NigelOnDraft

suninmyeyes - excellent post, especially the second para about us not saying half of what really goes on, since we just then get attacked by all the MS FSim experts

NoD

wiggy

suninmyeyes...second paragraph,, sadly it will be lost in the noise

remarkablebean

suninmyeyes - you've just written my retort for the next wanton comment I get...which may well be tomorrow night at work
Good stuff

Sorry I can't afford the ghost writing fees.

In the meantime, can those who don't have a clue just be thankful Messrs Burkhill and Coward did.

Roseland

Is it a fact that the port wing probe is at the coldest point in the fuel's route from tank to engine?

If the pipework - for example in the pylons - could be colder, then any tests based on bulk fuel temperature would be optimistic.

BlueRay

bae146 is clearly stating that at british airways the water sump checks were never carried out, just stamped as being done. I recall earlier in this post baengineering saying the same thing! Clearly water was building up in this centre tank from poor maintenance practice that was widespread at cc.

All i can say is the sooner the media gets this out to the wider public the better. Also why has ba lied in the report? Making out they were doing a study on water sumping just before the incident! It would be amusing if the gravity of the situation were not so significant. A large aircraft nearly down over london.

Any other ba engineers wish to comment?

sispanys ria

And here is what is written in the AAIB report:

Probably that the FO didn't have 18 years of 747 behind him... but to me THIS is how he saved the day...

To dxzh:

Thank you for your gentleman's post. I really appreciated your comments and your open minded point of view. I'm sorry not to elaborate more on it as it is bedtime but you made your way to convince me.

Jumbo Driver

Well said Rainboe! Similar to you, I have some 23 years' experience on wide-bodies and nearly 30 years on four-engine jet transports and I can see a massive contrast between the opinions from the informed professionals and that of some of the inexperienced wannabees. I have been lurking for most of this thread, just amazed at some of the uninformed rubbish that has been posted - suninmyeyes, you are spot on with your recent post.

dxzh has some very sensible and constructive ideas to put forward - especially the recent response to sispanys ria, which was excellent reading - and suninmyeyes' subsequent comment says it just the way it is.

On the subject of the recent AAIB Interim Report, I congratulate them on a detailed and comprehensive update on the progress of the investigation. I, for one, have total confidence in their competence as an investigative body.

Now, back to lurking on this thread ...


JD

Rainboe

33333333333333333333

philipat

BlueRay:

This misinformation is based on earlier misinformation and provides a good example of why many professionals will no longer contribute.

Firstly, the posts you are referencing did not refer to specific procedures which had been signed-off without implementation. Secondly, they were clearly from someone with an axe to grind, probably a disaffected (Ex?) employee.

I suggest that before you start reaching such conclusions you read the entire thread. This would give a much broader understanding and would allow you to judge the quality and credibility of individual posts within the bigger picture.

sispanys ria

Dear, I think I sent you enough PMs to tell you that nobody here recommended to push the nose down. But since you only listen to experienced people, I understand my words didn't reach your brain. What you are now saying is EXACTLY what I told you in my PM: holding attitude (also meaning AOA and speed). Unfortunately the crew didn't have an opportunity to understand the situation before they loose too much of speed and the consequence is that they left the AP until stick shaker...
I'm sure you are experienced enough to understand that letting the AP following the GS is exactly the contrary of what you recommend: the AP didnt' hold the attitude but increased it up to 14 degrees nose up.

Once again I agree... while this is what was done... and that it contributed to increase the attitude to follow the GS (what you do not recommend as an experienced heavy jet pilot).

Sadly your 18 years experience didn't taught you how to hold control over your words. You should read dxzh's post, you would learn a lot on how to share a different point of view.


This is exactly what the FO did at 170 ft... Please note that this nose down input is the consequence of letting the AP increase the attitude till stall...

Basically they did all the contrary of what you recommend (as an experienced heavy jet professional) :

They didn't hold the attitude
They did retract the flaps
They made a nose down input at low speed/altitude

As dxzh said very nicely, it's too bad that the newspaper needs to decide wether the crew made it right or wrong. In most cases, the truth is in between and we (as experienced professional) should be able to understand it clearly. It is absolutely not a matter of judging the crew, since they obviously are not the cause of the accident. Still, their actions could be analyzed for the sake of safety in finding how their actions could have been improved. According to Rainboe's attitude, I guess there wasn't so much of CRM during his 18 years of heavy 747 operations...

Loose rivets

There has to be some definition of 'pushing' or letting the nose down. It just can't have been a very pronounced maneuver.

Any attempt to sustain 14 degrees up as the speed came back towards the shake would be catastrophic, obviously. Somehow, that had to be corrected, and one would hope by just allowing the nose to come down a bit...accepting going below the glide, and trying to nail an attitude that was a last-ditch compromise.

I'll leave the flap setting out of the equation, as it may or may not have been just being part of that compromise.

scrivenger

Suninmyeyes I completely agree with your sentiments as expressed in para 2, however and very sadly there will always be professionals and professionals, so its not always that easy to leave it to the professionals....

On another note a quick question. Does the 777 fuel tank contain sensors for ice as well as water?

Swedish Steve

Each tank has a water sensor. This works by sending a signal down through the fuel which is reflected off the tank bottom surface. The time the signal takes to make the journey is measured. If there is water or ice in the tank the signal will be reflected from the fuel/water (or ice) interface. The resultant shorter signal journey will trigger the water in fuel maint message. So yes the water sensing system will react to ice as well as water.


But retracting the flaps from 30 to 25 will only take a couple of seconds, and they had all hydraulics working so no loss of hyd pressure.

BOAC

I would dearly love this sniping between factions to stop! I said eons ago on this thread that I do not know what I would have done in that situation.

As I said before, given a significant loss of available energy on the approach (as any pilot, powered or glider should know) there is an altitude above which it is beneficial to reduce flap and/or lower the nose to maintain best glide performance. There is an altitude below which is is beneficial to use the remaining energy to 'stretch' the glide. They, deliberately or inadvertently, chose the second. I suspect that at the moment of stick shake and a/p disconnect at 170' there was an awkward feeling that the choice may not have been right. All said and done, no-one died and the aircraft crashed on the airfield.

However, we cannot judge with the information we have available. I sincerely hope that some sort of 'official' analysis is produced somewhere of the 'best' solution so that it can be added to that mysterious store of 'background' knowledge all pilots have. Until then, rantings about stuffing the nose down, hydraulics being sucked dry are pointless.

Jumbo Driver

Hear, hear!


JD

NigelOnDraft

For all the bitching about the "attitude" / "GS" / "Speed".

Firstly, by leaving the AP in, you had 2(3) crew to discuss/action the best options in resolving the real problem, which lay in the engines...

For those of you who advocate lowering the nose to maintain the approach speed (~140K) the aircraft would have ended up well short* - unless you can also show us the profile as to when to now raise the nose / sacrifice airspeed.

The Flaps were retracted ~240' (IIRC) from 30 to 25. The 30 setting is almost all drag. I suspect this was inspired - the rate of loss of IAS would have been higher with Flap 30, so the stall / stick shake / end point would again have been earlier*.

I guess that with idling engines, a suitably trained and pre-notifed crew, it could be shown to have got to the threshold before landing. Lower nose, Flaps 25 (maybe 20?), even some ground effect - but it is barking mad to even suggest this crew should have tried it Contrary to the emergency handling procedures we are all taught, and irrelevant as a "lesson" because next time it occurs 1NM further out on the approach all would change and it would not make the threshold*

The actions by this crew just got the aircraft over the A30 and onto wet / soft ground, and "landed" with a tolerable RoD that saved everybody.

*Now just go and look at the A30, traffic, and the trees along the SE side. If the aircraft had come down before there, or even "over" the road / trees at very low altitude, the results would likely have been catastrophic...

NoD

PS suggest we do not even discuss the Sim here - I really cannot believe it is accurately modelled for engines out / ground effect etc.

scrivenger

Swedish Steve thanks for the reply - the point I'm trying to clarify in my head is that will the sensor react differently to water than ice . It has been discussed quite openly that the water was a contributing factor after it had melted from ice, my point being that it appears that excessesive water in the tanks can be detected as a cause for concern but not neccesarily ice....

snowfalcon2

I tried to estimate the obstacle clearance of BA038's flight path by comparing the FDR trace and Google Earth. It appears to have crossed A30 about 5 sec before touchdown at about 100 ft height. At that point there is a low (15-20 ft?) building 50 metres from the runway centerline as well as streetlight poles.

The next significant obstacle is a group of houses 700 metres from the touchdown point, where the plane was 14 sec from touchdown at 230 ft, nose high just before the stick shaker activated.

With full respect for the crew's action in a situation they had obviously never been trained for:

The hypothetical question is, would a slightly lower faster approach, reducing the margin to the houses, have left the plane with enough additional energy to flare over the road and (presumably) come down softer than the actual 1400 fpm vertical speed?

A second question. What if the airplane would have "sounded the alarm" at the earliest possible time, which according to the trace was about 54 sec before touchdown for the right engine and 45 sec for the left, as the EEC entered "Control Loop 17"? An immediate flap retraction to 20 degrees at that early point in time might actually have given some real benefit of reduced drag, even considering the ~10 sec retraction time. But how much?

Re-Heat

Hear, hear.

NigelOnDraft

For "hypothetical" I would say "irrelevant"

So you are suggesting that if the engines give a first indication of failure in an airliner, you want the crew to ignore all drills to do with trying to restore the engines, or even determine if the warning is/are false... and dive below the G/S, retracting flaps by (?) how much. And when would you do this? VMC? IMC? AWOPS? With Terrain under the approach path?

Take a clue from the AAIB - do they seem the slightest bit interested, at this stage, in the crew actions, or why the engines stopped

And are you seriously suggesting that as a result of this accident, we should look at training crews in unanticipated double engines failures on Final Approach, or might it be better to stop the engines failing in the first place

NoD