Frontline 2
Boeing’s Fatal Flaw
I’m not sure if there are any new details They said early on in the program that Boeing immediately suspected MCAS after the first crash and alerted pilots. That was a one line statement without explanation. I would expect that communication to be with airlines and not pilots.
The chief pilots who tested it’s first flights said the plane needed low speed help so the MCAS was brought into play. It was originally designed for high speed interaction to avoid stalls and now it was active down to Mach .2 for low speed handling. I’m guessing this allowed MCAS to react to a high speed event at a lower speed.
A Boeing test pilot had extreme difficulty in a simulator that in his opinion would have brought the plane down.
They again reiterated Boeing’s position that pilots would recognize a runaway trim situation. The FO of the 2nd crash called out a runaway trim and I believe he was the one who turned it off. The PIC eventually turned it back on. They didn’t explain why that was done which could already be because there was too much force on the stabilizer to manually re-trim. They mentioned the MCAS was more aggressive than regular trim to the tune of 4X which is pretty significant. The video of the trim wheel showed it moving pretty quickly but they didn’t specify that was a video of MCAS in action. They also didn’t mention if a crew would ever experience MCAS in action. It was to avoid a stall on climb out but no mention was made if such a condition was regularly experienced. Max pilots can expand on this regarding any new training that’s been incorporated.
Another contributing factor was an improperly adjusted AOA sensor which I assume followed a write-up from a previous crew who experienced the same issue. They didn’t mention a previous event.
They then went on to the door plug issue.
Here is a link. Frontline says this is an update to their 2021 documentary and includes what as happened to Boeing jets as recently as January, 2024. Is there much new here? I have not watched it all yet. @Magiver seems to think there is not a lot new here.
53 minutes:
Is there any reliable information yet on the Boeing LATAM 787 that encountered trouble approaching Australia? Most snippets of news I’ve seen refer to a sudden and unexpected drop but last night there was a fragment of a story about some device that had to be rebooted every 22 days or it just would shut itself off! While that doesn’t make sense to me as a layman - is it true or was it just more uninformed wild ass speculation?
There does not seem to be much new here. Just some more recent stuff tacked to the end.
I like Frontline a lot but this seems a bit low effort. That said, I can’t imagine them making a whole new documentary just because a few added things happened so, I guess it makes sense to just tack those bits on.
Here’s another Cirrus saved by its 'chute. Whitehorn, CA.
Nothing much at the moment. There have been several AD’s (Airworthiness Directives) regarding depowering the aircraft but it’s not clear if they’re related.
The 51 day issue is linked here EASA Safety Publications Tool. That doesn’t look related to the incident at all to me, as it discusses invalid data being presented as valid.
Potential consequences include:
- Display of misleading primary attitude data for both pilots.
- Display of misleading altitude on both pilots’ primary flight displays (PFDs).
- Display of misleading airspeed data on both pilots’ PFDs, without annunciation of failure, coupled with the loss of stall warning, or over-speed warning.
- Display of misleading engine operating indications on both engines.
The LATAM incident was reportedly caused by a complete loss of power which sounds more like an older AD requiring a power reset every 248 days https://ad.easa.europa.eu/ad/US-2015-09-07. This AD has been superseded by a newer one requiring a software update to the generator control units.
This AD was prompted by the determination that a Model 787 airplane that has been powered continuously for 248 days can lose all alternating current (AC) electrical power due to the generator control units (GCUs) simultaneously going into failsafe mode. This condition is caused by a software counter internal to the GCUs that will overflow after 248 days of continuous power. We are issuing this AD to prevent loss of all AC electrical power, which could result in loss of control of the airplane.
The new AD is here EASA Safety Publications Tool.
To break it all down. The AD requiring a power reset prior to 51 days (I think the actual maintenance interval was 25 days but that information is not included in the AD) addresses a failure that does not seem to be related to the LATAM incident. The AD requiring a power reset prior to 248 days has since been replaced by one requiring a software update. Given it was issued in 2018 and the update was provided free of charge by Boeing, it seems likely that LATAM had already complied. It also seems unlikely that a B787 would remain powered for that long anyway, but it’s possible.
The 787 sounds like the old Microsoft blue screen of death.
Based on the crash of Air France flight 447 I would make a wag that the pilot had to trim the plane under high altitude manual procedures. Something has to be done very quickly to ensure control of the plane.
I didn’t realize that the show was just an update of a previous episode. No much new. What I still find unfathomable is that there existed a system where the failure of a single component (in this case an angle of attack sensor) could doom the plane. I’m just a glider guy but anyone with a basic understanding of flight, knows how important (one could say “critical”) angle of attack is to safe flight. When asked about this single point of failure problem and how it could happen, the CEO punted and said something along the lines of “We’re looking into it”.
One of the engineers interviewed said that he pointed this out to higher ups and was ignored. Are there any other such components? I thought that every critical system had at least one back-up.
Lastly, at what airspeed does the manual trim wheel become impossible to turn?
The unmodified MAX was completely flyable with runaway MCAS. A Lion Air crew flew the previous flight of the accident aircraft for 90 minutes over the ocean at night with a full bore failure and laconically wrote up the malfunction. Whose repair was pencil-whipped.
I’ve flown the Lion Air crash scenario in the sim. Distracting, but not challenging.
The real problem was Boeing airplanes from the 1960s can’t safely be operated by people whose pilot training is more suited to operating an automated subway train.
Is new MCAS v2 more robust against failures? You bet. Was an AOA hardover with MCAS v1 a guaranteed crash ? Not even remotely.
They said MCAS was 4 times faster. That makes it sound like it moves the trim at 4 times the speed as a pilot’s trim switch. If that’s the case wouldn’t it be scary obvious to see the trim wheel spinning like a circular saw?
That’s false. The MCAS v1 (and v2) trims at the same speed as the pilot’s switches. Which is still pretty fast, and jumpseat riders unaccustomed to watching that thing spin are often amazed / concerned with its normal operation.
What is true is that the autopilot trims at 1/4th the speed of MCAS & the pilot’s switches. So compared to the typical thing you observe where the autopilot is on and the trim runs on its own for a couple seconds every couple of minutes, MCAS is 4x faster. MCAS of course only operates while the autopilot is off.
What did change with v2 is now it runs in short bursts with short pauses between bursts. Partly so the average trim rate is less, but also as a recognition signal that this is MCAS talking, not something else.
Although if MCAS (v1 or v2) was to run away due to AOA failures / hardovers, you’d also have a stick shaker as corroboration that something was amiss besides just routine trimming occurring.
There is. The design philosophy of the 1960s is the left and right halves of the airplane are completely independent of each other. And each one is equipped with its own pilot. The pilots are the mechanism that compares the two sides, decides what, if any, malfunctions may be occurring, and then operates using the good system(s) while ignoring the bad.
This system fails utterly when you put inadequately trained barely-pilots in the seats. Which is the norm in much of the poorer and rapidly growing world where much of Boeing’s sales are occurring.
Most of the flail about Boeing certification is how exactly they and the US FAA square the circle that a 1960s legacy design can’t be flown safely by modern (mostly non-US) not-quite-real-pilots. While neither side can stand to say in plain words that that’s what’s going on.
Some of the flail is Boeing’s craptacular and evidently corrupt management practices. But from an engineering POV, my prior paragraph is the nub.
How much do these airplanes cost? I thought they were hugely expensive. And if they can afford to buy these why can’t they afford to pay for pilot training?
Did the pilot wedge his SLR camera between the seat and the sidestick, like this one? (Links to a MentourPilot video from a year ago)
It’s an attitude. Third world entrepreneurs generally believe all labor should cost $1/day. And there’s no such thing as skill that matters. They can hire people who tell that’s so so they’re happy. This shit at the bottom of the pyramid is another matter.
B787 has a conventional yoke so its unlikely to be a foreign object, more likely they were slouched back with their legs in front of the column or something like that.
They must have been right at the CG limit.
I don’t see that CG has anything to do with it. The likely scenario is the pilot had a leg or some other obstacle in a nonstandard position and moved the seat in a way that pushed the obstacle unnoticed into the yoke. Boom: instant dive and instant massive confusion from both pilots.
When you sit tied to a chair for hours on end, it’s not uncommon to scootch (technical term) your butt around, cross or uncross legs, sit semi-sideways awhile, etc. Strictly speaking it is prohibited to unbuckle and stand up to stretch. Although it gets done.
I thought it was a joke: That they were so near the CG limit that the pilot moving his seat pushed it over.