Gimli Glider

[Guest basscheffers]

That is a scary thought. Where is the override in the computer program??

Why is that scary? An all-engine out where this is needed happens how often? You reckon this is going to affect anyone you know at any time.

More computer control has made aircraft safer. As they say: lies, damn lies and statistics...

 

 

[eightyknots]

Why is that scary? An all-engine out where this is needed happens how often? You reckon this is going to affect anyone you know at any time.More computer control has made aircraft safer. As they say: lies, damn lies and statistics...

The scary thought is that, had the Gimli Glider been an Airbus, many lives would have been lost on that day. All this due to the override of the Pilot In Command by the inanimate "computer-in-command" fitted by Airbus Industries.

 

An all-engine out situation has to be engineered into the equation despite the fact it is indeed a rare occurence. That is the reason why Boeing fitted RAM technology in the unlikely event of a complete loss of all engine power. That little propellor kept the hydraulic system operational and this allowed the pilots to continue to be 'in command' of the aircraft on that fateful day. Had the Boeing engineers developed an alternative mindset (i.e. "that no allowance is necessary in the design process for an all engine out occurrence because this rarely happens") aviation history would have recorded a bloodbath incident at Gimli instead.

 

I still feel there should be a 'red-button' override of Airbus' computer in exceedingly unusual circumstances such as this.

 

BTW, I am booked to fly on a Jetstar flight tomorrow. It will be an Airbus. Do I feel unsafe about this? No.

 

 

[dazza 38]

FWIW not all a/c can be sustained into a slid slip or more to the point loading up the vertical Stabiliser With side loads.Classic eg is that I know of is a 737 that lost its verticle stabiliser due to the pilot being taught/maybe to use full deflection of the rudder (each way) when in wake turbulence.The full deflection caused the Vertical Stabilizer to depart company with the A/c.Also A B52 lost a Vertical Stabilizer during low level Tact flying .(Why a B52 was doing low level work has got me F*^^%) Anyway they lived to fly another day.737 crew and passengers didnt.

 

I know there is a difference between holding a side load (side slip) and kicking peddals each way and loading up each side of the vert stabilizer depending of the rudder deflection.But they are not as strong as people thing they are.IMO

 

 

[Guest basscheffers]

The scary thought is that, had the Gimli Glider been an Airbus, many lives would have been lost on that day.

First of all, that is far from certain! Knowing they couldn't side slip at the last minute, they might have increased their descent earlier. Again: an Airbus *has* been through this and all on board lived.

 

That is the reason why Boeing fitted RAM technology in the unlikely event of a complete loss of all engine power.

It's called the RAT (Ram Air Turnbine) and all Airbusses have them.

 

aviation history would have recorded a bloodbath incident at Gimli instead.

You have a vivid imagination!

 

BTW, I am booked to fly on a Jetstar flight tomorrow. It will be an Airbus. Do I feel unsafe about this? No.

Yet you are looking at building your own aircraft? The airbus flight you are about to undertake is the safest mode of transport by far. Homebuilts are one of the most dangerous.

You might want to rethink your plans!

 

 

[Exadios]

It depends. I would not start turning anywhere (and loose height and thus options) without knowing if the options would get any better. That does leave the possibility of missing out on the option behind you, which may be gone by the time you work out it would have been best. Damned if you do, damned if you don't. I would not hold his decision making against him.Again, the guys trying in the sim had nothing to loose. What if Sully did immediately try to turn back and didn't make it? He'd have killed hundreds of people in the aircraft and on the ground!

When the engines fail the best option is to land and the safest place to land is on a runway designed for the purpose. There are no better options.

 

Why do you think he would he not make the runway?

 

As I understand the incident the crew did not start selecting landing options until after the engines failed. The time to make that decision is before the engine failure.

 

 

[Exadios]

FWIW not all a/c can be sustained into a slid slip or more to the point loading up the vertical Stabiliser With side loads.Classic eg is that I know of is a 737 that lost its verticle stabiliser due to the pilot being taught/maybe to use full deflection of the rudder (each way) when in wake turbulence.The full deflection caused the Vertical Stabilizer to depart company with the A/c.Also A B52 lost a Vertical Stabilizer during low level Tact flying .(Why a B52 was doing low level work has got me F*^^%) Anyway they lived to fly another day.737 crew and passengers didnt.I know there is a difference between holding a side load (side slip) and kicking peddals each way and loading up each side of the vert stabilizer depending of the rudder deflection.But they are not as strong as people thing they are.IMO

Interesting. It is a bit of a worry to know that it is possible to rip the rudder off in flight.

 

My guess as to why the B52 was at low level is because flying at 500' AGL is one of their tactics.

 

 

[Spin]

Interesting discussion, especially as I'm shifting some taped programs around and watching the Hudson incident at the same time. Very easy to sit behind a keyboard and pontificate, however I suspect that when your ass is on the line and you're having to process an almost unbelievable situation, it all looks a little different. There are plenty of examples of pilots who were not able to adapt fast enough and ended up killing themselves and passengers - I am more than happy to tip my cap to someone who performs above and beyond.

 

I'm happy to fly either Boeing or Airbus, but have to say that I prefer the Boeing approach - Airbus reads a bit like, "never mind, we know best so just do it our way..." all very well until the unimaginable happens,..... yet again! Personally I'd like a pilot to have a chance to exercise some stick n rudder skills in extremis and when all else fails.

 

 

[GDL]

EightyKnots, you are right about the US needing to be part of the change to metric. Having lived beside to the 'sleeping giant' all my life, they have had a huge influence on such things as aviation. Canada has changed much of the rest of its old imperial world but it has been a difficult effort, since the US seems destined (desires?) to be the last man standing in the imperial world. The country as a whole is inherently conservative in many ways. Glass cockpits? I am not sure that would solve the problem but you could be right there as well. I know I was in Poland and Portugal and almost all use metric when flying. We need rationality. But are we ration as a world?

 

 

[eightyknots]

It's called the RAT (Ram Air Turnbine) and all Airbusses have them.

Sorry, my typing error, I stand corrected.

 

I appreciate that Airbus aircraft have RATs on board (don't tell the passengers!). However, if the Pilot In Command is unable to control the plane in an extreme situation (due to the Computer in Command's override instructions), the RAT's usefulness is significantly diminished. I still maintain that, in a serious situation, the Pilot should be able to override the computer even to the point of side-slipping the Airbus as the Boeing pilot did at Gimli.

 

 

[Guest Maj Millard]

Well said Eighty-knots, my view exactly.

 

Dazza, The one that lost it's tail in wake turbulance coming out of Kennedy was an Airbus A3oo, and it was caused by the pilots excessive use of the rudder to try (incorrectly )to dampen yaw induced from the preceeding 747. Airbus have still refused to detune the rudder imputs, so concievably it could occur again.

 

All aircraft should have the capability to be sideslipped, or recovered from any, and all unplanned upsets. No good saying there's a low chance of it happening, it will ,and has happened, so what do you do then ?.... fold your arms and just die ?................I'm glad Boeing doesn't see it that way.....................................................Maj...

 

 

[facthunter]

I'm glad maj corrected the tail coming off matter. It was a pretty silly thing to have done to an aeroplane nevertheless showing little appreciation of inertia and aerodynamic loads. I don't really blame the aeroplane in that incident.

 

Most pilots prefer the Boeing philosophy where you have more of a fighting chance and seem to have more idea what the plane is doing. Both systems are made by Honeywell. I haven't flown the later airbus's but some of my friends are operating the relevant simulators, and while the sidestick models perform balanced turns there may be some way of slipping them. I will find out, because this keeps coming up.

 

GDL I thought that mob at Seattle were called the "LazyB".

 

Spin, I'm with you. The trouble with automatics and having ALL possibilities covered it never happens. ALL possibilities, cannot be anticipated by definition. The Airbus philosophy is to not trust the pilot. This could be the waste of a good resource if the pilot is well trained and experienced. If he/she isn't what are they doing there? It is an attempt to deskill the role of pilot, and while statistically you can prove that pilots can be the reason for some aeroplanes crashing, it is a giant step to go fully automatic and rely on that. Nev

 

 

[dazza 38]

Well said Eighty-knots, my view exactly.Dazza, The one that lost it's tail in wake turbulance coming out of Kennedy was an Airbus A3oo, and it was caused by the pilots excessive use of the rudder to try (incorrectly )to dampen yaw induced from the preceeding 747. Airbus have still refused to detune the rudder imputs, so concievably it could occur again.

 

All aircraft should have the capability to be sideslipped, or recovered from any, and all unplanned upsets. No good saying there's a low chance of it happening, it will ,and has happened, so what do you do then ?.... fold your arms and just die ?................I'm glad Boeing doesn't see it that way.....................................................Maj...

ScareBus hey.Thats for the correction, MAJ,

 

 

[Flying Ant]

The tail did come off an Airbus as a result of the pilots applying full rudder deflection, the aircraft was yawed then quickly the rudder was reversed which overloaded the vertical stab beyond design limits due to the side load of the airflow and the force applied by the rudder acting together. This problem is not isolated to Airbus, Boeing issued a bulletin to all operators outlining the design load capacity of the rudder and tail and pointed out that this rudder reversal technique can overstress Boeing aircraft too.

 

In the case of a engine failure due to fuel exhaustion there is not a lot of difference between and Airbus and a Boeing. In a Boeing 767, the RAT will deploy which gives enough (but not full) hydraulic pressure to the flight controls operated by the centre hydraulic system (there are 3, Left, Centre and Right). There are no electrics from the RAT so the electrical system goes into standby power from the main battery only.

 

In an A320/A330 etc... (I haven't flown one but just of off the phone to a friend who does) the rudder on an Airbus is always in direct law and an Airbus can be sideslipped just as well as a Boeing. In the case of a dual engine failure the RAT would supply hydraulics and electrics and the aircraft would be in direct law so there would be no flight envelope protection.

 

On a wider note, the notion that a Boeing is better than Airbus because you can "fly" the Boeing is rubbish. Many Boeings have been mishandled and crashed as a result of being overstreed, overspeed, stalled etc... which would have been prevented in an Airbus. On the Husdon river landing, the Captain had started the APU before losing all electrics which gave him back all his protections and he landed in normal law. This allowed him to simply flare into full back stick and let the computers maintain wings level and max alpha.

 

In the case of a dual engine failure, an A330 glides a lot better than a 767 too

 

 

[dazza 38]

Interesting. It is a bit of a worry to know that it is possible to rip the rudder off in flight.My guess as to why the B52 was at low level is because flying at 500' AGL is one of their tactics.

Hi Mate I found the Video on Utube this arvo.I first watched it while I was in the RAAF. It was Boeing doing Low level Turbulance testing. I not very computor literate.I dont know how to post it here.Its on my Facebook page. Tomo or Spin, W68 will post it here.I just have to ask them.

 

 

[Spin]

Here ya go, hope your faith isn't misplaced!

 

 

 

[Spin]

By the way, nice find Dazza, it was very interesting.

 

 

[Spin]

Tx for the info Flying Ant, must say my understanding of the control logic was a little different,ie although the rudder is in direct law, under normal circumstances (multiple failures aside) the roll control is not and the aircraft will prevent you from cross controlling.

 

Stirring aside, I have several friends who drive various models of Airbus and a recurring theme is the observation that they are hellish clever, but there is a slight unease with the fact that the aircraft does quite a bit off its own bat - fuel transfer etc. They have all become quite keen on them as familiarity has grown (ex 737 and 747 fleets) but another common observation is that there are times when you have to work around the system when things don't go exactly to plan and the "cleverness" is actually counterproductive. I did also hear a reported observation from the A380 incident that some things would in fact have been easier with a paper manual to consult rather than a computer which was ranking failures according to its own pre-programmed logic.

 

The following video does however illustrate my misgivings:stirrer:

 

 

 

[Guest basscheffers]

On a wider note, the notion that a Boeing is better than Airbus because you can "fly" the Boeing is rubbish. Many Boeings have been mishandled and crashed as a result of being overstreed, overspeed, stalled etc... which would have been prevented in an Airbus.

Good to hear that from a Boeing pilot! :D A good example is the 757 slamming into the Andes. (http://en.wikipedia.org/wiki/American_Airlines_Flight_965) It is speculated that a FBW Airbus would have automatically retracted the speed brakes in the scenario and would have been more likely to make it over the mountains.

Really, all I personally care about is accident rates, not particularly how they are caused by any one type of aircraft. And the good thing is: the computers will keep getting better every generation. Pilots won't! In the mean time: current generation aircraft of both manufacturers seem to be as safe as each other.

 

The majority of early A320 accidents that were originally attributed by the media of computer failures all turned out to be pilot error just like most other crashes. Of course the media had moved on by that point and the original believers just called it a conspiracy...

 

Now I am waiting on the AF447 flight recorders to be found, the ruling to be it was indeed pitot ice that was the major factor, and then hear all the Boeing fanboys shout how the direct control in a Boeing would have enabled the crew to recover from the upset. (with no such training, at night and in a thunderstorm, I might add.)

 

 

[Guest basscheffers]

The following video does however illustrate my misgivings

That investigation concluded pilot error. He was simply too low, too slow, at alpha max and there simply wasn't enough time for the engines to spool up.

They tried and tried in the sim and then in real life to trick the Airbus into thinking it was landing (the media version of the story) but couldn't.

 

Unfortunately, it is still the first example people still bring up of Airbus computer failings, when there is none.

 

 

[dazza 38]

By the way, nice find Dazza, it was very interesting.

Thanks Carl For Posting here. I watched in the 1989 during my tech training.I just tried U tube and it was on it.It goes to show that nothing is as it seems at times.Remember B52's are old now, but this was taken a loooong time ago.

 

 

[Spin]

Ugh, do we really have to descend to the level of the schoolyard? Boeing fanboys..... really?

 

Be aware that the accident investigation into the Mulhouse accident is one of the most hotly disputed around with quite a bit of evidence that the engines did not in fact respond when the throttles were pushed forward - a phenomenon experienced with this model previously but not conveyed to the Air France pilot body. As usual the truth probably lies somewhere between the versions, certainly the pilot was pushing the envelope esp with passengers aboard. Part of the problem with the investigation lies with France's legal system where the police siezed the evidence instead of specialised civil authorities (NTSB and the like) doing the investigation. They also have a punitive focus where deaths have occurred, so were more interested in finding someone to blame rather investigating potential technical explanations. Anyhow it isn't quite as open and shut as we have been led to understand.

 

 

[Guest Maj Millard]

The A330 would need to glide a lot better , they've certainly had to use it a couple of times !............................Maj...

 

 

[facthunter]

Think that's an A-300. The pilot was considered to have not had a thorough knowledge of the Auto-throttle operation. and did not get any significant power response. Moving the throttles forward did not give more power ,( as would be the normal expectation. ) .The plane was in a perfectly serviceable comdition. Hitting the Go round button would have had it go to full power, alternatively, disconnecting the auto throttle would have restored it to manual control of engine power. Big mistake.. Nev

 

 

[Flying Ant]

In relation to the A320 that flew into the trees; all high bypass engines have a significant spool up time from ilde, there is a lot of mass there that has to be accelerated and at a metered rate. That pilot was flying level with the aircraft configured for landing. He flew level waiting for alpha floor to apply TOGA thrust and it didn't because it wasn't supposed to, it was within the parameters for landing (Radio Altitude/Config). When he realised he applied TOGA thrust manually and the engines were just spooling up when he went into the trees.

 

As an aside, you'll notice it went in wings level which contributed to the survivability of the crash...

 

Don't get me wrong, fly by wire can go wrong and has it own limitations. Just ask the pilots of the QF72.

 

I'm staggered that the AF447 flight data has not been recovered. Until it is all we can do is speculate. Pitot icing is interesting because we are specifically trained how to fly with unreliable airspeed indicators so I think there is more to it than that, but there always is...

 

 

[dazza 38]

In relation to the A320 that flew into the trees; all high bypass engines have a significant spool up time from ilde, there is a lot of mass there that has to be accelerated and at a metered rate. That pilot was flying level with the aircraft configured for landing. He flew level waiting for alpha floor to apply TOGA thrust and it didn't because it wasn't supposed to, it was within the parameters for landing (Radio Altitude/Config). When he realised he applied TOGA thrust manually and the engines were just spooling up when he went into the trees.As an aside, you'll notice it went in wings level which contributed to the survivability of the crash...

 

Don't get me wrong, fly by wire can go wrong and has it own limitations. Just ask the pilots of the QF72.

 

I'm staggered that the AF447 flight data has not been recovered. Until it is all we can do is speculate. Pitot icing is interesting because we are specifically trained how to fly with unreliable airspeed indicators so I think there is more to it than that, but there always is...

So true FA, all jets take a little while to spool up.As you have mentioned By pass even more so.FWIW I only had time on P&W TF30 (F111)and time on RR fitted to the Tornado IDS RSAF jets. IMO the Tornados were light years a head of the F111 in the ease of maintenance.Cheers