Skills test Engine Stop / Start

[K1200Sagian]

18 hours into a NPPL, a question.

I looked on the NPPL web site last night to see what the skills test involves.

Point 11. Engine. Stop / Start

(minimum 2000 ft) (using electric starter)

So, this means, I stop the engine off at the examinors request, pull out mixture and throttle, at no less than 2000 ft, get the aeroplane into a glide, put mixture to rich, open throttle a quarter, prime once and lock prime, turn key and hope the engine fires up, fly away?..................

If that is what it takes, that is what I will do, however, I do question the safety aspect.

[bonniejack]

I cannot find this mentioned. Is it SEP NPPL you are doing? I am doing my skills test on Thursday so if this is the case then I am in for a surprise.

[Blinkz]

Nope you won't do this. I mean come on you would shutdown your only source of power, thats just stupid! In a multi engine test you can be asked to shutdown one of the engines and restart it but you won't be asked to do it in a SEP. Restarting engines in the air isn't the easiest things to do, so you certainly won't shutdown your only to see what happens!

Although, it depends what test you are going for? If its the SLMG then it is possible you will be asked to do that since the aircraft is designed to be a glider as well! I wouldn't like to do it in a warrior tho.....

[K1200Sagian]

Whoops.............

Just looked at the test form notes on the web site www.nppl.uk.com (http://www.nppl.uk.com) , and there are notes for SLMG but there are no notes for SSEA.

Reading point 10. Fly a pre planned mini glider nav ex. should have given it away.

Just need the NPPL to update the web site, to give the same notes for the NPPL skills test

Hope it goes well for you thursday.

[bonniejack]

The syllabus for the SSea is the first in the list. Tanks for the luck, of course I won't need ithttp://www.pprune.org/forums/images/icons/winksbuddie.gif

[BackPacker]

So, this means, I stop the engine off at the examinors request, pull out mixture and throttle, at no less than 2000 ft, get the aeroplane into a glide, put mixture to rich, open throttle a quarter, prime once and lock prime, turn key and hope the engine fires up, fly away?..................

Okay, it's established you don't have to do this on the SEP exam.

But, just in case you have to do this for real, someday, for instance because you mismanaged the fuel in your PA-28 and ran one tank dry:

As long as you maintain a reasonable speed (best glide will do), the engine will windmill. Usually at an RPM far greater than what the starter motor could deliver. Also, the engine is still warm (if you react quickly enough) so there's no need to prime. Just make sure mixture is rich, fuel selector is on a non-empty tank and the electric fuel pump is on. Leave throttle where it is and the engine will catch again.

I fly aerobatics in an R2160 without an inverted flight system and we do push negative g's for short periods. This interrupts the fuel flow to the engine, floods the carbs etc, so the engine will stop producing power. But it does keep on windmilling. All we do is pull the throttle to avoid the 100LL smell from the overflowing carbs. As soon as positive g is restored, the engine will catch again in a second or two. Should the engine stop completely then once positive g is established all we need to do is flick the starter switch quickly. As soon as the engine is past that first compression the airflow will ensure that the engine will windmill again.

And if you don't believe me, here's something that you could try (with an instructor on board, obviously). In level cruise, at a safe height (and 2000' seems very low to me), pull the mixture all the way back. Engine will stop producing power and windmill. Trim for best glide. Push mixture all the way in again. Engine will work again. Simple. (Don't do this too often though. The cooling/heating cycle associated with this is not good for the engine.)

[K1200Sagian]

I belive you!!!

[Saab Dastard]

And if you don't believe me, here's something that you could try (with an instructor on board, obviously). In level cruise, at a safe height (and 2000' seems very low to me), pull the mixture all the way back. Engine will stop producing power and windmill. Trim for best glide. Push mixture all the way in again. Engine will work again. Simple.

Preferably in the overhead of your home field! Always expect the worst. ;)

And 2000 feet should be more than ample - you should be able to glide it in from 1000' anywhere in the circuit. Except at Elstree, when you may be quicker going to Denham, or Panshanger. :p

SD

[BEagle]

I can vouch for the mixture knob demo in a PA28....

On old models, it was a plunger. Student calls 'carb heat hot' and pulls mixture knob fully out.....on base leg.

The engine immediately lost all power - which was restored half-a-heartbeat later when I pushed it back in!

"Wrong knob, Knob! Bet you won't do that again!" quoth I.

[Mariner9]

I spent ages agonising whether I should try stopping the engine aloft to properly simulate the glide. Eventually I decided I was going to do it, so climbed to 8000' over a local farm strip (where I often do PFL's right down to landing), then idled back down to 7000 to cool the engine a little (Rotax so water cooled but I decided to be gentle as possible) before switching off.

First thing to report was that I had to fly really slowly (almost to the stall) to stop the prop windmilling. Once the prop had stopped however, the decent rate at best glide speed improved significantly, but was still greater than a normal idle glide. Had great fun gliding around for ~ 5 minutes, experimenting with different speeds to find the optimum glide speed, found it to be more or less what the POH said it should be. Also cycled the wobbly prop, was great for adjusting decent rate without retrimming, could be very useful in a real forced landing.

Finally decided to restart by windmilling - had to dive to 120kts before prop started to turn again, but the engine fired instantly.

Very useful experience IMHO, I now know the true glide characteristics of my aircraft should I ever face an engine failure. No doubt a controversial action though, cue loads of posts.....:E

[stiknruda]

Useful info on Pprune!

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Recently a topic digressed into the merits of "fish-tailing" to restart an engine in flight.

Saturday last I was participating in an aerobatic competition. Underneath me is an 800 metre runway and despite the very strong cross wind I've landed on it from glide approaches twice in the past few hours.

During the first unknown sequence my engine stopped.......

Figure one was a downwind roll of the top to firure two a one turn erect spin to figure three a half Cuban.

I had entered the aerobatic box at 1600', 2600rpm/160mph. Because I was going downwind I was really steaming through the box, pulled up into a half loop, right rudder, full left aileron and rolled erect on the reciprocal heading at about 80mph and at a nose-bleeding 2300'.


Power to flight idle, keep pitching the nose up to arrest any tendency to descend until I can feel the buffet - quick ASI check shows 60mph, stick almost full back. Full left rudder and the stick fully back should have been the next thing to do BUT the aeroplane decided that it wanted to spin to the right - just as it began to depart I hoofed in bags load of left pedal and brought the stick fully back.

The aeroplane began to spin but I noticed that something wasn't right - somebody had turned the music off! After half a turn I began to feed in forward stick to make the spin exit more vertical.

Then and only then did I realise that whoever had turned the music off had left a piece of wood strapped to the front of the aeroplane where the propeller disc should be.....£*** me that is the propeller

Confusion really began - what to do, what to do? At this stage I am lying in fifth place and a good unknown sequence should see me with a podium place.

Should I try and restart the engine with the key?
Should I complete the spin power off then pull to the horizontal then restart before the next figure and hope I had sufficient speed for a half Cuban?
Should I abandon the sequence and land and explain that a technical problem caused me to abort - the rules do allow for this.

By this stage the aeroplane is heading downhill, picking up speed and I realise that I've over-rotated by 180 degrees and will have scored zero for this maneouver.......preservation takes over and I stop the spin and concentrate on building the speed. At 1200' I am doing 110mph and the prop hasn't moved, milliseconds later I am through 1000' and nearer to 125mph and still nothing.

At 800' I decide that if nothing has happened by 500', I shall pull out of the dive and set up a circuit to land from. This does not overly faze me. What fazes me is my inability to move my left hand from the throttle and forward 13" to the starter key.

At 700' - like a bolt from the blue I realise that fishtailing might help. I press right rudder and then left and suddenly the dead stick starts to flick over, one blade, two blades and roars into life.

I pull to horizontal just under 600' and with almost 150mph on the ASI.

I performed three wing rocks to signify that I was breaking my sequence. I then re-positioned myself and after a further 3 wing rocks flew the rest of the sequence.

Unfortunately the stationary prop blunted my concentration and the rest of the sequence was not flown with the necessary accuracy to maintain my placing.

I landed after the sequence and gave a silent thanks to the good burghers of Pprune for mentioning FISHTAILING recently. It certainly saved me some embarrasment!

Stik

ps - I didn't come last!!

[Fuji Abound]

Occasionally I used to sit in the back when an instructor at my local field was teaching.

I recall him turning off the engine on one particular student whilst down wind in the circuit and restarting the engine during the ground roll.

Apparently it was something he did regularly.

[carbheathot]

recall him turning off the engine on one particular student
On my GFT many moons ago, the examiner distracted my attention,reached down and switched off the fuel flow. Cessna spluttered along for a few minutes then stopped.Certainly sharpened the concentration.Wonder if it was the same guy

[Fuji Abound]

What was his first name?

[carbheathot]

His name was Andy

[BackPacker]

I landed after the sequence and gave a silent thanks to the good burghers of Pprune for mentioning FISHTAILING recently. It certainly saved me some embarrasment!

Never heard of the word fishtailing before in this context. I guess you mean yawing the aircraft left to right and back? I can imagine that works well, since the prop is now blown on sideways, with more pressure to push it through its first compression.

One word of caution - this manoeuvre creates immense sideways forces on the tail and torque on the aft fuselage. Va is defined as the speed where the wings stall before the load on them becomes excessive, but flying below Va does NOT automatically extend the same protection to the rudder. In fact, aerobatic aircraft have a specific speed limit, usually well below Va, for manoeuvres such as flick rolls which exert the same force on the rudder.

I don't know what sort of airplane Stik flies, but from his experience I guess it's a very capable aerobatics plane which doesn't get bent by a fishtail at 150 mph. But if you do the same thing in the average spamcan, you might lose the whole tail section instantly. Not good.

[TheKentishFledgling]

I don't know what sort of airplane Stik flies, but from his experience I guess it's a very capable aerobatics plane which doesn't get bent by a fishtail at 150 mph. But if you do the same thing in the average spamcan, you might lose the whole tail section instantly. Not good.

I think he was in a 172 that day :E

tKF

[TheOddOne]

During my Flying Instructor course this Summer, we went through the prop stopped routine. Climb to 5,000', fly 1KT above teh stall and pull the mixture to ICO. hold the attitude without stalling 'til the prop stops (quite difficult). Once stopped, nose over to the yellow arc on the ASI (almost vertical down. The prop still won't start windmilling. What's required is exactly what Stik did, only in this case at 90deg, by pushing & pulling on the elevator. This induces different angles of attack over the prop until you hit the sweet spot and it starts going round again. The resultant recovery is more extreme than from the spin series you need to do for the FI rating. This may consume around 3,000', recovery at around 2,000'. Fortunately, you only have to do it once.

What this graphically demonstrates to me and is borne out by Stik's story above, is that re-starting a stopped prop is on the edge of possibility and is only achived by extreme manoeuvring. I'd definitely NOT like to try it in a PA28, I've heard stories about their wings being pulled off from extreme dive recoveries.

Cheers,
TheOddOne