Posts about: "Preliminary Report" [Posts: 277 Pages: 14]

Originally Posted by Mrshed

Don't think it neccessarily adds anything for me, other than:

- Would we expect ADS-B data to stop on engine transition to run? Note that ADS-B data was received between 08:08:43 and 08:08:51, so apparently only received in the time window that the switches were in "cutoff"
- The window between the switches being shut off and moved to run could be as short as 8 seconds, and the window between engine 1 and engine 2 being moved to run could be as short as 2 seconds
- The statement on the CVR could be a wide range of timepoints.

The ADS-B data is in my view odd, albeit this might be my lack of understanding. Yes, not synchronised, but unless the timestamps are way out (like 10 seconds out, and given the timestamp of max altitude, this feels incredibly unlikely), ADS-B data was transmitted without issue during phase 2 (both engines off, no RAT), and phase 3 (both engines off, RAT)...but NOT phase 4 (both engines firing back up, presumably still with RAT?). Bear in mind that phase 4 is almost half of the short flight. Also it would appear no data during phase 1 (both engines on), including during takeoff, despite receiving data during taxi?

Originally Posted by CharlieMike

I\x92d counter that order of likelihood by suggesting

(1) It\x92s still a likely response to ask that question if your colleague had just switched them off by action-slip.
(2) See my post above. Routine use of these switches is in one \x93event\x94\x85below OAT 40C you start both simultaneously and at shutdown you operate one straight after another.
(3) The interim report seems to leave out all information on verbal exchanges not specifically involved with a response to the abnormal situation.

Not saying you aren\x92t correct, but it doesn\x92t change the order of likelihood in my mind.

Originally Posted by RexBanner

It actually doesn\x92t matter who said it for the purposes of diagnosing deliberate action, if it\x92s someone trying to cover their tracks and deflect blame onto the other person it still represents cognition that the movement of the switches was a deliberate act and will have been recorded as such.

Originally Posted by adfad

(1) is true I give you that, but there is no followup "I didn't.. oh crap", denial is a reasonable response if you truly haven't registered doing something, but it is also a reasonable response if you want to confuse to delay

By precedent in routine operations I mean: is there a single example of these switches being cut off at takeoff like this? There is precedent for the wrong engine being shut down in a fire sure, and there is perhaps precedent for mishaps with the fuel switches in other cockpit layouts - but in the case of this layout, with this model of switch or even this 'style' of switch and placement, I cannot find a single example that would come close to the level of catastrophic action slip of pulling out and setting to cutoff both switches one by one.

I think the preliminary report is supposed to present all factual information - they could have left out "why did you cutoff / I did not" - I could understand if they left out sounds that could be ambiguous, perhaps indicating a struggle but not clear enough to present as fact. However, "positive rate / gear up" followed by 2 switches instead of gear handle is completely factual and relevant information, to exclude it makes no sense.

Originally Posted by Hawkeye777

THE LANDING GEAR

There are many missing jigsaw pieces here that are highly relevant to building an understanding of what these guys were going through.
One being that the gear was not raised. The report ( very oddly in my opinion ) is NOT declaring any voice data on the prompts/commands to raise it once they achieved a positive ROC after lift-off.
At lift off, it's pretty safe to assume ( yes, I know ) that everything was going according to plan....so why, oh why wasn't the gear raised.....?

This is quite extraordinary because:-

1. This sequence is muscle memory for every commercial pilot. It\x92s drilled into simulator sessions, route checks, and emergency training. Even during non-normal scenarios like an engine failure, the gear is typically raised before handling other procedures.
   
2. The delay is not explained in the preliminary report. The gear lever was found in the DOWN position in the wreckage. No mention is made of any mechanical failure or crew discussion about the gear. That silence is notable.
   
3. There was no declared emergency prior to 180 kt. No CVR audio so far suggests anything unusual before the sudden power loss\x97so there was no obvious reason to skip this SOP.
   
   
   

Originally Posted by Mrshed

Not sure if this is helpful for anyone or not but I thought a visual view of the timeline of events might be useful, in seconds since V1.

Originally Posted by Capn Bloggs

@Maybeitis, how about we leave the total redesign of the fuel switch locations and operation (which have been moved billions of times in thousands of aircraft without a hitch) until the final report is out.
These were deliberately moved. It wasn't a brain-fart. Unless the interim report omits crew calls which turn the scenario on it's head.

Originally Posted by B2N2

You don\x92t \x93flick switches in the Sim\x94 for no apparent reason.
Even Indian sources are now reporting on the possibility of intent.

https://www.ndtv.com/india-news/air-...-probe-8864239

Originally Posted by SRMman

I still think that one of the most puzzling things from the Preliminary Report is the 4 second gap between Engine 1 fuel cutoff switch being returned to RUN, and that of Engine 2. It seems generally agreed one second is a reasonable time to operate both switches, so why did it take so long to move the 2nd switch?

Originally Posted by SRMman

I still think that one of the most puzzling things from the Preliminary Report is the 4 second gap between Engine 1 fuel cutoff switch being returned to RUN, and that of Engine 2. It seems generally agreed one second is a reasonable time to operate both switches, so why did it take so long to move the 2nd switch?

Originally Posted by SRMman

I still think that one of the most puzzling things from the Preliminary Report is the 4 second gap between Engine 1 fuel cutoff switch being returned to RUN, and that of Engine 2. It seems generally agreed one second is a reasonable time to operate both switches, so why did it take so long to move the 2nd switch?

Originally Posted by SRMman

I still think that one of the most puzzling things from the Preliminary Report is the 4 second gap between Engine 1 fuel cutoff switch being returned to RUN, and that of Engine 2. It seems generally agreed one second is a reasonable time to operate both switches, so why did it take so long to move the 2nd switch?

Originally Posted by Captain Biggles 101

With the greatest respect, I don't think any deliberate act has been proven. Allocating blame on assumptions should be avoided. People should work on facts, and then unconfirmed assumptions.

The only known fact is that engines for some reason were shut down. The other known fact is that there is a recorded indication that the start lever command was recorded as both cutoff in short succession then followed by idle detent causing a restart attempt.

I think the key unknowns here are important.
1. Was the start lever position recorded, or only the electrical signal? My money is on an electrical signal not position, therefore the manual positioning of the start levers is not conclusively proven.

2. The bulletin for locking mechanism for the start levers has been mentioned in the preliminary report. This is a huge unknown. Did that mean that in a failure that the levers could both move into cutoff at the same time? This occurred exactly as the aircraft was rotating and increasing pitch.

3. The information from the CVR if taken at face value must not be discounted. No pilot actually confirmed conclusively seeing the other move the switch. This could have been an assumption noticing an engine failure, seeing the start levers positions in cutoff or indeed seeing the start levers moved deliberately. This is a huge critical unknown.

4. One pilot asked 'why did you cutoff' and the other responded 'I didn't'. This is not a confirmation of anything for sure. In fact it is equally a suggestion nobody pilot moved the switches as it is saying they did. This is not conclusive. This raises an important question, was this genuine, did either pilot have any reason in their life to attempt to do this and then cover their actions? There is zero suggestion here either way, but hopefully investigators will already be looking at their backgrounds and state of affairs.

5. There is no indication who or what commanded the engines back to idle detent again. There is proof of both engines attempting to restart. I would take this as confirmation of teamwork existing on the flight deck, and this would suggest a lack of deliberate interference by either pilot. Should that have been deliberately done, so much more could have happened. It just hasn't been alluded to in the preliminary report.

My own impression is that it did not appear to be a situation of a deliberate act to crash. I say this as they appear to have both tried to save the aircraft and immediately restart the engines and recover taking some critical timely actions demonstrating competent reaction.

The timing of the commanding fuel to cutoff os critical imo. The aircraft was pitching. If an accidental command to cutoff occurred then I feel this however unlikely would have been made instead of another action. The only likely thing happening at that exact time or due 2-3 seconds after lift off was gear up. The CVR and recorded timing of engine failure in relation to that challenge and response in SOP will be key imo. Did the challenge for gear up occur before the idle detent electrical signals? Also, the focus should be on that bulletin for the locking mechanism for the start levers.

I just cannot imagine an experienced crew doing this by accident and the information just doesn't suggest a deliberate act.

My post is just to highlight huge lists of unknowns. The media appears to have made their mind up that the flight crew did this. I just highlight that is definitely not confirmed yet. We have a whole list of unknowns and conflicting communication that raises more questions than they solve.

I would urge zero conclusions be made, and RIP the crew and passengers. There are zero conclusions to what happened yet in my opinion, and I think the suggestion to relatives of the flight crew and families tragically killed that this is a known pilot deliberate action simply cannot be made at this point. We must not blame the flight crew prematurely or pretend we know what happened. I think the media should take note and back off from all the assumptions.

Originally Posted by rigoschris

It\x92s not great that they mention the SAIB in the Preliminary Report but don\x92t give any details to the state of the particular switches of this airplane.

The metal parts of the switches seem intact in the picture, so it would be easy to check if the \x93lobes\x94 in the movable and stationary parts of the switches were there. A close-up picture would lay this topic to rest.

This omission is causing a lot of speculation online.

Originally Posted by ACW342

Back in the days before it became illegal I used to blag my way into the cockpit on short haul flights using my RAF ID card. Part of the cockpit checks, if the third seat was occupied, was the question "Pax, seat belt on and secure?" to which I always responded "Seat Belt on and secure". I am sure that that Question and Response is still used on check lists and if that is the case that Q&R would have been recorded on the CVR. That should, hopefully, do away with the 'third person in the cockpit\x94 theory ACW342

Originally Posted by FullWings

I think what more likely did away with that theory for the investigators was the absence of the remains of a third body up the front and any audio of the door opening after the switches had been pulled?

As far as the gear lever being in the down position in the wreckage, it could be that the engine shutdowns occurred before the positive rate call and/or the gear was selected up but put down again when a forced landing became inevitable. The only paraphrased communication we have is to do with the engine controls - there was probably more but the preliminary report has omitted it because it\x92s not really relevant to the main event?

Originally Posted by Musician

The event shows that it's really imperative to relight the engines as quickly as possible.
The preliminary report says it took about 5 seconds for the engines to spool down to idle. 14 CFR \xa7 33.73 - Power or thrust response requires a jet engine to reach 95% thrust from stabilized flight idle in not over 5 seconds. So with a sufficiently quick reaction, flipping the switches back after 5 seconds, they could've been back in business by the time they actually flipped the switches back.

So it's not "flip the switches 3 seconds after liftoff and you're unrecoverable"; to be unrecoverable, there must also be sufficient time for the engines to spool down enough.

Don't ask, "why did you cut the engines", flip them back on. Go for the E in PACE.