Posts by user "Turkey Brain" [Posts: 5 Total up-votes: 0 Pages: 1]

At this stage, at least two scenarios seem highly plausible:

1. Technical issue

Airliners rely on air/ground logic , which is fundamental to how systems operate.

There have been numerous crashes and serious incidents linked to this logic functioning incorrectly.

Some engineering tests require the air/ground switch to be set in a particular mode. If it's inadvertently left in engineering mode—or if the system misinterprets the mode—this can cause significant problems.

• On the ground , if the aircraft is incorrectly in air mode , some systems may be unavailable—such as wheel brakes, reverse thrust, or ground spoilers.
  
• In the air , if the aircraft is mistakenly in ground mode , flaps might auto-retract, and various layers of system protection may be disabled.
  

In the case of the ANA 787, it appears the engine shutdown occurred during the landing roll, possibly when the TCMA system activated.

2. Pilot misselection of fuel control switches to cutoff

This is still a very real possibility. If it occurred, the pilot responsible may not have done it consciously—his mindset could have been in a different mode.

There’s precedent: an A320 pilot once inadvertently shut down both engines over Paris. Fortunately, the crew managed to restart them. Afterward, the pilot reportedly couldn’t explain his actions.

If something similar happened here, then when the pilots realized the engines had stopped producing thrust, pushing the levers forward would have had no effect. It’s easy to overlook that the fuel switches are in the wrong position—they're far from the normal scan pattern. And with the ground rushing up, the view outside would’ve been far more commanding.

Speaking personally, when I shut down engines at the end of a flight, I consciously force myself to operate each fuel switch independently and with full attention. I avoid building muscle memory that might lead to switching off both engines in a fast, well-practiced habit.

If this is a technical issue, I assume we’ll know soon enough.

I think Boeing assume their pilots will occasionally spill their drinks and designed the cockpit accordingly,
so it will be Boeing pilots balancing their meals on their knees and using adult cups.

Airbus make the mistake of thinking that their pilots are smarter, however it seems Airbus got caught out and their pilots can now only be trusted with sippy cups.

Re; TMCA shutting down the engines. Is it possible that the TMCA was compromised ?

either by

1: fed bad inputs due to corrosion, system degradation, crossed wires, foreign object damage
2: incomplete or inappropriate maintenance action
3: something else

As a pilot with 40+ years of professional flying, currently on the B777, and with some background in modelling aircraft performance, I've got a few observations, having read all posts.


Flaps & Takeoff

The flaps were out for takeoff, which was normal: normal rotation rate, right place on the runway. Debris also shows the flaps were out at impact. The plane's flight path completely matched what you'd expect from a flight with flaps set correctly.


Flight Controls & Pilot Action

To my mind, the controls were clearly working right up to the very end of that tragic flight. This also strongly suggests the plane never had any asymmetric thrust, because there's no sign of yaw, rudder, or big aileron/spoiler movements. The pilots seemed to guide the plane accurately and consistently, just like an experienced crew would. It looks like they were highly skilled from the start: immediately after rotation, they lowered the nose a bit to keep the plane flying. They also bleed off speed to avoid ground contact. Eventually, with no speed left, the plane descends, but it still looked like they were in control. The instinctive pitch-up right before impact is what a lot of pilots would do.


ANC

Why transmit to ATC ? beautifully described by EGPI10BR


Aviate: The aeroplane has decided it doesn\x92t want to do that any more

Navigate: Not many options on where to go

Communicate: May as well let people know it\x92s going to be a bad day and to get there ASAP.


Booster Pumps

Engines don't actually need booster pumps at sea level to get takeoff thrust. (tdracer)


Restart

There's no noise of the engines spooling up at impact. The mobile phone footage just has the RAT noise, normal airframe sounds, and impact noises. I didn't hear any engine spooling up. That witness talking about a "revving, starting noise" sounds to me like he was trying to describe the RAT noise, which we're all pretty familiar with now.


Engine Spool Down

When I did this for real in an actual plane (we had an uncontrollable engine, but also three good ones), stuck at about 30% maximum thrust, at 220 knots, it was an instantaneous spool-down \x96 really dramatic. The yaw came on so suddenly it felt like a heavy catering truck had slammed into us at speed.


Engines

They appear to get the plane to the correct speed and position on the runway as commanded, then at a time very close to rotate they stop providing thrust. The rest of the flight is consistent with gliding flight.


Rotate vs. Air/Ground Switching Vs Pilot action

(This is my take, it might seem counterintuitive, if you know better help) On a normal takeoff at rotation, liquids don't slide backward any more than they do during the takeoff roll itself. They slide back during the takeoff roll, and at rotation, there's actually a slight reduction in those backward forces. The main force is still pushing them back, but because the wings are now generating lift, there's more drag than when the plane was just rolling on its wheels. So, if liquids have pooled at the back of something at rotation, during and just after that maneuver, they'll actually ease forward a bit. The main force is still pushing them back, but it's less so. My take is if something sudden happens around rotation, I think it's probably more connected to something like the air/ground sensing or pilot action, but it is still possible that pooled liquids sloshing forward a little could also cause it.
Pilots have to do a few things at rotate time, pull back in the controls, not the thrust levers in error and then move the landing gear lever. Over the years there's been a few action slips, so unintended control movements.

This energy-based model illustrates Air India 171's flight profile from liftoff to impact. It uses the initial data point from FlightRadar24 of 184 kts G/S, 21 ft height, Google Earth for the crash location, and CCTV footage (originally posted on X) for timing.



A key observation is the calculated average ground speed of 150 knots from the initial point, just after takeoff, to the crash site, derived using the CCTV elapsed time. The model incorporates "best-guess" mid-points inferred from the CCTV footage, which help depict approximate indicated airspeeds consistent with the aircraft's energy state throughout the flight.



The analysis assumes zero thrust during the flight and an average Lift-to-Drag ratio of approximately 12. For this model, a takeoff mass of 210 tonnes and an estimated V2 of 160 knots were used.



Note: This analysis was conducted prior to the release of the AAIB preliminary report, and therefore does not account for the correct take off mass and the actual V2 of 162. The differences are small and as this is a rough best guess, it\x92s just a basic energy model to show the possible trade between speed and height. No account was made of an engine spooling up at the end of the flight. Visual review of the video suggests the thrust from any restarting engine must have been very low, as no significant yaw is discernible.