Partial EFATO in a single

[Genghis the Engineer]

It occurred to me, on Sunday, a short while after my third urgent landing of the year - in this case a Rotax 503 engined Thruster* that decided to rough-run at 400ft just after take-off from a short farm strip, that there's a teaching point here.

Most of my engine problems over the years have been other-than the classic sudden engine failure. This seems to have been a fuel supply fault preventing the carb bowls from both filling properly at climb power and attitude.

I know how *I* handle these - maintain as much height as possible whilst positioning from landable field to landable field until I'm able to make a runway, then taking an approach (straight in or constant aspect) to that which is consistent with still making the runway if the engine stops altogether at any point. A handful of such events and no scratched aeroplanes suggests to me that I'm getting this about right. I'd do something similar if worried that I'd f*****d up my fuel planning and was at risk of fuel starvation. (Actually I did do this a couple of years ago when I realised halfway through testing an Auster** that the fuel system was only drawing from one fuel tank, so my conservative plan to land with 40% of the fuel I'd started with wasn't enough!)

In teaching terms however, I've never come across somebody teaching this as an exercise. Field-to-field has mirrors in what we do recovering from a PFL, whilst everybody practices glide approaches from time to time. But as a complete set it's not a combination that I've ever come across being taught or even particularly talked about.

Should we?

G

*For the record, not my aeroplane; I was doing the annual Permit to Fly air test, which I declared the aeroplane to have failed.
** Nor was the Auster.

[blagger]

I frequently give my students and exam candidates a partial Rather than full EFATO on take off, in general the recognition and handling of it is dreadful, the industry only ever seems to teach full EFATOs on take off. I have spoken to the CAA Senior FE about this.

What you describe as a method of handling this seems to be a turn back with option of field landing along the way?

In an SEP if you have an engine issue my view is you need a plan of action, then get on with it. Field to field stuff is just prolonging the time spent dicking around at low level increasing the time the average PPL driver will have to make a hash of it and stall / spin in.

[Genghis the Engineer]

What you describe as a method of handling this seems to be a turn back with option of field landing along the way?

Other way around really; using the limited available thrust to position for a good field landing, but keeping the option of a runway landing available if that presented itself. It did, particularly in this case because it was a zero wind day so a turnback became a viable option. It wouldn't have been with a full engine failure.

A partial engine failure away from the field I think I'd treat similarly, but "crashing" onto an airfield has a lot going for it - a runway is a known safe surface, and the rescue services know where to find you.

Both the Thruster and the Auster I could have made a field landing - but neither did I eventually need to. Whilst I could have justified making a field landing in either case, it would not have been the best outcome.

G

[Whopity]

The problem with partial engine failures is that there are so many different possibilities, you really can't practice for all of them. I was always taught that if you suffer a partial failure you treat it as the worst case and use the EFATO training you have been taught and practiced. In the real event you may have a little bit of power to get you over the hedge but one shouldn't rely upon it. At the end of the day, you do what you can with what you've got and by closing the throttle you can revert to what you have been trained to do.

[A and C]

Than sounds like a very wise course of action.

[PowerDragTrim]

There are millions of variables in this case, so the safest is to get the situation back to something 'routine'.
My advice would be use available power to get down to the best field close by and then glide in. But always land asap - you may still have a potential full failure awaiting you!

[Big Pistons Forever]

Unfortunately flight training tends to teach engine failures as binary, engine is either working perfectly or it has suddenly and totally failed.

However sudden complete failures with no warning is the least likely real world scenario.

A partial loss of power is a much more likely occurrence. I specifically address the partial engine failure in my training starting with a discussion about knowing the minimum power required to maintain level flight. Obviously a deterioration of
power below this value means you are no performing a power assisted forced approach.

Stable power above this value now gives you some real options and so you need to decide on a where you are going ASAP. This would normally be the nearest airport with landable terrain between you and it. Once the situation has stabilized you would then do a cause check to see if you can identify the problem and restore more/full power.

[RTN11]

The only time I had anything near this was as a total rookie with around 60 hours, I hadn't set the throttle friction on a 172, and the steep climb angle caused the throttle to slide back. I never took my hand off the throttle during the climb again!

My advice would be use available power to get down to the best field close by and then glide in. But always land asap - you may still have a potential full failure awaiting you!

For me this is the best advice, and what I would teach. I may well offer a partial power reduction as an EFATO, but would still expect the student to take whatever is in front of them. Aircraft can be replaced, people cannot, I'd rather a student hobble away from a wreck a couple of miles away rather than stall trying to nurse a dodgy engine back to the airfield.

[Big Pistons Forever]

I do not like the idea of saying treat partial engine failures as EFATO's. If you are cruising along at 2400 RPM and the engine loses say 200 RPM but stays steady at 2200 RPM, you have by definition suffered a partial engine failure, but it does not seem reasonable to just go ahead and immediately land on what ever field is in front of you.

In the event of an uncommanded reduction in power the first thing you should do is apply full carb heat, because if it is carb icing you may not have much time to clear it before the engine stops. Yes you should always be looking for a landable area and point the airplane at it, but you should be also be sensible and do some troubleshooting as the partial failure may be self induced. This is why it is important that the students can do a good cause check and understand what they are doing/looking for when they are checking things.

[Pilotage]

I tend to agree with you Big.

You should always be flying any single as if the engine might stop NOW, anyhow. But whilst you have any power, using that to improve the situation by positioning better for the field, or for a better field, makes a lot of sense.

And if that positioning from field to field, always expecting the engine to stop NOW makes the last field a runway, surely that suddenly improves the whole situation massively.

And as you say, using the time and power available to check for fault and rectify it, IF high enough with the landing option sorted out first, should be part and parcel of all pilots skillsets.

P

[Tinstaafl]

Like Big Pistons, I don't think all partial failure should be handled the same as a complete failure. I think partial failures have two divisions: CAN maintain altitude, and CAN'T maintain altitude.

In the CAN'T case then it's like a total failure (but with better glide performancen, and an extra option to adjust vertical navigation)

In the CAN case then an immediate landing is not necessarily the best course of action. There is an option to continue flight, albeit with a considered possibility of it becoming a forced landing anyway. I've had a partial failure in an A36. Even though the engine had a whole cylinder separate, the aircraft was still flyable. Over rough terrain at night - as I was - I'm certain that choosing an immediate forced landing was, and still is, the worst option. Instead I was able to make it to an airfield. But the whole way I was prepared for it to become a forced landing, and tracked as best I could via open areas.

[Piper.Classique]

Like Big Pistons, I don't think all partial failure should be handled the same as a complete failure. I think partial failures have two divisions: CAN maintain altitude, and CAN'T maintain altitude.

And of course, is it looking like it will keep running, or are things deteriorating?
Are you going to teach every single failure mode in the air, or are some things going to have to be discussed on the ground only?

I've had a low oil pressure/high temperature scenario in IMC , after several times round the hold, where I simply let the student fly the published approach. We broke cloud at 900 feet and went ahead and landed. That was a mangled piston, funnily enough the engine didn't sound rough. Needed a new one, though.

I've had a throttle jam solid at 1800 rpm after reducing power to avoid being sucked into cloud in the cub, just after an engine change. That one was easy, take it home.

Third one was both plugs failed on the same cylinder on a Pa 28, which was boneshakingly rough but would even climb a little. That one we got home too, flying from just possible field to just possible field (Herefordshire, after two weeks solid rain)

But the OP (welcome back GTE) spoke of EFATO. That one is where I say to my students that at this point the aircraft is now the property of the insurance company. Fly it down to the ground, try to crash gently.