"These pilots ignored just about every warning under the sun being thrown at them, ignored ATC instructions to go round to loose height and speed, even tried apparently to slow down using engine thrust when bouncing down the runway then still took off again, nobody on the airport thought to tell the pilots their aircraft had touched down on their engines"
I'm curious, although with hindsight we know what happened in this case. Would they have had an option to drag along the runway and complete the landing if they'd been advised that they had used their engine cowlings as landing gear? Clearly taking off again and going for another landing didn't work out for them, and I'm speculating, but what options would they have had if the message that they'd touched down on their engines had been received? I am also assuming that as per Mr. Heaton's notes, that the ability to go around in this case is engine dependent as well as extent of damage dependent.
The main option was a hard turnaround directly to the opposite direction on the runway instead of a large go around. This has been done on other occasions of engine failure after takeoff.
But to know that they needed to do that they would need to know that critical parts of the engines had been damaged in spite of the fact the engines were continuing to operate while they made that decision. Given they lacked the wherewithal to avoid the entire problem by simply going around and entering the approach at the correct speed and altitude, the likelihood they would know the details of engine lubrication are zero.
I thought they were halfway down the runway, nearly 100 knots faster than they should have been, with no material under the plane with a high coefficient of friction and no way to trigger the lift-killing spoilers because no weight on wheels; this would mean that ground effect would prevent much friction force being generated. Odds are they would continue at over 100 knots off the runway end into whatever surrounds the airport, about the same speed they crashed with.
To be honest I am surprised they could even select rev thrust. We have a lockout that we can't select it until all three WOW sensor circuits are positive weight on wheels. In the old days some of the three holers you could select the middle tail one in the air. There is a huge click when it gets released.
I agree with 3D that once they touched down they were going off the end of the runway what ever happened.
I was always taught better to crash somewhere where there is a fire service ready and trained to deal with aircraft than off airport.
I think Karachi has retard pits off the end of the runway. Looking at google maps seems to look as if they have
The whole place got upgraded in 2010 ish for the A380 starting ops and everything will be designed to stop one of those slugs in hot weather.
These pits sink the aircraft into a high friction medium in this case it would be sand which at those speeds would have broken the aircrafts back but possibly more would survived.
Personally I would say its better to stay on the ground. If you have just touched with the belly what ever engines you have onboard. It's apparently the FADEC that gets scraped off. After that you have 90 seconds before the fuel valve closes. There are various backup and swap over systems normally ie each one has 2 channels and if one channel goes you end up with two primary and the third is used as a comparator. Both go same engine the other side takes over. When the third one goes you still keep both engines and its channel does both. But you still keep flying. When both FADEC's get taken out that's when you get this dual flame out. BTW this isn't a feature of any aircraft make. This is purely an engine manufacturer thing, they have to deal with the certification of the engines.
Turbine engines are usually pretty hardy with lack of oil to be honest. You might kill them for later use but no oil for a while won't kill it instantly and it will be more issues with increased temperature and a gradual loss of thrust. They certainly won't seize 90 seconds after oil pressure is lost. in fact it was a sim session I did, one got shut down due low oil pressure and then the other one went on fire 20 miles out from the airport. I just started the low oil pressure one again and then put the fire out on the other one shutting it down. Lost control over the propeller RPM it went full fine pitch which meant the over speed fuel controller took over at high power settings. But apart from that it was pretty uneventful the engine temp hardly increased at all.
This dual fadec 4 channels complete failure is a numbers game. 4 channels is above the 3 layers of redundancy and level A design requirements. Its happened once before in Tallinn with no fatalities, this is the second time. I really don't have a clue if it will trigger the regulators to push for a design change requirement. Which may only be that the automatic closing of the fuel valve is removed on complete fadec failure on both engines.
To add the name is Alistair which is what I introduce myself as in all situations. If local accents find it difficult to say then its Ali, I also respond to baldy and fatty and daddy. Which is something that never gets mentioned in these accidents the number of kids that have to live with the results of missing parents.
