2005 MD 80 crash due to overloading
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2005 MD 80 crash due to overloading
Updated: April 9th, 2007 11:37 AM EDT
French Investigators Find Overloading Contributed '05 Venezuela Crash
Associated Press WorldStream
via NewsEdge Corporation
FORT-DE-FRANCE, Martinique_An airliner that crashed in Venezuela, killing 152 tourists from the French Caribbean island of Martinique, was apparently overloaded, according to French authorities investigating the disaster.
"Apparently, the plane was too loaded to have sufficient propulsion at the altitude it was at," prosecutor Claude Bellanger said. The Aug. 16, 2005, crash also killed the eight-member Colombian crew on the chartered West Caribbean Airways jet.
French investigators on Thursday briefed victims' families on the results of analyses on the plane's flight recorders and engines. They said the two engines were working.
But Bellanger said investigators were "struck by the absence of exchanges and communication between the crew members."
He said the plane's route also was "quite troubling" because the plane flew through a storm. "Everyone knows that cumulonimbus (clouds) are very damaging for a plane," he said.
Investigations are continuing.
French, Colombian and U.S. experts have been cooperating with Venezuelan investigators, and the cockpit voice recorder was analyzed in France along with the flight data recorder.
The French investigation authority that conducted the analysis confirmed that about eight minutes before the crash, the crew discussed weather conditions and the possibility of icing, and about turning the deicers on.
Later, the crew told air traffic controllers they had a double engine failure. A ground proximity alarm sounded for the last eight seconds of the flight, then the recording stopped.
<<Associated Press WorldStream -- 04/09/07>>
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due to and contributed...well let's not mince words.
it would seem that if a plane was properly loaded and encountered icing or turbulence it could survive with average piloting ability.
IF the plane was overloaded, staggering on the edge of an aerodynamic stall at full power, AND THEN engine anti ice was selected, one of two things might happen.
1. Power/Thrust would be reduced by using the anti ice...being so close to a stall this might have been the "straw that broke the camel's back".
2. IF anti ice was selected without selecting continuous ignition of some sort, ice could melt if already formed, and go back into the engine perhaps reducing thrust, momentary flame out or something akin to that...yet not fully reported.
IF in a Cu cloud, perhaps hail or other intense or extreme precip helped rob lift from the wings.
I have seen reports of a USA domestic MD80 going too high for its weight...firewall power for 8 minutes would not accelerate the plane...a loss of some 8000 feet was required to regain control.
Imagine the same thing while inside of a storm, at night...anti ice on robbing even more power from the engines.
And this could happen to any plane...not just the MD80.
overload, too high for weight, icing, use of anti ice, pushing an airplane out of the envelope...take your pick
it would seem that if a plane was properly loaded and encountered icing or turbulence it could survive with average piloting ability.
IF the plane was overloaded, staggering on the edge of an aerodynamic stall at full power, AND THEN engine anti ice was selected, one of two things might happen.
1. Power/Thrust would be reduced by using the anti ice...being so close to a stall this might have been the "straw that broke the camel's back".
2. IF anti ice was selected without selecting continuous ignition of some sort, ice could melt if already formed, and go back into the engine perhaps reducing thrust, momentary flame out or something akin to that...yet not fully reported.
IF in a Cu cloud, perhaps hail or other intense or extreme precip helped rob lift from the wings.
I have seen reports of a USA domestic MD80 going too high for its weight...firewall power for 8 minutes would not accelerate the plane...a loss of some 8000 feet was required to regain control.
Imagine the same thing while inside of a storm, at night...anti ice on robbing even more power from the engines.
And this could happen to any plane...not just the MD80.
overload, too high for weight, icing, use of anti ice, pushing an airplane out of the envelope...take your pick
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'Due to' vs. 'contributed'
'Due to' would denote the primary cause of something. 'Due to my low test score I was not selected.'
'Contributed' denotes something that also caused the event but was not the primary cause. 'A bad case of nerves contributed to my scoring very low on the test.'
Usually accident reports try to give a primary cause for an accident but also show contributing factors. It's often a matter of judgment whether something is one or the other.
'Contributed' denotes something that also caused the event but was not the primary cause. 'A bad case of nerves contributed to my scoring very low on the test.'
Usually accident reports try to give a primary cause for an accident but also show contributing factors. It's often a matter of judgment whether something is one or the other.
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barit1 I think you are quite right
as to "due to" or "contributed" feel free to read whatever you want into it.
just don't fly too high for your weight.
as to "due to" or "contributed" feel free to read whatever you want into it.
just don't fly too high for your weight.
In some respects (too high, too slow) doesn't this resemble the Pinnacle CRJ accident?
My understanding of the differences between the two events was that the Pinacle recovery was aborted by the unfamilarity with the engine restart procedures, while the MD80 was the inability to recover from an aircraft stall condition.
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Overloading?
Initial reports were the pilots reported engine problems and possible ice on their wings. How could you overload an MD82 on that short of a flight? Maybe they climbed too high in icing conditions but how can you call that overloading? That aircraft has to be handled very carefully above FL350 as far as weight and speed. We were light but got too slow one day above 36,000 trying to get above the clouds and even with max power lost a lot of altitude to get out of low speed buffet.
Initial reports were the pilots reported engine problems and possible ice on their wings. How could you overload an MD82 on that short of a flight? Maybe they climbed too high in icing conditions but how can you call that overloading? That aircraft has to be handled very carefully above FL350 as far as weight and speed. We were light but got too slow one day above 36,000 trying to get above the clouds and even with max power lost a lot of altitude to get out of low speed buffet.
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This one has to be down to training and resultant situational awareness.
At that height, the margin between sustained levitation and the onset of pre-stall conditions is minimal.
One would think the PIC would ram the yoke forwards -before or in tune with the stick shaker.
But, unless you have actually studied all the manifestations of the deep stall - ans all the factors that create and affect it, it is unlikely that you will be quick enough to recognise it in time.
Sim training can never really show the vagaries of T tail type behaviour -can it?
Even that maestro GP John Cunningham had a Trident go unexpectedly nose up on him in testing- and "waited an age" for it to decide to come down and not rear-up on him.
So, are we looking at an MD long body T tailer at the edge of the high altitude / high weight flight performance envelope that simply fell over backwards too damn quick for the chaps up front to fight?
A quick look at the wreckage photos show the classic deeps tall impact- low fwds airspeed, nose up, high descent rate.
I think we know how that happened - too slow!
At that height, the margin between sustained levitation and the onset of pre-stall conditions is minimal.
One would think the PIC would ram the yoke forwards -before or in tune with the stick shaker.
But, unless you have actually studied all the manifestations of the deep stall - ans all the factors that create and affect it, it is unlikely that you will be quick enough to recognise it in time.
Sim training can never really show the vagaries of T tail type behaviour -can it?
Even that maestro GP John Cunningham had a Trident go unexpectedly nose up on him in testing- and "waited an age" for it to decide to come down and not rear-up on him.
So, are we looking at an MD long body T tailer at the edge of the high altitude / high weight flight performance envelope that simply fell over backwards too damn quick for the chaps up front to fight?
A quick look at the wreckage photos show the classic deeps tall impact- low fwds airspeed, nose up, high descent rate.
I think we know how that happened - too slow!
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As I have said many times on this form, and others, we won’t know much about what actually happened until the facts are made known. Unfortunately, sometimes the facts get obscured with other priorities and sometimes because of who is “running” the investigation, some of the things that are said to have “contributed” to the accident were actually more involved than just “contributing” and sometimes things that are said to have “caused” the accident didn’t have anything to do with what really caused the accident. While we all hope that politics can be left out of such things, I think everyone here is smart and savvy enough to recognize that such is just not “the real world.”
As for the DC-9 itself … it was designed to have a wider horizontal stabilizer than the BAC1-11 (which was notorious for “deep stall” characteristics) purposefully to bring a couple of feet of the elevator out from the wing stall blanking area on each side, into a “more undisturbed” portion of the slipstream. Also, the DC-9 was designed with a hydraulically powered elevator that would port 3000 psi of hydraulic pressure to bring both elevators to the full nose down position with full forward control column movement. Does this guarantee that a deep stall could be avoided or, if inadvertently encountered, could be escaped from? Certainly not. However, it does give the flight crew a chance of recovering from something that previous T-tailed birds (like the BAC1-11) could not.
There are two additional things to consider as well. One: at least theoretically, except in the most deep of deep stalls, there should still be some aileron effectiveness that would allow the flight crew to roll the airplane toward a horizon and allow the nose to fall. Of course, admittedly, that would take presence of mind – and who knows if this is something with which this crew had none, some, enough, or an abundance. Two: human nature is human nature. I have seen, more than once, when the airplane is nose high and descending – either in a stall or painfully close to one – the pilot flying is sometimes reluctant to release the back pressure on the controls (let alone push forward on the controls) for fear that a downward acceleration would result and make things worse – at least from his/their perspective – and descending at a higher rate (even for only a brief period) might be considered by someone without a lot of “presence of mind” to be a more negative situation.
The bottom line? We'll have to wait until a LOT MORE information (hopefully factual information) is made available.
As for the DC-9 itself … it was designed to have a wider horizontal stabilizer than the BAC1-11 (which was notorious for “deep stall” characteristics) purposefully to bring a couple of feet of the elevator out from the wing stall blanking area on each side, into a “more undisturbed” portion of the slipstream. Also, the DC-9 was designed with a hydraulically powered elevator that would port 3000 psi of hydraulic pressure to bring both elevators to the full nose down position with full forward control column movement. Does this guarantee that a deep stall could be avoided or, if inadvertently encountered, could be escaped from? Certainly not. However, it does give the flight crew a chance of recovering from something that previous T-tailed birds (like the BAC1-11) could not.
There are two additional things to consider as well. One: at least theoretically, except in the most deep of deep stalls, there should still be some aileron effectiveness that would allow the flight crew to roll the airplane toward a horizon and allow the nose to fall. Of course, admittedly, that would take presence of mind – and who knows if this is something with which this crew had none, some, enough, or an abundance. Two: human nature is human nature. I have seen, more than once, when the airplane is nose high and descending – either in a stall or painfully close to one – the pilot flying is sometimes reluctant to release the back pressure on the controls (let alone push forward on the controls) for fear that a downward acceleration would result and make things worse – at least from his/their perspective – and descending at a higher rate (even for only a brief period) might be considered by someone without a lot of “presence of mind” to be a more negative situation.
The bottom line? We'll have to wait until a LOT MORE information (hopefully factual information) is made available.
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air rabbit is quite right about the dc9/md80 elevator hydraulic ram...indeed , prior to takeoff this is a required check.
I have seen a disregard of height/weight concerns in recent years...also the least conservative buffet margin speeds/altitudes etc.
higher- more fuel efficient...but not always safer.
recently, in the USA, an allegiant MD80 took off overloaded...weight and balance data apparently ammended AFTER TAKEOFF...plane couldn't go to planned altitude for cruise, insufficent fuel for lower altitude flight...return to field. (all info is very preliminary and has not been verified by the FAA or NTSB...this is apparently what MIGHT have happened)
it is quite easy to be overloaded and not know it...and even more so in the aviation third world
I have seen a disregard of height/weight concerns in recent years...also the least conservative buffet margin speeds/altitudes etc.
higher- more fuel efficient...but not always safer.
recently, in the USA, an allegiant MD80 took off overloaded...weight and balance data apparently ammended AFTER TAKEOFF...plane couldn't go to planned altitude for cruise, insufficent fuel for lower altitude flight...return to field. (all info is very preliminary and has not been verified by the FAA or NTSB...this is apparently what MIGHT have happened)
it is quite easy to be overloaded and not know it...and even more so in the aviation third world
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Weight errors could potentially be caught by measuring acceleration during the takeoff roll - the IRS accelerometers could serve nicely. This can also sense low thrust, dragging brakes, anything else throwing off the a=F/m relationship.
Weight AND balance errors could presumably be caught by LG strut pressure measurement; some systems have been tried over the years but I know of none that is reliable.
Alas, we are not yet ready for the 21st century.
Weight AND balance errors could presumably be caught by LG strut pressure measurement; some systems have been tried over the years but I know of none that is reliable.
Alas, we are not yet ready for the 21st century.
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apparently adverb [ sentence adverb ] as far as one knows or can see : the child nodded, apparently content with the promise. Used by speakers or writers to avoid committing themselves to the truth of what they are saying
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Hm
Too much writing about all but facts.
Overloaded or not would have hardly changed anything !
On that altitude there may exist ice particles...
but hardly any ICING for wings or engines.
And because pilots DISCUSSED whether or not use de-icing ONLY proves the above.
However ice dust is absolutely harmless to engines and whole aircraft .....
it is can sometimes be very NASTY to PT2 signal, if Engine Anti Ice was NOT switched ON.
PT2 probe can get filled/BLOCKED with ice dust, now, its signal would change so
that pilots indicators for engine thrust (EPR, either left or right or both)
would start INDICATING HIGHER thrust (another words giving false indications),
and even much above max limit.
As in any normal operation, the ATS (AutoThrotlle) would be on, it would tend to "reduce" thrust to MAX Cruise EPR (or whatever EPR was selected on TRC),
thus ACTUALLY reducing (TRUE) thrust EVEN to IDLE, while pilot's eyes would be "happy" with "MAX" power selected.
(Actually seen few times in climb and cruse.)
For all else, please read what has happened in the cockpit, from top FL to ground.
Cheers
G.G.
Overloaded or not would have hardly changed anything !
On that altitude there may exist ice particles...
but hardly any ICING for wings or engines.
And because pilots DISCUSSED whether or not use de-icing ONLY proves the above.
However ice dust is absolutely harmless to engines and whole aircraft .....
it is can sometimes be very NASTY to PT2 signal, if Engine Anti Ice was NOT switched ON.
PT2 probe can get filled/BLOCKED with ice dust, now, its signal would change so
that pilots indicators for engine thrust (EPR, either left or right or both)
would start INDICATING HIGHER thrust (another words giving false indications),
and even much above max limit.
As in any normal operation, the ATS (AutoThrotlle) would be on, it would tend to "reduce" thrust to MAX Cruise EPR (or whatever EPR was selected on TRC),
thus ACTUALLY reducing (TRUE) thrust EVEN to IDLE, while pilot's eyes would be "happy" with "MAX" power selected.
(Actually seen few times in climb and cruse.)
For all else, please read what has happened in the cockpit, from top FL to ground.
Cheers
G.G.
However ice dust is absolutely harmless to engines and whole aircraft .....
it is can sometimes be very NASTY to PT2 signal, if Engine Anti Ice was NOT switched ON.
PT2 probe can get filled/BLOCKED with ice dust, now, its signal would change so
that pilots indicators for engine thrust (EPR, either left or right or both)
would start INDICATING HIGHER thrust (another words giving false indications),
and even much above max limit.
it is can sometimes be very NASTY to PT2 signal, if Engine Anti Ice was NOT switched ON.
PT2 probe can get filled/BLOCKED with ice dust, now, its signal would change so
that pilots indicators for engine thrust (EPR, either left or right or both)
would start INDICATING HIGHER thrust (another words giving false indications),
and even much above max limit.
As long as were on this, you might also consider that at high altitude there is not much work going on in the front compressor of the engine and as such some accumulation/acretion of ice can take place on probes between the two compressors.
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Seems hard to believe they encountered significant icing at FL330; that's a good 10,000ft above the required icing certification envelope. Unless they'd carried the ice up from a lower altitude?
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Agreed normally little icing potential at ~FL 350, but in a CB (and did they fly through one or not?)? With updrafts strong enough to push through to FL 700 in the tropics, is it not possible for supercooled water droplets to be carried up faster than they can freeze to become "ice powder"? I'm not saying as much as asking, in the meantime I'll go look for that text book....
To be able to reach an altitude where there was insufficient thrust for the weight, suggests that there was a trade off of speed for altitude – speculating, in an attempt to fly over a storm. Alternatively, at a stabilized altitude, the thrust was reduced by selection of engine anti-icing or by the adverse effects of icing. Some engines do suffer from inlet icing near large storms; I encountered debilitating conditions at FL300-350 near the anvil during tests – ‘grauple’, mixed phase icing consisting of soft hail and super cooled water.
In the top of a Cb a severe hail encounter (hard hail) could damage composite structures. Again, I have experienced damage to the nose and wing leading edge fairings such that any longer exposure would have resulted in failure and a rapid drag rise.
A further consideration could be that turbulence caused a loss of speed that approached the stall, but the crew was reluctant to descend to trade altitude for speed increase – reluctance to enter the storm. Any/all of the previous reinforces the message that Cbs should be avoided laterally by a large distance.
The BAC1-11 deep-stall was only notorious during flight testing. The in-service aircraft had stick pushers, and like similar ‘T’ tailed aircraft, it could be stalled, with care, without the push being operative. Deep stall problems are exacerbated when an aircraft experiences high pitch rates due to mishandling or upset gust response in turbulence. CofG (loading) can also affect these characteristics.
There I also the possibility that the translation of ‘loading’ could be associated with increased normal acceleration (g).
In the top of a Cb a severe hail encounter (hard hail) could damage composite structures. Again, I have experienced damage to the nose and wing leading edge fairings such that any longer exposure would have resulted in failure and a rapid drag rise.
A further consideration could be that turbulence caused a loss of speed that approached the stall, but the crew was reluctant to descend to trade altitude for speed increase – reluctance to enter the storm. Any/all of the previous reinforces the message that Cbs should be avoided laterally by a large distance.
The BAC1-11 deep-stall was only notorious during flight testing. The in-service aircraft had stick pushers, and like similar ‘T’ tailed aircraft, it could be stalled, with care, without the push being operative. Deep stall problems are exacerbated when an aircraft experiences high pitch rates due to mishandling or upset gust response in turbulence. CofG (loading) can also affect these characteristics.
There I also the possibility that the translation of ‘loading’ could be associated with increased normal acceleration (g).
