Ask The Pilot

[jb747]

It seems though some airframe manufacturers could be more open to suggestions by the professionals who drive them.

That's probably true, though they probably argue that said professionals should be more open to change.

Is it because the French think the Airbus design is 'perfect' and the only reason issues happen, is due to pilot error, that they don't simply put in a system whereby the automatic protection laws can be overridden with one switch, without having to resort to popping circuit breakers in the heat of battle.

Whether it's true or not, it's always been claimed that the driving motive has been to make their aircraft flyable by the milkman. In some ways they have succeeded in that, though at the same time it could be argued that they have simultaneously contributed to the lowering of pilot raw skills, whilst also making aircraft that can be much more difficult to operate when something goes awry. The AB protections have almost certainly saved many lives, and it would be extraordinarily foolish to move away from any of them. But, some could probably have been implemented better.

As for a magic button...I can see why they wouldn't want that. I'd actually expect that if it did exist, it would be the cause of more trouble than it's worth. I've heard, but not ever seen confirmed, that some of the military A330s do have one, but I'm not sure of the driving rationale behind it. In any event, forcing a change to a lower law involves two switches, both of which are easy to get at in the overhead panel...no cbs required.

AF447 was not caused by the control laws. The aircraft did everything it was asked to do...but sadly the person doing the asking didn't realise just what he was asking. Air Asia, nobody knows yet, but my expectation is that it was a perfectly flyable aircraft.

 

[Altair]

ETOPS will affect it, but I don't know what the NZ authorities have approved the 777 for. The approvals are so long on some of the aircraft that there aren't many places they can't go.

CAA has approved the NZ 777-300ER for 330 EDTO although NZ does not operate them above 240 minutes as these planes were amongst the first 777-300ER delivered new with 330 capabilities.
NZ has or is in the process of installing the required 240+ equipment eg. fire suppression, in the 4 777-200ERs that they own, the other 4 are leased and not scheduled to be modified. CAA approval is obviously expected before December.

 

[mjt57]

Is it defaming, or making comments based on previous investigations?

In other parts of the world, do they engage prosecutors to investigate any criminal acts so early into a crash investigation, such as what the French have done here?

Germanwings plane crash: pilot locked out of coughpit

The last para in particular...

"Meanwhile, prosecutors in Marseille, who have been charged with a separate criminal inquiry into the crash, could not immediately be reached for comment. Brice Robin, the Marseille prosecutor, was due to meet Thursday morning with the families of the crash victims."

 

[rtyuiop]

Given the (still too early to be sure of IMHO) news coming that make it sound like a very tragic murder/suicide, my guess is the French got a prosecutor involved as soon as they had internal indications that might be the case... By the sounds of it, very shortly after someone listened to the CVR.

Man... If this is the case, it's hitting me harder than other recent disasters - despite knowing intellectually it's happened before. Comes close to unthinkable...

 

[TomVexille]

Given the (still too early to be sure of IMHO) news coming that make it sound like a very tragic murder/suicide, my guess is the French got a prosecutor involved as soon as they had internal indications that might be the case... By the sounds of it, very shortly after someone listened to the CVR.

Man... If this is the case, it's hitting me harder than other recent disasters - despite knowing intellectually it's happened before. Comes close to unthinkable...

I believe that the French treat any aviation incident as a criminal investigation first, and as an aviation one second, so the prosecutor would have been involved from the get go.

 

[eric2011]

Man... If this is the case, it's hitting me harder than other recent disasters - despite knowing intellectually it's happened before. Comes close to unthinkable...

I agree. Our existence on this planet, is, at times very fragile.

RIP to all the victims of this (if correct) terrible crime

 

[cambriamarsh]

Is it defaming, or making comments based on previous investigations?

FWIW, I come from an Italian background and do not see the comments as racist.

They're not racist, they simply reflect a different balance between the importance of accountability and acceptance that learnings from incidents are more important.

 

[QF029]

There is no simple way of avoiding this. Someone with a bit more skill than a low hour cadet could make an aircraft unflyable in seconds, no matter who else was in the coughpit.

JB are you comfortable elaborating on this? Are you saying that a co-pilot could make changes in the coughpit in your presence and they would be irreversible? Because they could be so subtle?

 

[Awesom Andy]

JB are you comfortable elaborating on this? Are you saying that a co-pilot could make changes in the coughpit in your presence and they would be irreversible? Because they could be so subtle?

I can I can put it this way... when I was a student pilot, if I made a sudden kamikaze style movement, and jumped onto my instructor, we would most likely end up with a wreckage...

 

[jb747]

JB are you comfortable elaborating on this? Are you saying that a co-pilot could make changes in the coughpit in your presence and they would be irreversible? Because they could be so subtle?

Of course I'm not going to elaborate upon this. But pretty well every solution I've heard bandied around so far is nothing short of a totally pointless exercise, which has no intent other than giving an appearance of doing something.

 

[anat0l]

Of course I'm not going to elaborate upon this. But pretty well every solution I've heard bandied around so far is nothing short of a totally pointless exercise, which has no intent other than giving an appearance of doing something.

Apparently the appearance of doing something is just as good, if not good enough. Inaction, albeit considered inaction, is seen as gross negligence.

Anyway, this post should really be in the other thread...

 

[RooFlyer]

Hope people don't mind me bumping a question I posted up-thread which got over-run by the germanwings incident. May as well re-paste it here rather than linking back.
________

I recently saw a replay of the Four Corners rendition of the QF32 incident and investigation. It reminded me of something I wondered when I first saw it, and also the 'Air Crash Investigation' portrayal.

I obviously take these with several grains of salt, but both stated one conclusion from the investigation in pretty much the same way.

That is, the oil pipe broke, spraying oil on very hot components of the engine. A fire broke out, and this fire heated/soften/affected the turbine disc (and other components) and this ultimately caused the turbine to spin faster than design, to ultimately fail and fly apart.

The time between the fire starting and the failure and then the 'uncontained failure' (AKA 'explosion') wasn't mentioned, but I imagine it must have been at least some seconds, to heat the turbine disc, then affect its performance and then ultimately fail.

My question is - if the time between the fire and the 'explosion' was any more than a second or so, why would there not have been an engine fire alarm, as the first indication that something was amiss, rather than the "boom ... boom" that RdC reported? (Put another way, how long would you expect between such an oil fuelled engine fire and an alarm sounding?) Can anyone enlighten me what the time between the start of the fire and the failure was estimated to be (I know I could look up the report, but I ask in the context of my main question)?

 

[jb747]

Hope people don't mind me bumping a question I posted up-thread which got over-run by the germanwings incident. May as well re-paste it here rather than linking back.
________

I recently saw a replay of the Four Corners rendition of the QF32 incident and investigation. It reminded me of something I wondered when I first saw it, and also the 'Air Crash Investigation' portrayal.

I obviously take these with several grains of salt, but both stated one conclusion from the investigation in pretty much the same way.

That is, the oil pipe broke, spraying oil on very hot components of the engine. A fire broke out, and this fire heated/soften/affected the turbine disc (and other components) and this ultimately caused the turbine to spin faster than design, to ultimately fail and fly apart.

The time between the fire starting and the failure and then the 'uncontained failure' (AKA 'explosion') wasn't mentioned, but I imagine it must have been at least some seconds, to heat the turbine disc, then affect its performance and then ultimately fail.

My question is - if the time between the fire and the 'explosion' was any more than a second or so, why would there not have been an engine fire alarm, as the first indication that something was amiss, rather than the "boom ... boom" that RdC reported? (Put another way, how long would you expect between such an oil fuelled engine fire and an alarm sounding?) Can anyone enlighten me what the time between the start of the fire and the failure was estimated to be (I know I could look up the report, but I ask in the context of my main question)?

Between the time the aircraft took off, and the engine failure, was almost exactly 3 minutes. I don't know that they know exactly when the pipe cracked and the fire started. It could have been during the take off roll, or shortly after. The disc itself wasn't heated, but rather the shaft that connects it to the compressor end of the engine. Once the shaft failed, it was no longer able to transfer the enormous amount of power that it was catching to the compressor, to it simply accelerated...until it failed due to massive overspeed. That would have taken perhaps a couple of seconds.

The fire sensors are not everywhere in an engine. For obvious reasons, parts of a jet engine are actually on fire at all times anyway. The sensors basically tell you that some part of the engine which is normally cold is much hotter than usual. I don't know that it would be reasonably possible to have sensors in the part of the engine where the failure happened.

Apart from engineering changes to the engine, the FADECs were changed after this event to enable them to more quickly sense and react to a shaft failure and overspeed. If they could be quick enough, the event would stop at the shaft failure stage...so it would remain a 'simpler' event.

 

[blu]

Are "power to weight" ratios similar?
Why does a 767 lift off in a much shorter distance than a 747?
I remember a takeoff on a fully loaded JL 747 (was ski season) that seemed to need every metre on the SYD runway (if thats possible),

 

[RooFlyer]

Thank-you jb747. Clearer now.

 

[ChasingDaylight]

I've just been looking at the various routes of my upcoming trips on FR24. I've noticed that on DXB <-> LHR legs, that Iraq is given a wide berth by QF(10) somewhat consistently over the past few days (haven't gone any further back than that but probably has been doing so for some time). Is this due to the security situation on the ground in Iraq or to deconflict with the various coalition aircraft operating there?

 

[Himeno]

I've just been looking at the various routes of my upcoming trips on FR24. I've noticed that on DXB <-> LHR legs, that Iraq is given a wide berth by QF(10) somewhat consistently over the past few days (haven't gone any further back than that but probably has been doing so for some time). Is this due to the security situation on the ground in Iraq or to deconflict with the various coalition aircraft operating there?

There was a public (media) uproar a few months back that airliners were overflying Iraq and Syria. Most airlines responded by rerouting flights over Iran.

 

[Captain Halliday]

If they could be quick enough, the event would stop at the shaft failure stage...so it would remain a 'simpler' event.

Should this ever be achieved by engineers, would it therefore be a "simpler and fairer" contained engine failure?

 

[jb747]

The twins all have better power to weight ratios than do the quads. The simple reason is that a twin (737,767, 330, etc) can have a single engine fail, and it will lose half of the available power, but it still has to be able to fly away from V1 on the runway. In the four engined aircraft, the failure of a single engine, only removes a quarter of the power, so it does not need anywhere near as much 'excess' power in the all engine case. The quads won't fly away in most cases of loss of a second engine on the runway.

The 767s, in particular the QF 767 GEs, were all purchased for medium haul operations, and as such their maximum weights were up around 180 tonnes. But, they ended their lives doing domestic duty, where the weight was around 120 tonnes. If they had been purchased for that work, they could have used less powerful engines.

 

[jb747]

Should this ever be achieved by engineers, would it therefore be a "simpler and fairer" contained engine failure?

That would be the expectation.