Asymmetric go-around decision height in light twins
A landing with the gear down and full flaps, even if not on the runway will usually have a better outcome than a stall/spin.
BTW On airline jets, once reverse thrust is selected on touchdown you are committed to the landing. During Ansett's mishap with the B747 landing with the nose gear retracted, the Captain was considering aborting the landing but was prevented from doing so by the F/E as the reverses had deployed.
BTW On airline jets, once reverse thrust is selected on touchdown you are committed to the landing. During Ansett's mishap with the B747 landing with the nose gear retracted, the Captain was considering aborting the landing but was prevented from doing so by the F/E as the reverses had deployed.
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I am with thorn bird !!
If you have completed all checks and alternatives and you end up with the only option but to conduct an approach down to the minima with one engine out - continue with the approach - go below minima and land the bloody thing, there is no real long future in single engine go arounds.
The pilot is already about peaked in the stress level department - adding a go around into the mix may not be a good idea.
In my opinion, there is no option for single engine go arounds.
I was taught in my multi engine training that if you were below 400 ft AGL with one engine inop you WILL land the aircraft. Regardless
If you have completed all checks and alternatives and you end up with the only option but to conduct an approach down to the minima with one engine out - continue with the approach - go below minima and land the bloody thing, there is no real long future in single engine go arounds.
The pilot is already about peaked in the stress level department - adding a go around into the mix may not be a good idea.
In my opinion, there is no option for single engine go arounds.
I was taught in my multi engine training that if you were below 400 ft AGL with one engine inop you WILL land the aircraft. Regardless
Also to consider is we do all our training at light weight - typically one student with an instructor.
Load up some light twins with a commercial payload, and an engine inoperative missed approach is not an option, no matter what altitude.
Load up some light twins with a commercial payload, and an engine inoperative missed approach is not an option, no matter what altitude.
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In fact, in the aircraft used in Qantas cadet pilot training (mostly Aztec) and after a rigorous risk analysis, Qantas went further, and required that, once the gear was down and the flaps out to any setting, even on all engines a landing was required.
oei g/a's are ok with sufficient talent and a bit of height. part of my training were a few go arounds noting the height loss before climbing again.
and its very rare you have to land with full flap.
Last edited by waren9; 4th Dec 2014 at 19:13.
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I don't think it's a good idea in any operation Waren9. To be clear, I'm talking about disallowing a go-around when normally configured, just in case an engine failure might happen at a future point.
No go-arounds allowed with gear & flap extended means that every approach must be a flapless approach until short final - just in case a go around might be needed. This either requires exclusively flapless landings, or a requirement to configure flap on short final. And all for the remote possibility of an event requiring a simultaneous go-around and engine failure.
There is no support for this concept in any POH or AFM I've read.
CAO 20.7.1 does not require me to guarantee performance in this eventuality - an engine failure coincident with a go-around - even in my RPT turboprop.
Let's get back to the discussion of go-around decision making with an engine already failed & secured.
No go-arounds allowed with gear & flap extended means that every approach must be a flapless approach until short final - just in case a go around might be needed. This either requires exclusively flapless landings, or a requirement to configure flap on short final. And all for the remote possibility of an event requiring a simultaneous go-around and engine failure.
There is no support for this concept in any POH or AFM I've read.
CAO 20.7.1 does not require me to guarantee performance in this eventuality - an engine failure coincident with a go-around - even in my RPT turboprop.
Let's get back to the discussion of go-around decision making with an engine already failed & secured.
The decision making process needs to consider so many variables:
1 Aircraft type and loading - e.g. Baron versus Apache versus Chieftain/C402 etc. A 285 hp Baron with four on board is not too bad a performer, and in the right hands could probably execute a single engine missed approach from the ILS minima. But see 3. below for the caveat. A 150 hp Apache is committed to a landing at the time the engine fails, no matter what skill level you have. Certain laws of physics can not be denied. 150 h.p. in a draggy airframe such as an Apache can only propel it forwards and downwards - albeit fairly slowly. A Chieftain or C402 with every seat occupied probably lies somewhere between these two.
2 Temperature. Under extreme summer conditions turbocharged twins will suffer overheating if the remaining engine is flogged at the low speeds required to avoid obstacles when climbing. Normally aspirated engines won't be developing rated horsepower on a hot day. Plus of course density altitude affects all aircraft.
3 Pilot familiarity with the type and overall proficiency. A five hour endorsement won't prepare most pilots adequately for such a critical event as a OEI missed approach from the minima in a fully loaded twin. And now that formal endorsements are not required on each type, pilot familiarity and overall proficiency will be even more pertinent to such decision making. How the Examiner will adequately assess this on a flight test will be interesting to watch - safely from the ground, thank you.
Re the reference to the VH CLY accident. If that was the Heron, it was not caused by an engine-inoperative lack of performance. An engine out in a Heron is almost a non event. In fact we could and did take off on three engines sometimes, though not with passengers. The cause of that prang was as in 3 above. If you dump the flaps from the landing setting back to the takeoff setting on a Heron, in a split second they go from about 60 degrees to about 20 degrees - with predictable consequences.
1 Aircraft type and loading - e.g. Baron versus Apache versus Chieftain/C402 etc. A 285 hp Baron with four on board is not too bad a performer, and in the right hands could probably execute a single engine missed approach from the ILS minima. But see 3. below for the caveat. A 150 hp Apache is committed to a landing at the time the engine fails, no matter what skill level you have. Certain laws of physics can not be denied. 150 h.p. in a draggy airframe such as an Apache can only propel it forwards and downwards - albeit fairly slowly. A Chieftain or C402 with every seat occupied probably lies somewhere between these two.
2 Temperature. Under extreme summer conditions turbocharged twins will suffer overheating if the remaining engine is flogged at the low speeds required to avoid obstacles when climbing. Normally aspirated engines won't be developing rated horsepower on a hot day. Plus of course density altitude affects all aircraft.
3 Pilot familiarity with the type and overall proficiency. A five hour endorsement won't prepare most pilots adequately for such a critical event as a OEI missed approach from the minima in a fully loaded twin. And now that formal endorsements are not required on each type, pilot familiarity and overall proficiency will be even more pertinent to such decision making. How the Examiner will adequately assess this on a flight test will be interesting to watch - safely from the ground, thank you.
Re the reference to the VH CLY accident. If that was the Heron, it was not caused by an engine-inoperative lack of performance. An engine out in a Heron is almost a non event. In fact we could and did take off on three engines sometimes, though not with passengers. The cause of that prang was as in 3 above. If you dump the flaps from the landing setting back to the takeoff setting on a Heron, in a split second they go from about 60 degrees to about 20 degrees - with predictable consequences.
Last edited by Mach E Avelli; 5th Dec 2014 at 00:36.
In the past, PPRuNe has seen numerous discussions on pilot technique to be used if a wing should drop at the point of stall. The expression "pick up the wing with rudder" is frequently used in this context and there is little doubt many instructors teach students to skid the wings level before applying aileron. This is of course faulty technique and has the potential to cause an incipient spin in the direction to the dropped wing. Nevertheless the technique is almost universally taught at flying schools.
I agree with Mach E Avelli, I'd never dump flaps. Having had 4 engine failures, 2 of which have been on take off, it is a recipe for disaster.
My first twin was a L12A and the last thing you would want to do is dump the Fowler flaps.
Every endorsement I've ever done has been identify, feather, gear up and control. But most of all CONTROL.
Better to have a prang at the end of the runway with wings level than cartwheeling because you let the wing drop.
As for decision height, I can testify. ALL non transport category twins have a decision height of around 400 feet.
Picture this scenario, Pa39, 8inches of left prop broken, engine feathered but canted 10 degrees off centre, night landing. This is what I faced in 1984, flew the aircraft 10 knots above approach speed and made the decision height 500 feet. Result here to tell the tale.
If I was to repeat my career And needed to do an initial twin, I'd seek out an older instructor with experience. People such as Bill Whitworth at Bankstown or his equivalent in Moorabbin or Archerfield would be money well spent
My first twin was a L12A and the last thing you would want to do is dump the Fowler flaps.
Every endorsement I've ever done has been identify, feather, gear up and control. But most of all CONTROL.
Better to have a prang at the end of the runway with wings level than cartwheeling because you let the wing drop.
As for decision height, I can testify. ALL non transport category twins have a decision height of around 400 feet.
Picture this scenario, Pa39, 8inches of left prop broken, engine feathered but canted 10 degrees off centre, night landing. This is what I faced in 1984, flew the aircraft 10 knots above approach speed and made the decision height 500 feet. Result here to tell the tale.
If I was to repeat my career And needed to do an initial twin, I'd seek out an older instructor with experience. People such as Bill Whitworth at Bankstown or his equivalent in Moorabbin or Archerfield would be money well spent
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Aztec, I think. Reason #671 to scrap it and buy something younger than the chief pilot.
Most non transport category twins have no decision height specified - see post #15 above by JT in particular. (But I agree with everything else you said!)
ALL non transport category twins have a decision height of around 400 feet.
universally taught at flying schools. Pig's Arse. Not at my school. If this practice is so prevalent, why aren't CFI's and FE's picking it up in S&P's or renewals? Please remember a vocal minority of ill advised PPRuNe contributors are not the practical majority
Definitely qualifies for a seat in the Senate.
might be fair enough in a training environment but would be very restrictive in a commercial operation.
As I understand your comment, asymmetric approaches must be a common situation in "commercial operations", and, therefor, a higher risk ( less safe) operation is justified on the basis of a commercial operation.
I trust you are only a FlightSim pilot, it is an absolute nono to make decisions based on commercial considerations in a non-normal situation. Strangely enough, "the law" suggests precisely this.
The FAA figures are sobering, there is a greater probability of a fatal crash in the case of an engine failure in a light twin than in a single.
I suggest you
Pig's Arse. Not at my school.
A rather public announcement of your non-compliance with the Part 61 MOS, Competency Standards for a stall recovery.
Seriously, this MOS will kill people.
Tootle pip!!
Last edited by LeadSled; 6th Dec 2014 at 00:38.
When you live....
Can anyone remember a light twin with only one hydraulic pump ? If the engine failed on that side you needed to hand pump the gear and flaps, not ideal during a go around.
Now fitted with an AUX backup
Early model Piper Aztecs only had one hydraulic pump as standard, the later F models all came with two pumps factory fitted.
When I did my Navajoo endorsement, the checkie doing it was also endorsing another company pilot Captain Ace Four Bars Baron expert.
Captain Ace Four Bars had a number of asymmetric go arounds because he would persist in leaving the gear up until late on the base leg, consequently final the gear would not be locked down and around we would go!
When I did my Navajoo endorsement, the checkie doing it was also endorsing another company pilot Captain Ace Four Bars Baron expert.
Captain Ace Four Bars had a number of asymmetric go arounds because he would persist in leaving the gear up until late on the base leg, consequently final the gear would not be locked down and around we would go!
Folks,
I would suggest that what you are doing, in risk management terms, on every IMC approach on a light twin (unless certified to the "commuter" amendment to FAR 23) are betting on an engine not failing --- and statistically it is a pretty good bet, except in the case of fuel starvation, a common cause of "engine failure".
It is a nonsense to suggest that you have to stay clean until short final --- predicated on a simultaneous engine failure and a missed approach.
Flying an unstable approach is a greater risk (less safe if you insist on the use of the "safe" word) probability of causing an accident and accident, than a probability of an engine failure and a missed approach on the same approach.
For the same reason, the teaching of maintaining the "blue line" speed to short final is seriously flawed teaching, but very common, and apparently "encouraged" by CASA.
It is a very conspicuous example of the very poor risk management approach all too common in Australian aviation, that the "maintain blue line speed" demands that a final approach is unstable, ie: that 1:1 normal approaches are of increased risk, to cover an approximately 1: 10-4 risk.
As to the various claims of heroic pilots, and extraordinarily able pilots who have all sorts of examples of "what they did" --- what they mean is "this is the situation I found myself in, and didn't die, so what I did must be OK for all operations.
Tootle pip!!
I would suggest that what you are doing, in risk management terms, on every IMC approach on a light twin (unless certified to the "commuter" amendment to FAR 23) are betting on an engine not failing --- and statistically it is a pretty good bet, except in the case of fuel starvation, a common cause of "engine failure".
It is a nonsense to suggest that you have to stay clean until short final --- predicated on a simultaneous engine failure and a missed approach.
Flying an unstable approach is a greater risk (less safe if you insist on the use of the "safe" word) probability of causing an accident and accident, than a probability of an engine failure and a missed approach on the same approach.
For the same reason, the teaching of maintaining the "blue line" speed to short final is seriously flawed teaching, but very common, and apparently "encouraged" by CASA.
It is a very conspicuous example of the very poor risk management approach all too common in Australian aviation, that the "maintain blue line speed" demands that a final approach is unstable, ie: that 1:1 normal approaches are of increased risk, to cover an approximately 1: 10-4 risk.
As to the various claims of heroic pilots, and extraordinarily able pilots who have all sorts of examples of "what they did" --- what they mean is "this is the situation I found myself in, and didn't die, so what I did must be OK for all operations.
Tootle pip!!
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Leadsled - yes!
Every ops-normal approach should be flown the same way, using speeds & configuration recommended for the type. There is nothing wrong with a go-around from the flare or even later, should it be necessary. You'll be well below Vyse of course, which is irrelevant to an AEO go around.
If an approach is commenced when already OEI - then a decision height is useful for VFR, an adjusted MDA is often necessary for IFR, and you might not configure quite so early on the approach (especially in IMC.)
If you lose an engine on approach or during a go around, you get to earn your pay that day. It's possible that 100% power on the live engine might briefly be needed even to continue the approach! But most pilots don't conduct every ops-normal approach based on the very low risk of that circumstance, nor does CASA require it at any level of the industry.
When did this become controversial?
Every ops-normal approach should be flown the same way, using speeds & configuration recommended for the type. There is nothing wrong with a go-around from the flare or even later, should it be necessary. You'll be well below Vyse of course, which is irrelevant to an AEO go around.
If an approach is commenced when already OEI - then a decision height is useful for VFR, an adjusted MDA is often necessary for IFR, and you might not configure quite so early on the approach (especially in IMC.)
If you lose an engine on approach or during a go around, you get to earn your pay that day. It's possible that 100% power on the live engine might briefly be needed even to continue the approach! But most pilots don't conduct every ops-normal approach based on the very low risk of that circumstance, nor does CASA require it at any level of the industry.
When did this become controversial?