Air North Brasilia Crash in Darwin (Merged)
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Relax 737 has said...
"There's an old saying...
When you're up to your ar$e in alligators, it's difficult to remember you were there to drain the swamp.
The analogy applies so much in aviation, and when everything is going pear shaped, professional aviators aren't much different from the guy draining the swamp. What we do have going for us is instinctive action based on ingrained training, but if you put a foot wrong then it's curtains."
Been in the business for 40 years Mate! Wanna tell me what the hell you're talkin' about?
"There's an old saying...
When you're up to your ar$e in alligators, it's difficult to remember you were there to drain the swamp.
The analogy applies so much in aviation, and when everything is going pear shaped, professional aviators aren't much different from the guy draining the swamp. What we do have going for us is instinctive action based on ingrained training, but if you put a foot wrong then it's curtains."
Been in the business for 40 years Mate! Wanna tell me what the hell you're talkin' about?
archangel7...
Why? And what evidence have you got to conclude that it was a '...high-speed crash'?
What obie2 said:
I don't pretend to know what happened here, and I'll bet at this point of time the ATSB folks don't know (exactly) either. But (and despite the fact that I haven't had the advantage of a 6-week accident investigation training course) like obie2, I think I've been around long enough to understand a few things that DIDN'T happen in this accident.
But a high-speed crash on take-off points the finger more towards a mechanical error then human error.
And what evidence have you got to conclude that it was a '...high-speed crash'? What obie2 said:
Been in the business for 40 years Mate! Wanna tell me what the hell you're talkin' about?
Last edited by SIUYA; 25th Mar 2010 at 10:37. Reason: Let's get some perspective here, for Chrissakes!
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I don't pretend to know what happened here, and I'll bet at this point of time the ATSB folks don't know (exactly) either.
From wiki:
Embraer 120 Accident history
The aircraft does have some history of mechanical failure (although, not an unusual amount for 200+ airframes over 25 years of service), however the publicly released circumstances of this accident are still suggestive of a training related problem until the CVR/FDR can be read.
Embraer 120 Accident history
- Atlantic Southeast Airlines Flight 2311, crashed in Brunswick, Georgia on April 5, 1991. The crash claimed the lives of all twenty-three people on board, including former U.S. Senator John Tower of Texas and astronaut Sonny Carter. This was due to propeller control failure.
- Continental Express Flight 2574, broke up in flight on September 11, 1991, killing all of the passengers and crew members. The media stated that initially people speculated that a bomb had destroyed the aircraft; the NTSB discovered that missing screws on the horizontal stabilizer led to the crash.
- Atlantic Southeast Airlines Flight 529, crashed in a field near Carrollton, Georgia on August 21, 1995. Of the twenty-nine people on board, ten were killed. This was due to failure of a propeller blade and subsequent severe engine vibration and failure.
- Comair Flight 3272 crashed in Michigan on January 9, 1997. All of the passengers and crew died, the probable cause was in-flight icing.
- Airnorth VH-ANB took off approximately 10.10am (ACST) on March 22, 2010, from Darwin International Airport on a routine training flight when it apparently banked sharply to the left and crashed into the nearby bushland at RAAF Base Darwin.
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ace from space, interesting post. You said:
This is alarming. You were on the verge of being out of control. It could be said that you *were* out of control - given your continued problem with directional control.
Is this a frequent occurrence on these sorts of training flights? Is CASA aware of this?
Being on the verge of losing control, just a small hiccup (e.g. wind gust) would have put you out of control.
With the rapidly developing yaw and roll towards the dead engine, what then is the procedure? Is there an officially documented one?
You said that you "decreased power on the good engine". Is it possible that somebody could instead try to increase power on the "failed" engine - with a long spool-up time then making a crash inevitable?
In over 6000 hours on type, twice I experienced a situation when the #1 engine was simulated to fail (by setting flight idle) after V1 and the speed is allowed to get a little slow, the a/c required not only full opposite rudder but also full opposite aileron to check the yaw and roll to the left. (and even then the a/c continued to deviate from centreline)
The situation was remedied by reducing the power on the live engine to reduce the asymmetric yaw.
The situation was remedied by reducing the power on the live engine to reduce the asymmetric yaw.
Is this a frequent occurrence on these sorts of training flights? Is CASA aware of this?
Being on the verge of losing control, just a small hiccup (e.g. wind gust) would have put you out of control.
With the rapidly developing yaw and roll towards the dead engine, what then is the procedure? Is there an officially documented one?
You said that you "decreased power on the good engine". Is it possible that somebody could instead try to increase power on the "failed" engine - with a long spool-up time then making a crash inevitable?
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On windmilling again. Apologies to all if this subthread is getting tiresome.
AerocatS2A, thank you for the dramatic and interesting post. Hugh Jarse, thank you too for the further clarification. t303, thank you for the detailed account of an EMB-120 simulated EFATO.
I am still incredulous that any twin can climb with one prop windmilling.
AerocatS2A and Hugh, I concede that you have given credible accounts of this occurence in the DHC8 simulator.
But, 400 RPM (stated by AerocatS2A) for a windmilling prop sounds a little too low. This value leads me to suspect that there is some form of lock in the propeller - to prevent the fine pitch angles that give the high windmilling RPM and consequent enormous drag.
Is there such a lock? Does it operate at all times the aircraft is airborne? Is takeoff permitted with it unserviceable?
If there is such a lock, then we have different ideas of what "windmilling" means.
t303, your account refers to simulating the engine failure by setting flight-idle. Flight-idle is not the same as windmilling. This is twice now that I have called you on this.
ace from space also said flight-idle for the engine failure simulation on the EMB-120. His was an interesting account and revealed that the aircraft was virtually out of control. How would it have gone if the prop was windmilling?
AerocatS2A, thank you for the dramatic and interesting post. Hugh Jarse, thank you too for the further clarification. t303, thank you for the detailed account of an EMB-120 simulated EFATO.
I am still incredulous that any twin can climb with one prop windmilling.
AerocatS2A and Hugh, I concede that you have given credible accounts of this occurence in the DHC8 simulator.
But, 400 RPM (stated by AerocatS2A) for a windmilling prop sounds a little too low. This value leads me to suspect that there is some form of lock in the propeller - to prevent the fine pitch angles that give the high windmilling RPM and consequent enormous drag.
Is there such a lock? Does it operate at all times the aircraft is airborne? Is takeoff permitted with it unserviceable?
If there is such a lock, then we have different ideas of what "windmilling" means.
t303, your account refers to simulating the engine failure by setting flight-idle. Flight-idle is not the same as windmilling. This is twice now that I have called you on this.
ace from space also said flight-idle for the engine failure simulation on the EMB-120. His was an interesting account and revealed that the aircraft was virtually out of control. How would it have gone if the prop was windmilling?
One important factor with regard to a windmilling prop is the powertrain configuration, the PW100 series are free turbines so a windmilling prop will, in effect, only be driving the power turbine, hence the general lack of NTS systems on these powerplants.
Compared to a Garrett (for example) where the prop will have the job of driving the turbine and compressor assembly and the windmilling drag will be very significant.
I don't know how FI drag compares to actual failed engine/windmilling prop drag but the platform I fly also performs with one engine at FI, obviously not as well as when feathered or with zero thrust set but a very definite positive gradient nonetheless.
I think I agree with FGD though, I don't think FI would replicate a completely failed powerplant with a pitchlocked prop. One aircraft I have flown (in a sim) without autofeathering could only climb briefly before starting a gradual descent.
Compared to a Garrett (for example) where the prop will have the job of driving the turbine and compressor assembly and the windmilling drag will be very significant.
I don't know how FI drag compares to actual failed engine/windmilling prop drag but the platform I fly also performs with one engine at FI, obviously not as well as when feathered or with zero thrust set but a very definite positive gradient nonetheless.
I think I agree with FGD though, I don't think FI would replicate a completely failed powerplant with a pitchlocked prop. One aircraft I have flown (in a sim) without autofeathering could only climb briefly before starting a gradual descent.
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But, 400 RPM (stated by AerocatS2A) for a windmilling prop sounds a little too low. This value leads me to suspect that there is some form of lock in the propeller - to prevent the fine pitch angles that give the high windmilling RPM and consequent enormous drag.
This is something you should know instinctively.
When a prop is feathered, it just about always still rotates a little inflight, every configuration is different.
No multi engine aircraft that I know of when the powerplant fails, the prop will move to the fine position ?.
ace from space also said flight-idle for the engine failure simulation on the EMB-120. His was an interesting account and revealed that the aircraft was virtually out of control. How would it have gone if the prop was windmilling?
I have never experienced a prop ceased in fine pitch, but FI on either type presents a huge amount of drag, I believe the engine is not driving the propeller in either case, so what is ?.
All the turbine aircraft I have flown will still climb with one engine at FI and the other producing max power above V1 on T/O and inflight.
400 RPM is not rotating slowly and it does sound a little slow for the coarse pitch stops (min governed position), which is where a windmilling prop will settle to.
However at least one type of turboprop has an autofeather system which actually lets the prop cycle and this allows less drag than the feathered prop.
Any pitch lock system would be worse as it would lock the prop most likely in a finer than ideal position.
Unless you have shut down the gas generator then it will still be producing some thrust however small.
However at least one type of turboprop has an autofeather system which actually lets the prop cycle and this allows less drag than the feathered prop.
Any pitch lock system would be worse as it would lock the prop most likely in a finer than ideal position.
I have never experienced a prop ceased in fine pitch, but FI on either type presents a huge amount of drag, I believe the engine is not driving the propeller in either case, so what is ?.
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obie, I'm more than happy to explain, but not sure whether you want the analogy explained or the bit after, so I'll do both.
An analogy is a similarity or parallelism.
The guy being up to his butt in alligators tends to forget why he's there because he panics.
Pilots aren't dissimilar; believe it or not, we do panic from time to time, and let me assure you, when I had an explosive decompression at FL390, I did experience a moment of panic. That panic was probably associated, in a small way, with the sensation that my guts was going to end up on the floor, and it wasn't going to be through my mouth!
However, what pilots have going for them is bags of (hopefully good) training, so after that instant of panic, the training kicks in and they do what is necessary, but in a critical situation if not performed accurately, it can be over in an instant.
There you are, the old analogy about the alligators, which, incidentally, is as old as aviation itself (may have been coined by Wilbur or Orville) explained. I'm surprised you haven't come across it previously.
I first saw it whilst at Air North where a wag put one of those up on the whiteboard every morning.
Another was
Working here is like being a pubic hair on a toilet seat; sooner or later you'll get pissed off.
Now I'm not going to explain that one to you!
This has evolved into a good thread, way off topic at times, but I bet there are people learning a lot from this about turbo props and their operation.
An analogy is a similarity or parallelism.
The guy being up to his butt in alligators tends to forget why he's there because he panics.
Pilots aren't dissimilar; believe it or not, we do panic from time to time, and let me assure you, when I had an explosive decompression at FL390, I did experience a moment of panic. That panic was probably associated, in a small way, with the sensation that my guts was going to end up on the floor, and it wasn't going to be through my mouth!
However, what pilots have going for them is bags of (hopefully good) training, so after that instant of panic, the training kicks in and they do what is necessary, but in a critical situation if not performed accurately, it can be over in an instant.
There you are, the old analogy about the alligators, which, incidentally, is as old as aviation itself (may have been coined by Wilbur or Orville) explained. I'm surprised you haven't come across it previously.
I first saw it whilst at Air North where a wag put one of those up on the whiteboard every morning.
Another was
Working here is like being a pubic hair on a toilet seat; sooner or later you'll get pissed off.
Now I'm not going to explain that one to you!
This has evolved into a good thread, way off topic at times, but I bet there are people learning a lot from this about turbo props and their operation.
Last edited by relax737; 26th Mar 2010 at 00:02.
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43 inch,
Sure, whilst ever the hot section is producing hot air, it could be argued that in some respect the engine has the ability to produce a small amount of power, what does the TQ gauge tell you ?.
If the aircraft was stationary on the ground with the engine operating at FI, what power is the engine producing, in terms of TQ ?, so does it make the amount produced relevant, I do not think so, great to have but probably not even indicating on the TQ gauge.
So, unless the propeller is ceased in fine pitch, how does one have this massive amount of "windmilling" drag if the engine has actually failed and the prop will start feathering on its own ?.
What I think many here are thinking about is the FI position, engine still producing high oil pressure, prop lever still selecting high rpm and the oil making the fine pitch happen, yet engine not actually scheduling enough fuel to produce positive TQ, this produces high drag (common training scenario, we've all seen it, but would it happen in real life ?).
A ceased prop in fine'ish pitch will produce high drag.
For example, jump into a CSU single engine piston, climb to 10,000ft, pull the mixture, set the glide, once estabilshed write down the FPM, pull the pitch lever into the coarse position ( pull pitch lever out ), check the FPM.
I did this in a lightly loaded C207, first reading was 1480FPM, the second was 690FPM. Whilst the single engine prop operates differently this indicates what a small pitch change will do to a glide/drag produced.
Sure, whilst ever the hot section is producing hot air, it could be argued that in some respect the engine has the ability to produce a small amount of power, what does the TQ gauge tell you ?.
If the aircraft was stationary on the ground with the engine operating at FI, what power is the engine producing, in terms of TQ ?, so does it make the amount produced relevant, I do not think so, great to have but probably not even indicating on the TQ gauge.
So, unless the propeller is ceased in fine pitch, how does one have this massive amount of "windmilling" drag if the engine has actually failed and the prop will start feathering on its own ?.
What I think many here are thinking about is the FI position, engine still producing high oil pressure, prop lever still selecting high rpm and the oil making the fine pitch happen, yet engine not actually scheduling enough fuel to produce positive TQ, this produces high drag (common training scenario, we've all seen it, but would it happen in real life ?).
A ceased prop in fine'ish pitch will produce high drag.
For example, jump into a CSU single engine piston, climb to 10,000ft, pull the mixture, set the glide, once estabilshed write down the FPM, pull the pitch lever into the coarse position ( pull pitch lever out ), check the FPM.
I did this in a lightly loaded C207, first reading was 1480FPM, the second was 690FPM. Whilst the single engine prop operates differently this indicates what a small pitch change will do to a glide/drag produced.
Most turboprops whilst on the ground with FI selected are off and running, certainly way too much thrust for a controllable taxi, also consider landing when idle is not trimmed as low as it should be, easy to float clear over the horizon.
They generate significant thrust at idle although the prop is generally on the fine stop i.e. ungoverned, I wouldn't think (but don't know) at Vmca type speeds that there would be as significant a windmillling effect although we are cautioned on most types I've operated to use zero thrust settings and not FI.
The prop in question is likely to be a double acting mechanism (again I don't know for sure) meaning it is feathered by an autofeather system (inoperative if a power lever is retarded) and in the case of loss of oil pressure the hub will lock the propeller blades at the existing angle until, either piston oil pressure is restored or the auxiliary feather pump is operated (manual fx or condition lever)
So a windmilling propeller is a real possibility in these scenarios, and it is on the drivers to recognise and feather where required (as soon as positive control and rate of climb are established).
They generate significant thrust at idle although the prop is generally on the fine stop i.e. ungoverned, I wouldn't think (but don't know) at Vmca type speeds that there would be as significant a windmillling effect although we are cautioned on most types I've operated to use zero thrust settings and not FI.
The prop in question is likely to be a double acting mechanism (again I don't know for sure) meaning it is feathered by an autofeather system (inoperative if a power lever is retarded) and in the case of loss of oil pressure the hub will lock the propeller blades at the existing angle until, either piston oil pressure is restored or the auxiliary feather pump is operated (manual fx or condition lever)
So a windmilling propeller is a real possibility in these scenarios, and it is on the drivers to recognise and feather where required (as soon as positive control and rate of climb are established).
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A lot of speculation on the operation of the Brasilia prop.
A few pages of the simplified operation can be found at Smart Cockpit. This is dumbed down for pilots so may not tell the whole story, - but I suspect there may be a little more to it than some here appreciate.
SmartCockpit - Airline training guides, Aviation, Operations, Safety
A few pages of the simplified operation can be found at Smart Cockpit. This is dumbed down for pilots so may not tell the whole story, - but I suspect there may be a little more to it than some here appreciate.
SmartCockpit - Airline training guides, Aviation, Operations, Safety
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Well, after reading all these posts over the last hour, I just want to say a thanks to Frigatebird 
....well balanced, good simulator example we can all learn from and a sensible approach to this tragic incident "anything is possible..."
It just makes you stop and think...
Stay safe one and all....
Stiky
....well balanced, good simulator example we can all learn from and a sensible approach to this tragic incident "anything is possible..." It just makes you stop and think...
Stay safe one and all....
Stiky
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Fred,
Just about all of this discussion is regarding FGD statement that any aircraft with a windmilling prop will not climb, something he/she claims we should know instinctively, or words to that effect.
Many have disputed this from their own hands on experience, yet some continue this "windmilling prop / no climb theory".
To be polite, it was a theory that was put to peer review on this thread and has since been denied as true by many.
I would not agree with that statement.
So do you have to pull beta to get the aircraft on the ground ?.
Disclaimer: I have never flown a braz, am not referring to the ANB accident, this is a purely academic discussion, as I do not agree with FGD's earlier statement.
Baron Beeza, that is a good link,thanks.
Just about all of this discussion is regarding FGD statement that any aircraft with a windmilling prop will not climb, something he/she claims we should know instinctively, or words to that effect.
Many have disputed this from their own hands on experience, yet some continue this "windmilling prop / no climb theory".
To be polite, it was a theory that was put to peer review on this thread and has since been denied as true by many.
Most turboprops whilst on the ground with FI selected are off and running
So do you have to pull beta to get the aircraft on the ground ?.
Disclaimer: I have never flown a braz, am not referring to the ANB accident, this is a purely academic discussion, as I do not agree with FGD's earlier statement.
Baron Beeza, that is a good link,thanks.
Last edited by Josh Cox; 26th Mar 2010 at 02:15. Reason: spelling
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In my type we brief to climb to acceleration altitude (400 feet AGL) with a windmilling prop (NTSing), T/O flap and gear retracted.
The only time we will feather the engine straight away is if we have an NTS failure in which it will happen as soon as the gear has been selected up.
A turbine engined aeroplane above 5700kg is certified to achieve a positive rate until the gear has been selected up, then must achieve a certain climb gradient until the end of the second segment, which in my case is 2%. This is with a windmilling prop, gear selected up and take off flap extended.
We do this all the time in the sim, and on our base checks and it performs well. In the sim at max weight it also performs above the minimum required climb gradient provided you maintain V2 with correct technique.
The only time we will feather the engine straight away is if we have an NTS failure in which it will happen as soon as the gear has been selected up.
A turbine engined aeroplane above 5700kg is certified to achieve a positive rate until the gear has been selected up, then must achieve a certain climb gradient until the end of the second segment, which in my case is 2%. This is with a windmilling prop, gear selected up and take off flap extended.
We do this all the time in the sim, and on our base checks and it performs well. In the sim at max weight it also performs above the minimum required climb gradient provided you maintain V2 with correct technique.
Remember this was on a 21 year old airframe and a/c performance usually diminishes with age. Darwin is also a failry hot climate - certainly not standard field performance.
There are many school of thoughts that it's ok to fail an engine before V1 OR wait until 400 feet and give yourself some safety margin.
This was an accident, no matter how you look at it. I can potentially see CASA regs being ammended re this type of training - either to mandate sim training and/or limiting simulated EFATO to a min altitude.
There's no reason the a/c cant be configured to simulate an EFATO at 2000 feet
There are many school of thoughts that it's ok to fail an engine before V1 OR wait until 400 feet and give yourself some safety margin.
This was an accident, no matter how you look at it. I can potentially see CASA regs being ammended re this type of training - either to mandate sim training and/or limiting simulated EFATO to a min altitude.
There's no reason the a/c cant be configured to simulate an EFATO at 2000 feet
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Most turboprops whilst on the ground with FI selected are off and running
So do you have to pull beta to get the aircraft on the ground ?
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I've found with aircraft with 4 blades or more you usually have to land with the power on and quite a bit of power. If you pulled the power back to FI you will fall out of the sky as those big blades start to disc. I've found when training with guys on one of these types you have to be careful they don't pull the power off too soon or it can quickly get away from you. With aircraft with 3 blades such as Cheyennes and older B200's you can get away with pulling the power back to idle at around 30' and flying them on.
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Thanks Harry,
On landing, I have never needed to use beta, i.e. a clear demonstration to me of how little power, if any is being produced at FI, with the power lever/s at the gate.
Which I believe ties in with my opinion that with one engine at FI and the other at max pwr, inflight, is pretty much the worst drag situation you can find yourself in, excluding a ceased prop, which I've not experienced or seen.
It would appear from Baron Beeza's link that, the braz for example will pitch lock at a lower pitch than it was at when a EFATO occurs, IMHO theoritically a better scenario than FI with power lever at the gate.
I have not flown a turbine twin that will not climb on one engine with the other at flight idle and power lever at the gate, so to me this further disproves FGD's earlier statement.
Plus the braz pilots I've met are of the opinion that the braz, for example, with correct technique will easily fly away with 2 pob on one engine, with the other engine at FI.
Whilst failing engines inflight can be a dangerous procedure, it can be done relatively safely, but it is certainly not wish out risk, smoking hole in the end of the runway type of risk, have never heard of someone losing their life in a sim.
On landing, I have never needed to use beta, i.e. a clear demonstration to me of how little power, if any is being produced at FI, with the power lever/s at the gate.
Which I believe ties in with my opinion that with one engine at FI and the other at max pwr, inflight, is pretty much the worst drag situation you can find yourself in, excluding a ceased prop, which I've not experienced or seen.
It would appear from Baron Beeza's link that, the braz for example will pitch lock at a lower pitch than it was at when a EFATO occurs, IMHO theoritically a better scenario than FI with power lever at the gate.
I have not flown a turbine twin that will not climb on one engine with the other at flight idle and power lever at the gate, so to me this further disproves FGD's earlier statement.
Plus the braz pilots I've met are of the opinion that the braz, for example, with correct technique will easily fly away with 2 pob on one engine, with the other engine at FI.
Whilst failing engines inflight can be a dangerous procedure, it can be done relatively safely, but it is certainly not wish out risk, smoking hole in the end of the runway type of risk, have never heard of someone losing their life in a sim.
Last edited by Josh Cox; 26th Mar 2010 at 04:09. Reason: spelling