King Air down at Essendon?
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I'v got an hour or two driving the old Beech truck and seeing as every time/off wasn't considering a balanced field length there was no reason to remove ones's hands off the two gas levers (until gear/flap ret) and one always watched the torque guages in yr scan. I'm of the opinion that on this accident old Max (whom I'd known for many years) didn't get a roll back of a donk due gas lever creep. I wish I knew what happened, we all do but will never truly know -(
magine the friction is not set properly before takeoff..
roll down the runway, airborne, hand off lever to raise the gear... and this happens. hardly enough time for the lever to go back?
A common well known example of throttle semi-closure was the Dakota (DC3) which had a throttle friction nut directly beneath the throttle quadrant. Occasionally a throttle or even both could fall back towards idle if the thottle friction nut had not been sufficiently tightened by the PM. That was one reason the PF kept his hand firmly on both throttles during the takeoff run and initial climb. Same reason that the PM kept one hand behind the throttles in case the friction nut didn't do its job because of faulty servicing or more often if some pilot did not write up the defect in the MR after flight.
On rare occasions where the Dakota was flown by only one pilot up front and no one in the RH seat to whom you could delegate operation of flaps and landing gear levers, that was where failing to have the throttle friction nut firmly tightened could cause a problem. As the pilot reached across and down to retract the gear leaving the throttles momentarily unguarded, one or more throttles would close towards idle. A competent pilot would be aware of this probability and delay retracting the landing gear so he could keep one hand firmly on both throttles.
In the case of the Kingair Essendon accident I would have thought it would be extremely doubtful one throttle would "migrate" towards idle without the pilot being aware of it and taking immediate action to restore power.
Back in the 1950's an airman at RAAF Base East Sale got pissed and decided to have a go at flying a Dakota. I think it was night time. He started both engines and taxied to the runway and took off. Witnesses heard the sound of an engine surging after the aircraft lifted off. It was also possible the airman (who had no flying qualifications) failed to uncage the gyro instruments after start up meaning the artificial horizon did not work. That was pure speculation as to why the aircraft crashed shortly after getting airborne. Another theory was when the airman let go of the throttles to retract the landing gear he had forgottem to tighten the throttle friction nut. One or more throttles would have certainly slipped back causing the aircraft to yaw and/or roll and a crash was inevitable.
In the case of the Kingair accident where one theory was a throttle slipping back due to a friction nut defect. if this is a common "problem" with the friction nut design on the Kingair, why was it not written up earlier in the MR as a airworthiness defect.? It might have saved a few lives.. Would not this defect been apparent during scheduled servicing if the servicing had been diligent? Do all Kingairs still have this defect of a dodgy throttle friction nut? . If so, looks like some pilots may have a complacency problem. Isn't that what the much vaunted subject of TEM is all about?
Last edited by Centaurus; 1st Jan 2021 at 11:18.
Do all Kingairs still have this defect of a dodgy throttle friction nut?
Those same aircraft 601 mentioned had the occasional rollback as engineers often released the pressure on the friction nuts during ground runs. If missed in the preflight you soon noticed and made the necessary corrections. Some pilots also had a habit of loosening them after shutdown, don’t know why.
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While I would not totally discount the power lever migration theory, I find it hard to believe experienced pilots would get sucked in by it. Most light aircraft drivers keep one hand on the throttles during takeoff and initial climb, only momentarily removing the hand long enough to retract the gear. The hand goes back on the levers until flap retraction and other non essential activities such as switching off lights. Initiating gear retraction would take 3 seconds at the most - hardly enough time for the power to go right back to negative thrust, and even if it did it would be naturally corrected.
A pilot with an airline background could be in the habit of removing hand from levers at V1, but a pilot with that discipline would probably retract the gear then go back immediately to the power levers if something did not feel right. I don’t think this pilot had any airline training, so would expect he would have kept his hand on the throttles throughout takeoff and rotation.
Either way, I would think it instinctive to push both levers forward if performance was being degraded. Auto feather would take care of a major power loss, but only if the system was armed. If the system was not armed, control with total loss of power close to V1 is very difficult, in fact probably beyond the capability of pilots who have not practiced it in the simulator. We do know that this pilot was not a believer in regular simulator.
The pilot was in a state of panic - that’s really as much as we know. But whether brought on by a medical episode or not is unlikely to ever be discoverable, due to the fireball.
A pilot with an airline background could be in the habit of removing hand from levers at V1, but a pilot with that discipline would probably retract the gear then go back immediately to the power levers if something did not feel right. I don’t think this pilot had any airline training, so would expect he would have kept his hand on the throttles throughout takeoff and rotation.
Either way, I would think it instinctive to push both levers forward if performance was being degraded. Auto feather would take care of a major power loss, but only if the system was armed. If the system was not armed, control with total loss of power close to V1 is very difficult, in fact probably beyond the capability of pilots who have not practiced it in the simulator. We do know that this pilot was not a believer in regular simulator.
The pilot was in a state of panic - that’s really as much as we know. But whether brought on by a medical episode or not is unlikely to ever be discoverable, due to the fireball.
You are correct in that it happens as the hand is moved to the gear lever. It happens in a second and then its the shock factor that gets people. Some, as you surmise, calmly put their hand back on the power levers and correct the situation. Others firmly grip the yoke trying to understand what happens. I have seen it in play I can assure you that it is easily rectified, IF and that's a big IF, you put your right hand back on the power levers.
Groggy
Interesting, grog. What is the cause of the bias toward left PLM over right?
I note that the rudder trim system maintenance manual pages you posted seem to me to show an autopilot servo in the system. However, the ATSB report says:
Am I misreading the maintenance manual pages or are they for a model different to ZCR?
ATSB’s detailed examination of the actuator concludes:
So ATSB discounts the suggestion that the cable broke and was pulled through the actuator due to forces during the crash.
I note that the rudder trim system maintenance manual pages you posted seem to me to show an autopilot servo in the system. However, the ATSB report says:
The [rudder trim] system has no connection to the autopilot/yaw damper or electric trim systems.
ATSB’s detailed examination of the actuator concludes:
Cable damage supports both the left and right cables being under high tension as a result of impact forces. In addition, the lack of any additional abrasion damage to the housing from cable contact indicates that the cable had not spooled through the actuator drum during the accident sequence.
If yaw to the left occurred simultaneous with initiation of gear retraction, it could support the power lever migration theory.
However, the aircraft was veering left from the moment it became airborne and the gear was not selected up. Unless the pilot was in the habit of taking his hand off the power levers at V1 (as some do), this theory is less probable than the mis-set trim cause quoted by the ATSB.
Was the pilot trained to take hand off throttles at V1? Perhaps when he had to go back for re-education after his earlier incident, someone indoctrinated him in this change to usual light twin practice. Some CASA 'experts' may even insist on this - does anyone have any experience of this?
As Capt Ramrod says, there is no need to do that. However, some would have been trained to remove hand at V1, but one would hope that any training in that concept would also have been quite rigorous about use of checklists, including setting throttle friction.
However, the aircraft was veering left from the moment it became airborne and the gear was not selected up. Unless the pilot was in the habit of taking his hand off the power levers at V1 (as some do), this theory is less probable than the mis-set trim cause quoted by the ATSB.
Was the pilot trained to take hand off throttles at V1? Perhaps when he had to go back for re-education after his earlier incident, someone indoctrinated him in this change to usual light twin practice. Some CASA 'experts' may even insist on this - does anyone have any experience of this?
As Capt Ramrod says, there is no need to do that. However, some would have been trained to remove hand at V1, but one would hope that any training in that concept would also have been quite rigorous about use of checklists, including setting throttle friction.
Was the pilot trained to take hand off throttles at V1?
Sure there are performance tables for Part 25 style operations but this particular Kingair was a Part 23 aeroplane.
In Part 23 aeroplanes, I would raise the gear when the remaining runway was insufficient for me to close both throttles and land while looking to achieve and maintain the Blue Line ASAP.. Part 25 gear was called for when a positive climb was established.
I used to have some very long conversations with Examiners asking for V1, V2 etc while conducting my IR renewals in Barons etc.
There is a big difference between "V1" in a Part 25 aeroplane and "Decision Speed" in a part 23 aeroplane.
Last edited by 601; 4th Jan 2021 at 12:55.
601 you are, of course technically correct. I did consider writing ‘Vr’ instead of ‘V1’ but then I thought some smartarse would tell me that the usual practice is to remove hand from throttles at V1.
The problem arises because pilots who have not done simulator but only trained in the aircraft at light weights often think that it is flyable after an engine failure at 94-95 knots, which is the Beech quoted speed, depending on flap. Hence the perception that it is a V1. 95 knots is approximately 5 knots below Vs at gross weight flap zero, so by any measure it can’t be a Vr. And it’s not a Takeoff Safety Speed either. Whoever certified the Beech King Air 200 should have put a big disclaimer at the front of the Flight Manual section on takeoff performance.
Elsewhere on Pprune there has been considerable discussion on this, with certain aces claiming a failure at 95 knots can be taken into the air.
In the hands of a truly expert pilot, current in simulator, it probably can, though 1st & 2nd segment climb can not be achieved without some fudging, ie flying in ground effect for a while.
The problem arises because pilots who have not done simulator but only trained in the aircraft at light weights often think that it is flyable after an engine failure at 94-95 knots, which is the Beech quoted speed, depending on flap. Hence the perception that it is a V1. 95 knots is approximately 5 knots below Vs at gross weight flap zero, so by any measure it can’t be a Vr. And it’s not a Takeoff Safety Speed either. Whoever certified the Beech King Air 200 should have put a big disclaimer at the front of the Flight Manual section on takeoff performance.
Elsewhere on Pprune there has been considerable discussion on this, with certain aces claiming a failure at 95 knots can be taken into the air.
In the hands of a truly expert pilot, current in simulator, it probably can, though 1st & 2nd segment climb can not be achieved without some fudging, ie flying in ground effect for a while.
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Interesting, grog. What is the cause of the bias toward left PLM over right?
I note that the rudder trim system maintenance manual pages you posted seem to me to show an autopilot servo in the system. However, the ATSB report says:Am I misreading the maintenance manual pages or are they for a model different to ZCR?
ATSB’s detailed examination of the actuator concludes:So ATSB discounts the suggestion that the cable broke and was pulled through the actuator due to forces during the crash.
I note that the rudder trim system maintenance manual pages you posted seem to me to show an autopilot servo in the system. However, the ATSB report says:Am I misreading the maintenance manual pages or are they for a model different to ZCR?
ATSB’s detailed examination of the actuator concludes:So ATSB discounts the suggestion that the cable broke and was pulled through the actuator due to forces during the crash.
The Trim system in the B200 is totally manual via cable in all three axis. The servo you see is most likely Yaw damper.
Groggy
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Tom Clements view on Take off data for the B200
Hi,
For those of you talking about the take off data and V speeds this article is well worth reading. Its by Tom Clements a very respected King Air expert in the USA.
Groggy
For those of you talking about the take off data and V speeds this article is well worth reading. Its by Tom Clements a very respected King Air expert in the USA.
Groggy
I can't read that yet, but have done much reading of similar stuff, I am sure.
Flight Safety International was (maybe still is?) the training outfit in the USA that Beech used for initial King Air training. Also I think CASA recognise their training. If you can download from www.pilot18.com an original manual issued by FSI, as wrong as the term may be, on about pages 347 & 348 you will find very clear reference to a 'V1/Vr' of 94 or 95 knots. Hence we have generations of pilots brought up with misconceptions of this aircraft's capabilities. The same manual is reproduced at www.data.tmorris.net
However, in the case of the accident under discussion, the pilot did not rotate until about 111 knots. This would be a nice, manageable number to deal with an engine failure, so maybe he was familiar with its limitations at the lower speeds. Unfortunately, the greater speed would have made it even more difficult to deal with a full left rudder trim application.
Flight Safety International was (maybe still is?) the training outfit in the USA that Beech used for initial King Air training. Also I think CASA recognise their training. If you can download from www.pilot18.com an original manual issued by FSI, as wrong as the term may be, on about pages 347 & 348 you will find very clear reference to a 'V1/Vr' of 94 or 95 knots. Hence we have generations of pilots brought up with misconceptions of this aircraft's capabilities. The same manual is reproduced at www.data.tmorris.net
However, in the case of the accident under discussion, the pilot did not rotate until about 111 knots. This would be a nice, manageable number to deal with an engine failure, so maybe he was familiar with its limitations at the lower speeds. Unfortunately, the greater speed would have made it even more difficult to deal with a full left rudder trim application.
Last edited by Mach E Avelli; 4th Jan 2021 at 23:17.
It’s weird that they plonked an “autopilot servo” in the diagram of a system that does not connect to the auto pilot. Maybe it’s to assist in identifying the physical locations of some of the actual system components?
I’d like to do an experiment on a serviceable aircraft with a properly tensioned rudder trim control cable: Find out how easy would it be for the cable to fall off, and what happens if the cable falls off, one of the pulleys at FS 104 or CSS 437. I’d also like to see how close the cable runs to other moving components.
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However, some would have been trained to remove hand at V1,
When I had the temerity to ask my instructor why did I need to remove my hand of the throttles at V1 I was told it was an airline SOP. "But why?" I asked. I was told it was a psychological thing to prevent the pilot from closing the throttles in fright if an engine failed after lift-off. That was when I realised it was just another OWT. Yet another explanation given to me by an airline check captain was that a one handed rotation (with one hand on the throttles) could cause one wing to lower at VR becuse of the unequal pull on one side of the control wheel as the pilot pulled back on the wheel. I thought he was pulling my leg unil I realised he was serious.
Later I checked the flight crew training manual for the Boeing 737. Nowhere did it recommend the pilot take his hand from the thrust levers at V1 during takeoff. I can only assume that what was once some management pilot's personal opinion has spread around the aviation world like a pandemic and has become yet another of those Old Wives tales that permeate the flying game. In time Old Wives Tales transmogrify into Aviation Lore and bcome God's gospel truth
Sheppey, both reasons you heard for this practice do sound like a load of old bollocks. Back in the day when this became SOP it is unlikely that psychology had found its way into the airline world.
More likely It originated with really heavy unpowered flight controls in large transport aircraft. The flight engineer would set power, then the captain would hold the top of the levers in preparation for a reject if necessary. At V1 the captain would need both hands to haul the heavy beast into the air, but the engineer would still have the throttles. Then the engineer went the way of the dodo, and the surviving dinosaurs retained the practice.
But if it’s SOP, woe betide the pilot who challenges it, or worse, disregards it. Always remember that he who pays the piper calls the tune.
More likely It originated with really heavy unpowered flight controls in large transport aircraft. The flight engineer would set power, then the captain would hold the top of the levers in preparation for a reject if necessary. At V1 the captain would need both hands to haul the heavy beast into the air, but the engineer would still have the throttles. Then the engineer went the way of the dodo, and the surviving dinosaurs retained the practice.
But if it’s SOP, woe betide the pilot who challenges it, or worse, disregards it. Always remember that he who pays the piper calls the tune.
Mach
Perhaps the gear failed to retract?
If the pilot was fumbling, trying to manually move the J-Hook out of the way, and had a power lever migration he would have been in a world of hurt.
If yaw to the left occurred simultaneous with initiation of gear retraction, it could support the power lever migration theory.
However, the aircraft was veering left from the moment it became airborne and the gear was not selected up.
However, the aircraft was veering left from the moment it became airborne and the gear was not selected up.
Perhaps the gear failed to retract?
If the pilot was fumbling, trying to manually move the J-Hook out of the way, and had a power lever migration he would have been in a world of hurt.
I don't discount that power lever migration could have contributed to the accident, simply that the evidence of the trim as reported by the ATSB points to that being the primary cause.
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But if it’s SOP, woe betide the pilot who challenges it, or worse, disregards it. Always remember that he who pays the piper calls the tune.