” Raddus. Photo Credit: Lucasfilm

W: Rogue One
IMDB: Rogue One
Can we talk about that final Darth Vader scene in Rogue One?
bbc.com: Rogue One is Star Wars for Better and for Worse
Rogue One: Meet Admiral Raddus, thecharacter inspired by Winston Churchill
Behind the scenes of ‘Rogue One’ with director Gareth Edwards

The story behind Princess Leia’s hairstyle

Keywords: General Fishlips

The sorry tale of the Cessna 162 Light Sport Aircraft (LSA) has finally concluded. The remaining 80 airplanes have been crushed with a backhoe outside the the Chinese factory, including the installed engines and avionics.

It’s believed that liability insurance and parts support didn’t pencil out for the accountants. Crushing solved the liability problem, and also any agreements with suppliers like Continental and Garmin prohibiting resale.

Kind of a shame they couldn’t have sold them to the Chinese government for $1 for use in flight training in exchange for indemnity from lawsuits.

Of the original 1,000 projected orders, 200 were actually delivered and 80 crushed.

There were many problems with the 162:

1. capabilities were Day and Night VFR, not IMC.
2. 1,320 pounds gross weight only left room for one American after full fuel with this design
3. flight schools required a separate check-out, even if you had 152 and 172 experience. This involved additional expense and searching for a slender CFI.
4. price was high for flight schools given the above limitations. The 162 had teething problems, and some owners had to replace the ADHARS twice
5. assembled in China, unlike most trainers.

Cessna Scraps Unsold Skycatchers
Crushing More Than Airplanes
Skycatcher’s Demise: Barely a Ripple [2013]
W: ADHARS

Finally.

TransAsia Shuts Down Amid Safety, Financial Problems

Cirrus SF50 Vision Jet – almost actual size!

It’s a short-range single-engine 4-seat passenger jet for $1.5 million with a parachute that can be operated for $660/hour.

I’ve been following the news on this during the last decade of development. General Aviation (GA) moves slowly, but the SF50 and HondaJet show that eventually small aircraft do get certified.

The numbers:

1. 300 KTAS
2. 2036′ runway
3. 67 knots stall speed
4. FL280
5. FIKI
6. cabin height is only 4.1′.

Obviously it’s intended for existing Cirrus owners who want to step up to a jet.

It uses a Williams FJ33-5A jet engine, similar to the original $800,000 Eclipse 500 jet plans. Williams is a cruise-missile manufacturer, so has lots of manufacturing experience with small jet engines, but not much experience with passenger airplane maintenance.

The Cirrus SF50 is not like this, a Boeing Business Jet (BBJ)

China has bought most of the American GA manufacturing capacity out of bankruptcy in the past decade to position itself for growth in the emerging Chinese civilian market, including Continental Engines (2010), Superior Air Parts (2008), Mooney (2013) and Diamond Canada (2016.)

So far, that has resulted in much-needed investment, though it’s unclear what the long-term implications are for the USA.

avweb.com: Cirrus SF50 Vision Jet: Learning From the Past
aopa.org: Hourly operating costs of 45 jets compared
Mooney’s Fortunes Tied to China
Luxury VIP jets: How the super-rich fly
avweb.com: Checking The China Acquisition Score Card
Cirrus Delivers First Vision Jet

Disbelief at the death of Prince at the relatively young age of 57.

Prince was a musical genius, certainly one of the giants of this century – he wrote, sang, was a virtuoso of 2 dozen instruments, and played guitar at the level of Jimi Hendrix.

He could perform with everybody, or nobody, yet chose to mentor female musicians, introducing them by name in his shows.

I saw one of his shows, but wish I had gone to more.

For business reasons, he never allowed his catalog on YouTube, but there’s a few links from TV performances that indicate his brilliance and show him “bringing the funk”:

Prince & 3RDEYEGIRL Perform ‘She’s Always In My Hair’
Prince Saturday Night Live Full Performance (2014)
Prince playing piano over ‘Summertime’ at Soundcheck, Koshien, Hyogo Prefecture (1990)
PRINCE BET Interview with Tavis Smiley(1998)
“Stand Back” – Stevie Nicks (writer/vocals) with Prince (synths/drum machine), inspired by Little Red Corvette

cnn.com: Prince’s vision for lifting up black youths: Get them to code, Prince’s Death: Latest News
W: Prince
Nicole Scherzinger sings Purple Rain Tribute
Mayte Garcia on the Prince you didn’t know
PRINCE THE MAN BEHIND THE MUSIC ~ FULL DOCUMENTARY

There were a few major earthquakes this weekend:

• Ueki, Japan – 6.2 (foreshock)
• Kumamoto, Japan – 7.0
• Ecuador – 7.8

Hundreds of aftershocks have occurred in Japan.

You would think that Californians, of all people, would be concerned with earthquake safety, but the LA Times has reported on a building safety cover-up involving thousands of older schools and office buildings which will pancake in a major quake.

How Risky Are Older Concrete Buildings?
LA Times FAQ: Concrete buildings, earthquake safety and you
Non-ductile Concrete Buildings

I used to write telemetry collection software for the Space Shuttle, rockets and balloons, but even I watched the SpaceX barge landing with disbelief as the rocket smoothly rotated in all 11 or so degrees of freedom at the same time – no hesitation or staging before the touchdown.

It was like watching a really big lawn dart plant itself. 🙂

twitter: SpaceX
HN: SpaceX Launch Livestream: CRS-8 Dragon Hosted Webcast
theRegister: SpaceX finally lands Falcon rocket on robo-barge in one piece, SpaceX’s Musk: We’ll reuse today’s Falcon 9 rocket within 2 months

A few pieces of MH370, a Boeing 777-200ER, have recently been found on a Mozambique beach, and confirmed as authentic parts.

Their excellent condition and relatively large sizes indicate that the accident wasn’t a high-speed impact with an obstacle or water.

As a commercially-rated airplane pilot, my opinion is that leaves:

1. explosion or decompression
2. descent (or phugoid) into ocean at relatively low speed
3. “graveyard spiral dive” pulled the wings off.

An interesting question would be, “In modern airliners, especially Airbus, anti-phugoid software is deployed. How would that affect an uncontrolled airliner?” Sully said that anti-phugoid software in his Airbus prevented him from slowing descent before impacting the Hudson River.

MH370 Debris Storm
Tourist who found debris was searching for MH370
Turbulence V-Speeds
Australia Confirms Mozambique Debris Came from MH370
MH370: Debris found in March ‘almost certainly’ from missing plane
Investigators Report On MH370 Debris Analysis (2016)
ATSB MH370 Report [pdf]

ATSB Image

Congrats to the Laser Interferometer Gravitational-wave Observatory (LIGO) team for directly detecting gravitational waves for the first time.

LIGO was the NSF’s most expensive project, and took scientists basically from the 1960’s to 2015 to fully realize – initially nobody believed it was possible to actually build this instrument.

Two detector locations with perpendicular 4 km 4-mirror laser interferometers were able to detect gravitation waves from a billion year-old blackhole collision:

Direct Gravitational Wave Measurement of Two Black Holes Merging in 1/10 of a second!

The graph is very interesting and raises the questions:

1. do the pre-impact lobes represent the outer limits (presumably thinner than the center) of the black holes merging?
2. the slope of the lines in the main chirp are very steep … are those spikes much taller (or infinite) than we can resolve?
3. what do the small post-impact lobes mean exactly?

(The local speed of light in a medium is a constant, while gravitation waves distort space, thus changing an interference pattern.)

Basic science is always valuable, but just a few of the reasons why this experiment is important:

1. confirm the equations originally proposed by Einstein in 1915 for gravitation in the GTR and Standard Model
2. confirm experimentally that light and gravitation waves have different propagation characteristics
3. develop the technology to make observations at the sub-proton level
4. study large-scale cosmic events (black holes, colliding galaxies, supernova, binary star systems)
5. study the time of the Big Bang, as gravitational waves are not filtered like EM waves
6. confirm or deny cosmic observations and theories made in the EM spectrum, and provide advance notification of occurring events for study in the EM spectrum.

More generally, measurement tools are the highest form of technology, whether for time, space, EM, or gravity. Any investment of time or money in measurement tools is easily repaid 1000x. For example, the GPS system is the result of accurate time measurement using “atomic clocks.”

This decade is an exciting time for science, as several major terrestrial and space instruments come online or are upgraded.

It will be interesting to see if anybody develops a table-top model of LIGO. Experiments in the 60’s with non-laser methods were susceptible to ambient vibrations, but we’ll see. Cryogenics would likely have to be involved since random atomic motions are larger than the signal being acquired.

LIGO Detects Gravitational Waves for Third Time
Gravitational Waves Detected 100 Years After Einstein’s Prediction
SIGNAL PROCESSING WITH GW150914 OPEN DATA
W: LIGO
Reddit AMA
LIGO black hole echoes hint at general-relativity breakdown
On the time lags of the LIGO signals HN
Gravitational waves from a binary black hole merger observed by LIGO and Virgo
LIGO Architects Win Nobel Prize in Physics
LIGO and Virgo announce the detection of a black hole binary merger from June 8, 2017

Today was the last chance to see Babbage’s Difference Engine at the CHM in Mountain View before the owner makes it private again.

The Computer History Museum has certainly matured into a world-class museum over the years.

The docent talked for about 45 minutes. Unfortunately, it was displayed at the end of a hallway. So 100+ people with kids and strollers jostled to get a view.

It’s very impressive in person – consists of 8,000 parts, weighs five tons, and measures 11 feet long, moderately noisy and mesmerizing to watch. The cranker used a moderately strong rowing motion.

Babbage, in building the first computer, did not have the hindsight to start with a smaller version first. Thus he never finished building a working model despite a decade of funding from the British government and the remaining days of his life working on it.

CHM did a fantastic job on the DEC PDP-1 and IBM 1401 display rooms. Only about 50 PDP-1’s were made, so to have a working model is amazing.