Lion Air Crash

[Colin Leighfield]

All spot on Jon, but there’s still the later disclosure about the wheel spacer being left out causing wheel drag that caused the plane to be at the edge of the runway and below normal take-off speed. If there is a root cause that’s it. From then on the chain of events was inevitable once it was initiated. If it had been centre-line none of it would have happened. Whether or not the debris would have caused any other accidents before it was cleared is anyone’s guess?

[Jon H]

Posted by Colin Leighfield on 20/11/2018 12:17:42:

All spot on Jon, but there’s still the later disclosure about the wheel spacer being left out causing wheel drag that caused the plane to be at the edge of the runway and below normal take-off speed. If there is a root cause that’s it. From then on the chain of events was inevitable once it was initiated. If it had been centre-line none of it would have happened. Whether or not the debris would have caused any other accidents before it was cleared is anyone’s guess?

The lecture i went to stated that the aircraft only drifted to the edge after the tyre went. The wheel spacer didnt help during that phase but was considered non critical in terms of the outcome. I have heard the other version of the story, but this photo seems to show they were on centreline until after the fire broke out.

https://www.1001crash.com/latest/2000/concorde/piste.jpg

 

The suggestion made during the lecture was that they hauled it off the ground early as they couldnt seem to control the yaw and were trying to avoid a 747 down the end of the runway.

In either case, you only need one link to break the chain of events. 

 

Interesting though the conversation is, we are probably a little off the op topic....is anyone worried about that? 

 

 

Edited By Jon - Laser Engines on 20/11/2018 12:57:50

[Colin Leighfield]

Thanks Jon, I hadn’t seen that before and it alters the perspective. You are right about being off-topic now, I apologise for contributing to that.

[Jon H]

Its my fault, i brought up concorde. I dont see it as a problem. It was a natural progression of the conversation, i just dont want to anger the mods

Also, my photo disappeared! where did it go?

I have tried to link the photo again but computer says no. 

Just go here https://www.1001crash.com/latest/2000/concorde/piste.jpg

Edited By Jon - Laser Engines on 20/11/2018 12:57:37

[Piers Bowlan]

Lion Air:- 'Increasing speed and decreasing pitch'. Gordon, they had taken off in day VFR so despite the duff information coming from the instrumentation plus the unreliable IAS and Altitude messages, they would have been in no doubt that they were descending towards the sea. They could see it. The handling pilot would have been pulling with all his might to prevent the aircraft from pitching down, once the stab trim system had run away to a full down. Perhaps both pilots were pulling on the control column in an effort to overcome the out of trim condition? Sadly to no avail, as the aircraft was decending at 7600 fpm when it hit the water.

Regarding the Concorde disaster my recollection of reading the accident report was, from the CVR (cockpit voice recorder), the flight engineer shut down the no1 engine which was on fire but he then shut down the no2 without waiting for the Captain to confirm. Although the no2 engine had a fire warning too it was still producing useful thrust and more importantly producing hydraulic power. Once the flight engineer shut down the no2 engine their fate was sealed as they no longer had the hydraulics to raise the gear, preventing the aircraft from accelerating. From that point on they were trading speed for altitude until the aircraft finally stalled.

The vulnerability of Concorde to FOD was well known which was why BA had their Concorde fleet fitted with 'cow. catchers' to deflect debris from being thrown up unto the engine intakes on take off. They also had a runway inspected before every Concorde take off. Their aircraft were also fitted with alarms to warn of a burst tyre. Air France and their regulatory authority did not think any of this necessary. The most serious revelation to come out of the Air France Concorde crash was that with a full load of passengers plus enough fuel to fly to Miami non-stop the aircraft was above it certified max take-off weight.

Bit off topic again!

[Jon H]

I thought it was other way round Piers, i thought he shut down no2 first (and without a nod from the capt) and then no1 failed once the wing essentially burnt through. Apparently the gear didnt retract because the interlock switches on the inner gear doors were damaged so the system thought the inner doors were still closed and it didnt let the gear retract.

Either way, you are right it was a contributory factor, but to be honest once it caught fire it was pretty much doomed anyway

With the 737, its a bit of paradox really. You want a trim/stick push system that is strong enough to override pilot input in the event that the pilot has become disorientated and stalled. In this case he may well be pulling with all his might due to confusion, its happened many times before so the system needs to have enough power to cancel that out. However, in this case having the pilot able to override the system would clearly have been advantageous.

[Piers Bowlan]

I think you are right Jon, your memory certainly seems better than mine.

The pilot could override the system if he followed the 'Runaway Stabiliser checklist' which is a memory item, but he has to correctly diagnose what is happening to do that. Easier said than done in the dire circumstances they found themselves in. However, Boeing never bothered with a 'stick push' system before so perhaps they should leave 'protecting the pilots from themselves' to Airbus in future!

Edited By Piers Bowlan on 20/11/2018 15:17:19

[Jon H]

Its safe to say that if you are on a standard climb out in good conditions and find that in an instant your aircraft wants to return to earth as violently as is being suggested here its not a surprise to me that thing like checklists and memory items go completely out of the window. The shock must be something unimaginable.

I dont know if anyone listened to the audio of that E190 in portugal that had a flight control system and instrument failure (while in full IFR). The pilots were so focused on the task at hand they were unable to process new information. They kept asking for a heading to the sea for a ditching but were unable to recall the instructions given and 'common sense' information like the sea always being to the west was lost. Im not faulting them, its just part of the human factors bit. We dont like to be surpised!

In any event they managed to wrestle the aircraft down safely which was an excellent job all round.

[Gordon Tarling]

Piers - the cow catchers to which you refer were water deflectors, nothing more, nothing less. BA did NOT have the runway inspected before every takeoff. Neither was there any tyre pressure indication or warning system fitted - tyre pressures were checked the hard way.

[Piers Bowlan]

Thanks for the correction Gordon, Yes the cow catchers were water deflectors which BA modified (strengthened) after they had a serious incident where one broke away rupturing a fuel tank on take off. Air France didn't think the modification necessary. There was speculation during the investigation that it was a broken cow catcher that was responsible for the Air France crash.

I believe the runway inspection thing has become something of a modern myth apparently and probably started when Concorde departed New York on the first departure of the day; the runway was swept (inspected) before it took off but would in fact have been swept for any first departure of the day.

I read that Concorde had a tyre deflation warning system fitted that was active between 10 and 135kts on take off. I didn't find that information in any technical manual however so it is probably more 'fake news, people!'

Edited By Piers Bowlan on 21/11/2018 17:57:06