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-   -   Minimizing risk in the case of an engine failure (https://www.pprune.org/private-flying/631093-minimizing-risk-case-engine-failure.html)

Pilot DAR 31st Mar 2020 01:05

Minimizing risk in the case of an engine failure
 
From time to time, I heard expressions of concern about an engine failure (in a single) becoming a serious accident. Yes, I accept that it is possible to fly single engine planes in a way which increases (or decreases) risk in the case of an engine failure. Absolutely preventing an engine failure is not possible. What do pilots do to minimize risk of an accident resulting from an engine failure?

For myself, most important, avoid steep climbouts after takeoff, less Vx, as much Vy as possible, while clearing the obstacle. Avoid at all costs the kind of long, steep climbouts seen in many of the the "Valdez STOL competitions"!

Andy H 31st Mar 2020 08:41

The most important way to minimise risk in the case of an engine failure is to practice engine failures. Often.
I know it helped in both my cases !

Jan Olieslagers 31st Mar 2020 09:04

Cruise high! Who was it that said "airspeed is safety, altitude is life insurance"? I am often amazed at how low some club fellows fly, 1000' not uncommon. Myself will (where allowed) keep at least 1500', and prefer 2500 or so; or even higher.

And yes, practice engine out landings, yes.

Hot 'n' High 31st Mar 2020 10:14


Originally Posted by Pilot DAR (Post 10733937)
..... What do pilots do to minimize risk of an accident resulting from an engine failure?.......

I started flying in gliders and so, particularly on x-country flights on an iffy day (or, rather, one which was turning iffy!!!) I always flew with one eye on the airspace (lookout etc, etc) and the other eye on the ground looking at what is around just in case the lift-fairies (thermals) decided to finally let me down (you got bonus points - and bought a bit less beer - if there was easy access for a retrieve crew as well!!!). :ok:

Perhaps no need to be quite so obsessed in a single but, still, route sensibly - even avoid flying over large forest areas, route round really hilly country where perhaps not too many flat areas (or even avoid flat areas which are really boggy/marshy), avoid built up areas and shorten routes over water and so on. Oh, and always look out on the departure for the next available landing area on climb-out!

Finally, make a decision to quit doing restart checks early (you can always go back to them again if you have time later) and plan your FL when you have good height/vis/time with, hopefully, more than 1 option just in case Plan A goes pear-shaped towards the end (ie field conditions not as they first appeared).

And try fly the approach as if it is a "normal" engine-off SF landing - the fact it is not on an airfield is now irrelevant (particularly to the plane who has no idea where you are about to plonk it down!) so concentrate on aviating to the best of your ability! My first off-field landing saw me slightly unsettled until I said "FFS H 'n' H, you're just landing a bl**dy glider! That's all! You've done it loads of times before! Just land the bl**dy thing like you normally do - except, do try and miss the bl**dy sheep!!!!!". :p

Just some thoughts - in summary, it's the planning ahead which will make things safer! H 'n' H

TheOddOne 31st Mar 2020 10:16

Our examiner made me put an engine failure checklist on our notice board. Actually, I really like it, so it's stayed up.
Before it goes on to the actions to be taken in the event of an engine failure,
The first lines say:

Prevention.

! Regular maintenance
2. Use approved and inspected fuel
2. Pre-flight checks, including fuel calculation
3. Proper operation in flight, including ensuring tank selection

As you can see, 3 out of the 4 preventative measures (and probably the other one, as well) involve fuel. In the UK, this month's Flyer magazine (other magazines are available) highlights accidents that all involve fuel especially contamination thereof.

The only thing I'd add would be regular, frequent flight operation of the engine. The received wisdom is that Lycoming engines particularly are susceptible to cam shaft corrosion if left for periods without flying. There was a tragic fatal crash of a PA28 Arrow following engine failure a couple of years ago in Eastern England. The aircraft had stood unflown and neglected for a long period.

TOO

V1... Ooops 31st Mar 2020 11:21


Originally Posted by Pilot DAR (Post 10733937)
...as much Vy as possible, while clearing the obstacle.

I think that maintaining Vy following takeoff until reaching at least 1,000 AGL is very important - whether in a single or a twin.

Altitude is potential energy, and the more potential energy you have, the more options you have. Speed, on the other hand, is kinetic energy, and the more kinetic energy you have, the bigger a hole you make when you hit the ground.

Furthermore, in most singles and small (12,500 lb or less) twins, Vg is usually pretty close to Vy, which means one less thing to have to do (adjust speed) following an engine failure.

For many years, I taught pilots of large twin-engine commuter category aircraft in classroom & simulators. Many pilots would tell me they always wanted to get well above Vy after takeoff for various reasons - time to respond to an engine failure, keeping a distance above Vmc, etc. My response was always the same: "If you know in advance that you are going to have an engine failure (one or both) 30 seconds after rotation, what speed would you choose to climb at?" After thinking for a few moments, they usually responded "Vy". If they didn't, we'd go into the simulator and fly the exercise (engine failure - one or both - 30 seconds after takeoff) using their preferred technique, and using Vy. The results were always better when Vy was used.

Michael

fireflybob 31st Mar 2020 11:41

Partial engine failures carry a much higher fatality rate than total engine failure and yet, statistically, are 3 times more likely to happen (from an Australian study which I don't have to hand right now).

So think about how you would handle losing significant power on the climb out after take off and practise such scenarios.

Also if en route and you experience a significant loss of power head for the nearest airfield maintaining (or even gaining) height and on reaching the overhead close the throttle and perform a forced landing there. If you opt for a normal join the engine might quit halfway round the circuit. Of course you also need to apply usual judgement in having a look round for cause of failure and do stuff like switching the fuel pump on, if applicable, and change fuel tanks etc. Beware "get home itis" and trying to return to base too whilst you pass safe landing sites.

Pilot DAR 31st Mar 2020 12:10


The most important way to minimise risk in the case of an engine failure is to practice engine failures. Often.
Yes, Me too! I try to do a power off landing from downwind at least every other flight, just for practice. You can't usually do it at an airport with traffic, but any time you have the circuit to yourself, practice!


Altitude is potential energy, and the more potential energy you have, the more options you have. Speed, on the other hand, is kinetic energy, and the more kinetic energy you have, the bigger a hole you make when you hit the ground.
Yes and no... If you have too much speed as you approach to flare, you can bleed it off with drag, or at worst, touch down parallel to the surface too fast. If you have too little speed when you approach to flare, you are going to make a mark when you hit the ground. Considering clearing the proverbial trees at the departure end of the runway, I'd rather clear them by a few leaves with more airspeed, than clear them by 100 feet at Vx. If the engine were to quit a hundred feet above those trees, I'd waste that 100 extra feet jamming the nose down trying to accelerate in the glide to a gliding speed sufficient to flare. It would be a very unstable approach to a gliding flare.


Many pilots would tell me they always wanted to get well above Vy after takeoff for various reasons - time to respond to an engine failure, keeping a distance above Vmc, etc.
I agree with V1 Ooops, If you're going to loose an engine in a multi engined airplane anywhere near "low altitude", you'd rather be right around Vy/Vmca, Slower than Vmca is simply dangerous. Faster than Vmca means that you'll have a lot more drag to overcome from the failed engine as you feather it, and it may be difficult to maintain directional control as you slow down to Vmca.

Near the ground, fly the speeds in the POH!

oggers 31st Mar 2020 16:41


Faster than Vmca means that you'll have a lot more drag to overcome from the failed engine as you feather it, and it may be difficult to maintain directional control as you slow down to Vmca.
Eh? Vyse is above Vmca. Why would you be slowing down to Vmca? In terms of directional control, the extra drag of being faster than Vmca is more than offset by the extra rudder effectiveness. Kind of fundamental to know. More speed = more directional control. After clearing obstructions you fly Vy, if you lose a donk you slow to blue line speed - unless you are intending to do a low level Vmca demo.

Pilot DAR 31st Mar 2020 17:31


Eh? Vyse is above Vmca. Why would you be slowing down to Vmca?
Yes, I refine my comment, you're correct. The point I missed making precisely is to not fly significantly faster than the the fastest single engine speed for what you're doing with the plane in low altitude/critical phases of flight, as there will be an increase in asymmetric drag from an unfeathered prop at the faster speed. Yes, increased speed gives more rudder effectiveness, and, more rudder pressure required. I seem to recall getting a pretty tired leg while trimming during some single engine testing in the Turbine DC-3, though the rudder forces lightened with increased rudder deflection! Planes with autofeather are not such a worry in this regard.

Though I do not recall ever testing it, Vyse would be predicated on the prop being feathered. Vmca would be demonstrated before the prop is feathered, though with feathering being an element of maintaining control. If you attempted a Vyse climb without feathering the prop (or couldn't - some Lycomings below a certain RPM) would you have trouble maintaining directional control where flying more slowly would allow you to maintain control more easily? I did some Vmca testing in the Lycoming powered DA-42 during its STC approval, but the details are hazy in my recollection now... The challenge with the Lycoming powered DA-42 is that the power went from 135HP a side to 180HP a side, so there was a lot more asymmetric thrust to overcome. I found by inspection that the less than ideal rudder cable arrangement allowed the rudder pedal to be fully pressed, but the rudder had not reached it's full travel, so "full rudder" was mechanically not available. Vmca was a problem. I did not finish that flight testing, so I don't know what was done to resolve the problem, I just found it...

Dan_Brown 31st Mar 2020 21:22


Originally Posted by TheOddOne (Post 10734348)
Our examiner made me put an engine failure checklist on our notice board. Actually, I really like it, so it's stayed up.
Before it goes on to the actions to be taken in the event of an engine failure,
The first lines say:

Prevention.

! Regular maintenance
2. Use approved and inspected fuel
2. Pre-flight checks, including fuel calculation
3. Proper operation in flight, including ensuring tank selection

As you can see, 3 out of the 4 preventative measures (and probably the other one, as well) involve fuel. In the UK, this month's Flyer magazine (other magazines are available) highlights accidents that all involve fuel especially contamination thereof.

The only thing I'd add would be regular, frequent flight operation of the engine. The received wisdom is that Lycoming engines particularly are susceptible to cam shaft corrosion if left for periods without flying. There was a tragic fatal crash of a PA28 Arrow following engine failure a couple of years ago in Eastern England. The aircraft had stood unflown and neglected for a long period.

TOO

Agreed.

When i was operting single piston engined a/c: the engineering department requested us and we compiled. This we did in an off season with a lot of down time.

Every 72 hours the engine should be started: "run up" and kept running until the engine is at full operating temperature. This was even more important: when the aircraft was in a temperate climate. This action has the effect of reducing bearing corrosion and help teduce the moisture content in the oil.

Failing that: the engine should be inhibited.

"Look after an A/C and it will look after you" Having an aircraft allocated for one's sole use did have it.s advantages!

As for practise forced landings: all good and I agree. However you need to keep shock cooling in mind. Yes they have to be practised of course.

Fly the a/c​​​​​ on, under control. If you have no choice but to fly between trees for eg., do so. You may loose the wings etc., but they will absorb a lot of energy. Good chance of walking away.. Stall it and depart from controlled flight, the likely hood of a favourable outcome are remote. It's the vertical deceleration that does us humans the damage.


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