Air India B787 crash Ahmedabad

[DC3]

All currently speculative of course until the full report comes out.

 

[RSD]

I suspect that they weren’t testing for the lock’s presence, and were using the normal “lift and move” action, without realising that the “lift” wasn’t necessary.

Agreed. How it got through the manufacturing process and quality control is beyond me - the manufacturer would (or should) have had the parts that form the hurdle left over which should have instantly told them that the parts hadn't been installed - long before they were delivered to Boeing and assembled into planes.

The first (and in my opinion) the biggest reason is that it’s a design legacy. We know Boeing designs their coughpits to not over-automate pilot actions. They generally prefer giving pilots direct control, trusting them to manage switches appropriately.

During abnormal procedures (e.g. engine fire or severe damage), you don’t want to have to fumble with thrust lever position as a precondition to shutting off the engine. Time may be critical and if somehow the lever is not fully in the idle stop you won’t be able to shut it down.

For a Boeing design - definitely design legacy, and probably a bit of "if it works then why change it?".

As QF32 showed, when severe damage occurs sometimes the connection between the switch and the fuel valves can become inoperable and you are left with no way of shutting the engine down.

A little bit more information - the fuel control switches that Boeing uses are made by Honeywell. The problem with the switches that had been previously identified wasn't a missing part - it was that the locking system was disengaged - their words not mine - but I interpret that as being that the part wasn't installed in the switch correctly - it may have been installed upside down or something similar.

Some further on these switches.

The original problem that was discovered back in about 2018 was that some switches "were installed with the locking feature disengaged" - which to me seems like odd wording. My best guess is that the faulty switches had been assembled with the locking mechanism installed upside down - but it certainly could and should have been worded much more clearly IMO.

The FAA issued a SAIB with two recommended actions -
- inspect the switches on a wide range of Boeing aircraft to make sure that the locking feature is working correctly
- for Boeing Model 737-700, -700C, -800, and -900ER series airplanes and Boeing Model 737-8 and -9 airplanes it was recommended to check the part numbers and if the switches were of a particular part number then to replace them with a different part that has an improved locking mechanism.

Copy of the SAIB is attached.

 

[markis10]

Probably worth a note that the guards were recommended after a QFlink 717 had an incident on a very similar setup in 2006

 

[Quickstatus]

FAA SAIB NM-18-33

For some reason the above does not always link through:

Can search the FAA dynamic regulatory system and enter SAIB number "NM-18-33", then scroll down the page

..

The gear select lever was not raised, instead the fuel cutoff switches were moved to Cutoff.
Interested to know if "positive climb" was enunciated by the PM, then followed by PF saying "gear up"? prior to Fuel cutoff switch transition. Maybe they didnt get to "positive climb"

Software Glitch affecting 2 separate and unconnected fuel cutoff systems causing the same outcome within 1 second of each switch system?.

 

[jb747]

For a Boeing design - definitely design legacy, and probably a bit of "if it works then why change it?".

Airbus is more or less the same.

As QF32 showed, when severe damage occurs sometimes the connection between the switch and the fuel valves can become inoperable and you are left with no way of shutting the engine down.

Which is why the power off condition is to either run, or no change.

The gear select lever was not raised, instead the fuel cutoff switches were moved to Cutoff. Interested to know if "positive climb" was enunciated by the PM, then followed by PF saying "gear up"? prior to Fuel cutoff switch transition. Maybe they didnt get to "positive climb".

It always looked normal, until around the point where the gear would be selected. Nobody jumped to 'start levers/fuel switches', because it made zero sense.

Software Glitch affecting 2 separate and unconnected fuel cutoff systems causing the same outcome within 1 second of each switch system?.

I expect that there are numerous hidden gotchas within Boeing and Airbus software. You just need the right alignment of the sun and moon.

This is about Space Shuttle software, but it gives an idea...

https://space.stackexchange.com/questions/37110/what-was-the-nature-of-the-known-bugs-in-the-space-shuttle-software

 

[RooFlyer]

A short video of the fuel cut off switches being used I guess you call it in regular operation.

https://twitter.com/x/status/1944609734830539000

 

[AviationNZ]

A short video of the fuel cut off switches being used I guess you call it in regular operation.

https://twitter.com/x/status/1944609734830539000

Not suggesting this was the case, but looking at the timing on that video, it appears possible to manually turn one off and then the other within 1 second of each other.

I feel like there are only a few possible scenarios;

1. Intentional operation, either a massive brain fart or for potentionally nefarious reasons
2. Unintentional operation (i.e. if they didn't have a functioning lock mechanism) such as knocking them both down by mistake
3. Faulty electrical operation on both switches happening at the same time but isn't a permanent issue as they were able to adjust and re-light

#3 feels like a massive stretch, not impossible but highly unlikely.

 

[NM]

Not suggesting this was the case, but looking at the timing on that video, it appears possible to manually turn one off and then the other within 1 second of each other.

I feel like there are only a few possible scenarios;

1. Intentional operation, either a massive brain fart or for potentionally nefarious reasons
2. Unintentional operation (i.e. if they didn't have a functioning lock mechanism) such as knocking them both down by mistake
3. Faulty electrical operation on both switches happening at the same time but isn't a permanent issue as they were able to adjust and re-light

#3 feels like a massive stretch, not impossible but highly unlikely.

Option 2 very unlikely that BOTH switches would both toggle 1 second apart unintentionally and without noticing.

Option 3 seems inconsistent with one of the pilots asking the other why they "cut-off" if the switches were not actually moved, unless it was reported as such on a display??

At this stage it would appear to be Option 1, but unable to determine 1a vs 1b. But Options 2 and 3 do remain although seemingly very low probability compared with Option 1a or 1b.

 

[mjt57]

In that report it says that the Captain had an ATPL and the FO a CPL. Is that normal for FOs to not have an ATPL?

 

[AviatorInsight]

In that report it says that the Captain had an ATPL and the FO a CPL. Is that normal for FOs to not have an ATPL?

Yes. Having an ATPL will allow you to be the pilot in command. Usually as a minimum, airlines will require CPL holders to have their ATPL theory completed so all they are doing is waiting for their hours to tick over to then gain the ATPL licence itself.

But technically all that is required, is a CPL at a bare minimum. That just allows you to be paid in the industry and act as the first officer of transport category aircraft.

 

[RSD]

Hopefully this link works -

172K views · 50 reactions | This is the locking feature. This feature is to prevent accidental movement of the switches. To move the switch, you need to lift the switch over the locking feature. As you can see in the video, it is impossible to move t

This is the locking feature. This feature is to prevent accidental movement of the switches. To move the switch, you need to lift the switch over the locking feature. As you can see in the video, it...

www.facebook.com

 

[mjt57]

But technically all that is required, is a CPL at a bare minimum.

Ah, good, that explains it. How many hours are required? This FO seemed to have quite a few up.

 

[AviatorInsight]

Ah, good, that explains it. How many hours are required? This FO seemed to have quite a few up.

According to the DGCA (India’s version of CASA) it’s 200hrs. That is also required to apply for a job as a trainee cadet pilot at Air India as well.

 

[jb747]

In that report it says that the Captain had an ATPL and the FO a CPL. Is that normal for FOs to not have an ATPL?

If the airline uses multiple FOs or SOs instead of multiple Captains for long haul ops, then the FO being left in charge will require an ATPL.

 

[Happy Trails]

But when the FA's are left in charge...

Pilots suspended for handing over control to air-hostesses for a 40-minute loo break

One of the two air-hostesses switched the auto-pilot off while fiddling with buttons; both members of cabin crew too suspended

mumbaimirror.indiatimes.com