Prop failures Scare me

[pelmet]

Depending on where the failure is, an engine can completely depart the aircraft. While some damage can be hidden from pre-flight inspection. I do try to check the blades carefully on small aircraft including the face of the blade and try not to start the aircraft or do a run-up over stones(of which there can be a surprising amount on some paved areas. Any other suggestions or stories(for aircraft big or small)?

"C-GWCP, a Piper PA-32-300 aircraft operated by MHA Enterprises, was conducting a VFR flight from St. Theresa Point, MB (CYST) to Winnipeg/St Andrews, MB (CYAV). While cruising en route approximately 12 nautical miles North East of Gimli Industrial Park, MB (CYGM), the aircraft experienced strong vibrations from the engine area. The pilot diverted to CYGM for a precautionary landing. During the approach and landing, the vibration increased in intensity as the engine power was reduced. The pilot turned off the magnetos during the landing roll and cleared the runway onto adjacent grass. Post-flight examination determined that an 8 inch section of one propeller (Hartzell HC-C3YR-1RF) blade tip was missing. The operator will submit an SDR to Transport Canada."

[cgzro]

And so they should. There are a few areas on a plane that if they break everybody dies and a propellor blade separation in flight is one of them. In the aerobatic world we've seen more than a handful of blade separations and it takes the engine off the plane when it happens. Wing spars, vertical fin, stab spars are other deadly areas but unlike propellor blades they can't easily be inspected during a pre-flight. Propellor blades are mostly accessible to inspect and un-smothed out nicks in the leading edge are a serious concern. Likewise in the constant speeds props like the HC series grease or oil being slung by the blades is also a worry. The grease will be slung all over the plane as teeny tiny streaks often far out down the leading edge (can be mistaken for bugs)... its a sure sign you need to pull the prop. On the HC series the blades and hub are painted that dull grey colour for a reason. It makes crack detection much easier. Any pencil like lines on the hub are aluminum oxide power fretting out of the crack and is cause for grounding, as are any visible cracks on the blades anywhere on their length, this should be part of a daily or preflight inspection. Every small plane or helicopter pilot should have a bright LED flashlight and shine it into the prop hub (and many other areas of the aircraft) looking for problems at least daily, if not every flight if the plane is being flown hard.

[oldtimer]

I have seen some horrible nicks and gouges on the propellers of seaplanes, usually caused by operations in rough seas and by careless pilots. Never heard of any blade separations but that is not to say they have not happened.
Heard of a pilot who flew a Cherokee Arrow on a 2+ hour flight with the tip of one prop blade missing. How can a pilot not notice the extra vibration.

[dogfood]

Delete

[cgzro]

If nicks and gouges are properly smoothed out and tapered its not a problem. The propellor manufacturers specify how deep a nick/gouge can be and where and what taper you need to make to smooth it out. Basically rough edges cause cracks to start so they smooth them down and polish them away.

[crazyaviator]

SMOOTHED out may be a poor term for the fix! One has to remove the aluminum to just below the base of the crack and blend the area without sharp areas. In the old days, AME s would take a screwdriver and "dress" the LE of the prop where the nick is , smoothing the offending gouge and hiding the crack, thereby allowing crack propagation without detection till the bitter end !

[J31]

SMOOTHED out may be a poor term for the fix! One has to remove the aluminum to just below the base of the crack and blend the area without sharp areas. In the old days, AME s would take a screwdriver and "dress" the LE of the prop where the nick is , smoothing the offending gouge and hiding the crack, thereby allowing crack propagation without detection till the bitter end !

OLD DAYS! There are still many people out there that still believe that rolling the blades with a screwdriver is a good thing.

DON'T DO IT!

As crazy said you must dress out below the damage with a good file.

[cgzro]

yes, you have to file the crack away and then sand/polish the area to make a nice smooth transition, so smoothing out refers to the latter phase of the repair not the first part, should have been more specific.

BTW - I know two people that have had blade departures.. both ended with the engine departing the plane.

[Rowdy]

I've seen a whole prop come off! sheared right at the crank!

[GyvAir]

Better the whole prop departing than just a significant percentage of it!

[hotdog1]

IMG_0037 (2).JPG (398.31 KiB) Viewed 1627 times

prop failures scare me too, with this post, and this pic and one other that i have seen, that makes 3 prop failures that i know of and at least two that i have 'heard' of
i think they may be more common than we think