Re-starting an engine in flight if the propellor stops
Thread Starter
Re-starting an engine in flight if the propellor stops
Reading the latest Australian Flying magazine where its flight safety correspondent Jim Davies discussed engine power loss in flight. Each aircraft POH normally publishes an emergency checklist to cover this sort of thing.
Lack of fuel (dry tank) is the usual culprit. One subject that I haven't seen addressed in single engine trainers is where the propeller stops while the aircraft is gliding or during the lead up to practice stall recovery. It was quite common to see this happen in Tiger Moths during aerobatics where the only method to re-start was to dive steeply to force the prop to rotate again. In fact this was part of RAAF training in Tiger Moth days. Part of the pre-aerobatic check was to ensure a suitable forced landing field was within gliding distance.
For what it's worth I thought the following experience might be handy reading for instructor course candidates flying Cessna 152 or 172.
I was teaching a new student how to fly gliding turns just off the coast near Point Cook. We started around 3000 ft and all went well until around 1500 feet I sensed the prop was windmilling more slowly than normal.
I told the student to start climbing but as I said the words the prop stopped and we were forced to resume gliding again. I sent out a quick Mayday on the local frequency and again on an ATC frequency besides squawking 7700.
Trying the starter motor didn't get the engine running so I had to reach over to the student's far side to get to the primer and tried two shots then the starter. We were down to 800 feet and I had already planned to ditch alongside some boats 200 yards off shore. The nearby sports oval at the mouth of the Werribee River was too far away for comfort.
The primer worked, the engine started, Maydays were cancelled and we landed back at Point Cook normally. We were down to around 500 feet when the engine started.
The maintenance release was clean except for one earlier endorsement which had been rectified. What we didn't know was the same aircraft did the same thing to another instructor a few days earlier while on stalling practice in the training area at 3000 ft. In this case the instructor dived the Cessna and got the prop turning again. He refrained from writing up the defect in the maintenance release. That omission nearly cost us wet feet.
A few weeks earlier I had flown the same aircraft and found the primer plunger was hard to operate and on the verge of seizing. Turned out it had been like that for months but not written up.
In the case of our incident it was a stroke of luck that I had endorsed the faulty primer in the maintenance release and it was repaired otherwise we may not have been able to operate the primer plunger when the prop stopped and been forced to ditch. Reluctance to endorse defects in the maintenance release for fear of upsetting someone is a well known problem in GA. Maybe not nowadays but common decades ago. It could save the life of the next person to fly that aircraft.
For flying instructors faced with a stopped prop during training sequences it is worth considering a quick pump of the primer and then start rather than diving and risk losing valuable altitude if it doesn't work.
Lack of fuel (dry tank) is the usual culprit. One subject that I haven't seen addressed in single engine trainers is where the propeller stops while the aircraft is gliding or during the lead up to practice stall recovery. It was quite common to see this happen in Tiger Moths during aerobatics where the only method to re-start was to dive steeply to force the prop to rotate again. In fact this was part of RAAF training in Tiger Moth days. Part of the pre-aerobatic check was to ensure a suitable forced landing field was within gliding distance.
For what it's worth I thought the following experience might be handy reading for instructor course candidates flying Cessna 152 or 172.
I was teaching a new student how to fly gliding turns just off the coast near Point Cook. We started around 3000 ft and all went well until around 1500 feet I sensed the prop was windmilling more slowly than normal.
I told the student to start climbing but as I said the words the prop stopped and we were forced to resume gliding again. I sent out a quick Mayday on the local frequency and again on an ATC frequency besides squawking 7700.
Trying the starter motor didn't get the engine running so I had to reach over to the student's far side to get to the primer and tried two shots then the starter. We were down to 800 feet and I had already planned to ditch alongside some boats 200 yards off shore. The nearby sports oval at the mouth of the Werribee River was too far away for comfort.
The primer worked, the engine started, Maydays were cancelled and we landed back at Point Cook normally. We were down to around 500 feet when the engine started.
The maintenance release was clean except for one earlier endorsement which had been rectified. What we didn't know was the same aircraft did the same thing to another instructor a few days earlier while on stalling practice in the training area at 3000 ft. In this case the instructor dived the Cessna and got the prop turning again. He refrained from writing up the defect in the maintenance release. That omission nearly cost us wet feet.
A few weeks earlier I had flown the same aircraft and found the primer plunger was hard to operate and on the verge of seizing. Turned out it had been like that for months but not written up.
In the case of our incident it was a stroke of luck that I had endorsed the faulty primer in the maintenance release and it was repaired otherwise we may not have been able to operate the primer plunger when the prop stopped and been forced to ditch. Reluctance to endorse defects in the maintenance release for fear of upsetting someone is a well known problem in GA. Maybe not nowadays but common decades ago. It could save the life of the next person to fly that aircraft.
For flying instructors faced with a stopped prop during training sequences it is worth considering a quick pump of the primer and then start rather than diving and risk losing valuable altitude if it doesn't work.
I had the prop stop on a Tiger Moth once, at the top of a stall turn. I didn't know how fast I'd have to go to get the prop windmilling and was at about 1500' overhead the airfield, so just landed and restarted on the ground. Took off and had another go.
'worn throttle linkage' did that to me. fortunately I was doing pre flight checks at the time. I rejected the engineers helpful initial suggestion of not closing the throttle all the way, and a screwdriver fixed the problem.
When learning (Chipmunk - no starter) it was a pre solo demonstration. What surprised was what I thought a very low nose and high speed necessary to get the prop rotating.
Thread Starter
During instructors course training on the Tiger Moth phase at RAAF Central Flying School at East Sale, we were taught how to re-start a stopped prop by diving.
On one particular trip the diving failed to rotate the prop. The instructor calmly told the student (himself an experienced pilot) to patter the subsequent dead stick landing (real one) and after the successful forced landing which was on West Sale aerodrome, ticked the students progress sheet as sequence completed.
Interestingly, there was no requirement to enter anything into the EE77 (maintenance release) since Tiger Moth prop stopping during aerobatics was quite common and not considered a defect.
On one particular trip the diving failed to rotate the prop. The instructor calmly told the student (himself an experienced pilot) to patter the subsequent dead stick landing (real one) and after the successful forced landing which was on West Sale aerodrome, ticked the students progress sheet as sequence completed.
Interestingly, there was no requirement to enter anything into the EE77 (maintenance release) since Tiger Moth prop stopping during aerobatics was quite common and not considered a defect.
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For what its worth the accelerator pump is a poor mans primer too.
The other trick to dive starting is to pull a few g's as you reach the speed that starts to flick it over, this effectively increases the AoA on one blade assisting rotation.
The little Vari-eze will stop rotation (fuel off) at 65 IAS and restart at 160 IAS, requires a few thousand feet though due 70" pitch and 56" dia prop.
The other trick to dive starting is to pull a few g's as you reach the speed that starts to flick it over, this effectively increases the AoA on one blade assisting rotation.
The little Vari-eze will stop rotation (fuel off) at 65 IAS and restart at 160 IAS, requires a few thousand feet though due 70" pitch and 56" dia prop.
Avoid imitations
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It wasn't too unusual for the prop to stop on the Bulldog during a spin. The trick was to forget about trying to restart the engine but concentrate on the spin recovery. Otherwise things could get even more interesting.
Maybe as an instructor on the type you should know the normal idle RPM at best L/D speed, the sound and feel of the Engine at idle in flight etc etc. AND know when it's not right a little earlier BEFORE this happens at low level and catches you out....
The Engine should idle ok during gliding practice ( at what, around 1,000 RPM approx ), if not then the idle speed is adjusted too low. This should have been apparent during the run up checks in the ground when you close the throttle to check the idle speed is around 600 RPM.
Exactly what Sunfish did
What ever happened to running the power up every 1,000' or so to warm the Engine, did you do that?
We're you watching exactly what he was doing or looking out at the view thinking about other things!!
I mean where were you exactly to let this develop?
I'm sorry to be blunt and its your cool head that saved the day but it shouldn't have gotten that far before you noticed and intervened.
Lucky......
The Engine should idle ok during gliding practice ( at what, around 1,000 RPM approx ), if not then the idle speed is adjusted too low. This should have been apparent during the run up checks in the ground when you close the throttle to check the idle speed is around 600 RPM.
Exactly what Sunfish did
What ever happened to running the power up every 1,000' or so to warm the Engine, did you do that?
We're you watching exactly what he was doing or looking out at the view thinking about other things!!
I mean where were you exactly to let this develop?
I'm sorry to be blunt and its your cool head that saved the day but it shouldn't have gotten that far before you noticed and intervened.
Lucky......
Last edited by ACMS; 26th Jun 2016 at 08:52.
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What ever happened to running the power up every 1,000' or so to warm the Engine, did you do that?
Last edited by sheppey; 26th Jun 2016 at 12:59.
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The Victa 100 would go VERY close to VNE to get the propeller to turn once it was finally stopped.
The primer trick was never taught as using the starter was not considered as part of the so called exercise??
Long time ago, might be confused, 1967.
The primer trick was never taught as using the starter was not considered as part of the so called exercise??
Long time ago, might be confused, 1967.
Ah yes, I've had it in a Victa on a stall turn as well. The second half of the manoeuvre got it turning again without needing anything special from me. So, nothing close to Vne, in my experience at least.
I'm a little surprised only young mic brought up increasing G. We were taught that, I think, during instructor course. If the prop got stuck up against compression stroke even Vne wouldn't budge the prop but the moment we added g it would start windmilling. We didn't dwell on it much since we were mostly starter equipped.
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The reason that the airflow changes from pitching hard nose up in a fixed wing (not so much the amount of "G" therefore induced) is more likely to turn the prop/engine over is perhaps more widely understood by helicopter pilots. 
Sheppey-----well done you win the pedantic award of the day, yes it was to make sure plugs weren't fouled up and you, more importantly, had power available when you needed it. I guess the term "warming the Engine" is a little misleading but that's what they simply called it back then.
Either way it should be done during a glide.........before it gets too low.....
So, my point still stands......sarcastic tone or not.
Didn't learn ab-initio on Cessnas mate, sorry to disappoint, I guess you had a 50/50 chance!!
Either way it should be done during a glide.........before it gets too low.....
So, my point still stands......sarcastic tone or not.
Didn't learn ab-initio on Cessnas mate, sorry to disappoint, I guess you had a 50/50 chance!!
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We also called it "warming the engine" too, a generic term used describe good handling.
But you know, carby heat at idle is sometimes just not enough. Happened to me once on the downhill with full heat, pushed the throttle to the wall and nothing happened...
But you know, carby heat at idle is sometimes just not enough. Happened to me once on the downhill with full heat, pushed the throttle to the wall and nothing happened...
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I see where OWT's breed 
Warming? Plugs?
Carby heat perhaps but if the mixture was not pushed all the way in the carb temp would be warmer in all cases.
Get some science going here folks not just OWT's handed down hey.
Warming? Plugs?
Carby heat perhaps but if the mixture was not pushed all the way in the carb temp would be warmer in all cases.
Get some science going here folks not just OWT's handed down hey.