Engine Failure in Cruise - Inflight Decision Making
Building on the original post and taking it back to departure
Lets say he/she departed somewhere with CB like features ( elevation / terrain )
He/she knows the cloud base is 100ft above the minima (atis)
The aircraft is a typical piston with a MTOW sea level max climb OEI of between 250 / 380fpm
What do schools teach these days on pre departure planning or is it just brushed over with the instruction of " make allowances "
- and so the tread continues where he/she reaches cruise and then the engine fails -
My edit - minor grammar
Lets say he/she departed somewhere with CB like features ( elevation / terrain )
He/she knows the cloud base is 100ft above the minima (atis)
The aircraft is a typical piston with a MTOW sea level max climb OEI of between 250 / 380fpm
What do schools teach these days on pre departure planning or is it just brushed over with the instruction of " make allowances "
- and so the tread continues where he/she reaches cruise and then the engine fails -
My edit - minor grammar
Last edited by megle2; 20th Dec 2012 at 20:29.
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Building on the original post and taking it back to departure
Lets say
he/she departed somewhere with CB like features ( elevation / terrain )
He/she knows the cloud base is 100ft above the minima (atis)
The
aircraft is a typical piston with a MTOW sea level max climb OEI of between 250
/ 380fpm
2/ you've described departure out of Canberra yet qouted figures for OEI climb at mean sea-level.
It's this lack of understanding - a clear inablity to look at 'the big picture' - which is why people like the OP need to ask in the first place and why people like yourself seem determined to give the wrong advice or confuse the issue.
For the record. Revising the minima for the OEI best ROC was standard teaching as part of my instrument rating training. A quick bit of maths that I am sure many have forgotten. I find it hard to beleive that other schools wouldn't teach this.
In any case. The answer is B
Stacko did you fall outa bed this morning
1 I didn't specify a type, just a general statement of where they all fall, I think the Baron 58 by memory was one of the better ones at about 380fpm / sea level
2 Yes of course, most of the schools are at sea level, so thats what they talk about, I was wondering what the speel is for when they depart elsewhere
You may have had " revising the minima " at your school so put down the process they taught you to come up with an answer. Use CB an example with a figure
That should open up discussion
1 I didn't specify a type, just a general statement of where they all fall, I think the Baron 58 by memory was one of the better ones at about 380fpm / sea level
2 Yes of course, most of the schools are at sea level, so thats what they talk about, I was wondering what the speel is for when they depart elsewhere
You may have had " revising the minima " at your school so put down the process they taught you to come up with an answer. Use CB an example with a figure
That should open up discussion
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Just re-reading my post... Sorry, I do sound like an arsehole.
It's a bad habit I seem to fall into.
Sincerely,
Stacks
As per your request:
In order to meet the PANS-OPS requirement of 2.5% in the missed approach sector, the PIC shall calculate the revised approach minima in the event of an engine failure as follows:
Calculate climb gradient available based on OEI climb performance in the AFM/POH using - Gradient = Rate of Climb / Airspeed
Use formula Actual Gradient ÷ 2.5 = XX
Subtract MDA from Missed Approach altitude. The difference being ALT
Subtract XX from 1. The difference being YY.
Multiply ALT x YY. Add this value to the MDA
Example:
Tamworth. MDA = 2000, missed approach altitude = 3500. Actual climb gradient = 2%
XX = 2 / 2.5 = 0.8
ALT = 3500 – 2000 = 1500
YY = 1 – 0.8 = 0.2
ALT x YY = 1500 x 0.2 = 300
Revised approach minima = 2000 + 300 = 2300ft.
It's a bad habit I seem to fall into.
Sincerely,
Stacks
As per your request:
In order to meet the PANS-OPS requirement of 2.5% in the missed approach sector, the PIC shall calculate the revised approach minima in the event of an engine failure as follows:
Calculate climb gradient available based on OEI climb performance in the AFM/POH using - Gradient = Rate of Climb / Airspeed
Use formula Actual Gradient ÷ 2.5 = XX
Subtract MDA from Missed Approach altitude. The difference being ALT
Subtract XX from 1. The difference being YY.
Multiply ALT x YY. Add this value to the MDA
Example:
Tamworth. MDA = 2000, missed approach altitude = 3500. Actual climb gradient = 2%
XX = 2 / 2.5 = 0.8
ALT = 3500 – 2000 = 1500
YY = 1 – 0.8 = 0.2
ALT x YY = 1500 x 0.2 = 300
Revised approach minima = 2000 + 300 = 2300ft.
Folks,
Too many of you are missing the point --- this so called "decision making", after lots of entirely spurious calculations, is irrelevant.
Firstly, there is the plain commons sense ( increasingly less common) embodied in the CAO on page 1 of this thread.
Secondly, you are talking about aircraft that were certified to CARs mostly, not even FAR 23, all the single engine figures are no more than a guideline in the POH or whatever, and are certainly not "certified" performance.
There is no decision to make, if you have an engine failure in cruise in a light twin, you get on the ground at the nearest suitable airport.
Perhaps you should think of it as a failure of a single engine aircraft with an extended glide. The statistics are interesting, relatively there are more fatalities in a light twin after an engine failure than a single after an an engine failure.
It would seem that most of those fatalities are caused by deadly faulty "decision making" by a pilot who completely misunderstands the lack of performance and Vmca traps after an engine failure.
Forget all the fancy (and fanciful) calculations, and get on the ground at the nearest suitable.
It seems this poster's knowledge of what "certification" is about, is of the same standard as his or hers spelling, and creates a lot of "unthinking" pilots, close to 100% of pilots who have flown a light twin.
Tootle pip!!
PS: I am speaking from experience, not theory.
Too many of you are missing the point --- this so called "decision making", after lots of entirely spurious calculations, is irrelevant.
Firstly, there is the plain commons sense ( increasingly less common) embodied in the CAO on page 1 of this thread.
Secondly, you are talking about aircraft that were certified to CARs mostly, not even FAR 23, all the single engine figures are no more than a guideline in the POH or whatever, and are certainly not "certified" performance.
There is no decision to make, if you have an engine failure in cruise in a light twin, you get on the ground at the nearest suitable airport.
Perhaps you should think of it as a failure of a single engine aircraft with an extended glide. The statistics are interesting, relatively there are more fatalities in a light twin after an engine failure than a single after an an engine failure.
It would seem that most of those fatalities are caused by deadly faulty "decision making" by a pilot who completely misunderstands the lack of performance and Vmca traps after an engine failure.
Forget all the fancy (and fanciful) calculations, and get on the ground at the nearest suitable.
Tottaly (sic) agree with this, It´s quite unthinkable to fly a supposed certified aircraft on one engine that can´t mantain (sic) a steady climb...
Tootle pip!!
PS: I am speaking from experience, not theory.
Last edited by LeadSled; 20th Dec 2012 at 23:21.
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Re: expected performance - I know at least one person is going to shoot me down here, but here goes.
First off, I know the regs, I know what the aeroplanes are certified to, and on a purely regulatory level, in a near-perfect world, pilots would never fly an aircraft that they weren't assured could meet the climb requirements.
Take two "identical" aircraft, however, let's say PA31s with adjacent serial numbers, same book figures, same everything, built 30 years ago... Put them in the cruise at the same power settings... And one will TAS 20 kt more than the other, as its airframe isn't bent, and it has fresh engines and props.
Is anybody seriously contending that these aircraft should expect similar OEI performance, or indeed performance anywhere near the book figures? How many 100s of stories have you heard of PA31s skimming the treetops and struggling to climb with BOTH engines operating?
Again, before I get shot down too hard, I DON'T AGREE that we should accept this... But unfortunately it's the sad truth, and acknowledged by nearly every pilot I've flown with, especially in the really old bangers in ISA+20 conditions up north. And the really really sad truth is that if you did the "right" thing and refused to depart unless you were assured of meeting the book figures, you can expect a significant reduction in your flying hours.
Of course, as soon as you start flying aircraft under 20.7.1B, that attitude completely disappears (as it rightly should).
PLEASE NOTE. I'm not disagreeing with anybody in particular here. Just making the point that, as bad as it is, there are plenty of (piston) aircraft out there doing IFR CHTR every day, that in conditions they regularly fly in will NOT perform as per the requirements. Not sure how this can be denied.
First off, I know the regs, I know what the aeroplanes are certified to, and on a purely regulatory level, in a near-perfect world, pilots would never fly an aircraft that they weren't assured could meet the climb requirements.
Take two "identical" aircraft, however, let's say PA31s with adjacent serial numbers, same book figures, same everything, built 30 years ago... Put them in the cruise at the same power settings... And one will TAS 20 kt more than the other, as its airframe isn't bent, and it has fresh engines and props.
Is anybody seriously contending that these aircraft should expect similar OEI performance, or indeed performance anywhere near the book figures? How many 100s of stories have you heard of PA31s skimming the treetops and struggling to climb with BOTH engines operating?
Again, before I get shot down too hard, I DON'T AGREE that we should accept this... But unfortunately it's the sad truth, and acknowledged by nearly every pilot I've flown with, especially in the really old bangers in ISA+20 conditions up north. And the really really sad truth is that if you did the "right" thing and refused to depart unless you were assured of meeting the book figures, you can expect a significant reduction in your flying hours.
Of course, as soon as you start flying aircraft under 20.7.1B, that attitude completely disappears (as it rightly should).
PLEASE NOTE. I'm not disagreeing with anybody in particular here. Just making the point that, as bad as it is, there are plenty of (piston) aircraft out there doing IFR CHTR every day, that in conditions they regularly fly in will NOT perform as per the requirements. Not sure how this can be denied.
--- that in conditions they regularly fly in will NOT perform as per the requirements.
As you know all the "requirements", would you like to spell them out, starting with the "certification" requirements that these small twins are required to meet --- by FAA, and for IFR operation is AU.
Tootle pip!!
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Actually the only "requirement" I was thinking of is the missed approach climb gradient, as that's what the thread is about (sort of). I know we can adjust minima... But if the aircraft can't actually guarantee a climb in the first place, or performance is "unknown"...
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Revising the minima in most situations is idiotic.
If you're inbound somewhere OEI with weather close to the minima and you have fuel and performance to go to an alternate - then go to the alternate.
If you don't have fuel or performance to go to an alternate, you are committed to land at the destination - so either hold until the weather is better or land irrespective of the minima if weather is getting worse.
How does raising the minima help in either case?
Pretty much the only time i would raise any minima is if i was doing an AEO approach (in training) where weather is close to minima and i was planning a missed approach anyway. That way, i could suffer the engine failure anytime and still achieve terrain clearance.
The diversion to the good weather location in the OPs question is bleedingly obvious.
If you're inbound somewhere OEI with weather close to the minima and you have fuel and performance to go to an alternate - then go to the alternate.
If you don't have fuel or performance to go to an alternate, you are committed to land at the destination - so either hold until the weather is better or land irrespective of the minima if weather is getting worse.
How does raising the minima help in either case?
Pretty much the only time i would raise any minima is if i was doing an AEO approach (in training) where weather is close to minima and i was planning a missed approach anyway. That way, i could suffer the engine failure anytime and still achieve terrain clearance.
The diversion to the good weather location in the OPs question is bleedingly obvious.
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Slam Click - you might have to eat those words.
Any single engine climb certification is done with gear up at MTOW, and one engine feathered. Furthermore, FAR part 23 doesn't hardly require any climb gradient below 6000lb MTOW (which is most twins) - only 1.5 percent climb at a VSO (stall speed landing configuration, "stuff out") above 61kts. Below 61kts (more light twins in this category than the other, is my guess), there are no climb requirements at all. Here's FAR 23:
(a) For normal, utility, and acrobatic category reciprocating engine- powered airplanes of 6,000 pounds or less maximum weight, the following apply:
(1) Except for those airplanes that meet the requirements prescribed in Sec. 23.562(d), each airplane with a VSO of more than 61 knots must be able to maintain a steady climb gradient of at least 1.5 percent at a pressure altitude of 5,000 feet with the--
(i) Critical engine inoperative and its propeller in the minimum drag position;
(ii) Remaining engine(s) at not more than maximum continuous power;
(iii) Landing gear retracted;
(iv) Wing flaps retracted; and
(v) Climb speed not less than 1.2 VS1.
(2) For each airplane that meets the requirements prescribed in Sec. 23.562(d), or that has a VSO of 61 knots or less, the steady gradient of climb or descent at a pressure altitude of 5,000 feet must be determined with the--
(i) Critical engine inoperative and its propeller in the minimum drag position;
(ii) Remaining engine(s) at not more than maximum continuous power;
(iii) Landing gear retracted;
(iv) Wing flaps retracted; and
(v) Climb speed not less than 1.2VS1.
If you have gear down on many of the twins, or they can't feather (Miles Gemini and many other older designs) chances are they wont meet climb gradient, not even at SL. Nor are they required to. As simple as that. You're welcome to try to my Aero Commander and see if you can do it.
It's all academical, but if the gear is down and you have any of these scenarios above - you're landing no matter what.
Any single engine climb certification is done with gear up at MTOW, and one engine feathered. Furthermore, FAR part 23 doesn't hardly require any climb gradient below 6000lb MTOW (which is most twins) - only 1.5 percent climb at a VSO (stall speed landing configuration, "stuff out") above 61kts. Below 61kts (more light twins in this category than the other, is my guess), there are no climb requirements at all. Here's FAR 23:
(a) For normal, utility, and acrobatic category reciprocating engine- powered airplanes of 6,000 pounds or less maximum weight, the following apply:
(1) Except for those airplanes that meet the requirements prescribed in Sec. 23.562(d), each airplane with a VSO of more than 61 knots must be able to maintain a steady climb gradient of at least 1.5 percent at a pressure altitude of 5,000 feet with the--
(i) Critical engine inoperative and its propeller in the minimum drag position;
(ii) Remaining engine(s) at not more than maximum continuous power;
(iii) Landing gear retracted;
(iv) Wing flaps retracted; and
(v) Climb speed not less than 1.2 VS1.
(2) For each airplane that meets the requirements prescribed in Sec. 23.562(d), or that has a VSO of 61 knots or less, the steady gradient of climb or descent at a pressure altitude of 5,000 feet must be determined with the--
(i) Critical engine inoperative and its propeller in the minimum drag position;
(ii) Remaining engine(s) at not more than maximum continuous power;
(iii) Landing gear retracted;
(iv) Wing flaps retracted; and
(v) Climb speed not less than 1.2VS1.
If you have gear down on many of the twins, or they can't feather (Miles Gemini and many other older designs) chances are they wont meet climb gradient, not even at SL. Nor are they required to. As simple as that. You're welcome to try to my Aero Commander and see if you can do it.
It's all academical, but if the gear is down and you have any of these scenarios above - you're landing no matter what.
Last edited by AdamFrisch; 21st Dec 2012 at 13:15.
Don't forget the rules vary by jurisdiction. US FAR requirements are a bit different to Oz requirements eg light twin climb performance specs. FARs specify what Adam... wrote, but Oz rules require an ability to either maintain altitude at 5000' (VFR), or climb at 1% at 5000' (IFR). Oz even imposes an IFR climb weight limit on some aircraft that doesn't exist in the US.
Tins,
Australian CASR 23 is FAR 23 by adoption, unique Australian certification standards went in mid-1998.
I'm not eve sure the "old" 5000' climb gradient for IFR (think early model Aztec with one seat removed) applies any longer.
Tootle pip!!
Australian CASR 23 is FAR 23 by adoption, unique Australian certification standards went in mid-1998.
I'm not eve sure the "old" 5000' climb gradient for IFR (think early model Aztec with one seat removed) applies any longer.
Tootle pip!!
Last edited by LeadSled; 21st Dec 2012 at 13:31.
I knew the unique Flight Man. was ditched, but I thought the climb requirements were still extant. See what happens when you leave the country!
Last edited by Tinstaafl; 21st Dec 2012 at 13:57.
Lead Sled you are suggesting that the rules would mandate an option A but you haven't stated what you would actually do?
Far from being irrelevant operational decision making is what that particular CAO is all about. The scenario given is a bit thin on detail but to take a piston twin into an airport S/E with only 100' minimum on an NDB approach is just asking for trouble. If it also had a VOR with a straight-in approach thats a different proposition.
If you find yourself in such a position you do what you have to do to land safely and any other consideration is now irrelevant e.g. cost to the company, media attention,Chief Pilot's view of your flying ability, paperwork to be filled, family commitments etc etc.
I have no idea what the pilot of PGW was basing his decision on but if it was to save the company some time and inconvenience then he paid too high a price.
he or she deems such action to be safe and operationally acceptable
If you find yourself in such a position you do what you have to do to land safely and any other consideration is now irrelevant e.g. cost to the company, media attention,Chief Pilot's view of your flying ability, paperwork to be filled, family commitments etc etc.
I have no idea what the pilot of PGW was basing his decision on but if it was to save the company some time and inconvenience then he paid too high a price.
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Pa 31 series aircraft Option B everytime, I flew these aircraft when they were new, and was not too impressed then, I am no longer a CPL, and could not imagine that they would too impressive now being that most of them would be possibly older than the people flying them
Many years ago in another life I departed Roxy Downs (****e hole)on a hot day with a full load at MTOW in a PA31 (I'll never exactly how heavy we where as no one ever does) & the gear wouldn't retract after T/Off. Both donks where performing well getting max pwr (as far as I could tell) & the A/C barely held level flight in the circuit whilst maneuvering back to land. If I had have had a magneto failure I was doomed never lone an engine failure so I basically accepted that any piston plane was essentailly a SE machine with it's associated non existent performance capabilities when one donk went out for a bex ! Plan yr escape with that in mind then you might live to tell the story.
Wmk2
Wmk2
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Yep I can but agree, out of Meeka hot day density altitude close to the Himalayas,, full load. gear won't retract. landed on cross strip complete with white crosses, problem a little rock had wedged itself into the squat switch actuating lever. No retract =no bloody performance, lucky escape from the coroners attention, it really doesn't take much to turn a good day into crap.