NZFF

Posted: **Tue Jul 07, 2009 9:47 am**

Here

The article doesn't mention the fact that the prop blade smashed into the cabin before it "left" the aeroplane finally.
I think this could cause a tragedy, however their attitude seems to be like: It's all good mate....

Posted: **Tue Jul 07, 2009 7:33 pm**

Well I have to admit, losing a prop blade is of huge concern. Because of the imbalance imposed if only one blade is lost, the engine can be torn from its mounts as well (this has actually happened in some cases). Propellers are not kept on strict maintenace regimes for nothing and have to given due care. Never underestimate the forces involved in a hunk of aluminium being flung around. Corrosion and cracks are of big concern. I worked a lot with Hercules and Orion propellers, which are a bit (lot) bigger and more complex as they also basically controlled engine speed. Flight engineers on Hercs and Orions always said, there was only two things that could kill them and they both started with P - Pilots and propellers !!

In this case a rear mounted propeller on a triple engine plane has failed and all is good. I'd hate to see the results on a twin or single.

Deane

Posted: **Tue Jul 07, 2009 10:05 pm**

so that is two trislanders that have had prop issues?? bit of a concern, i have heard stories of prop blades coming off and destorying the engine, wing and fuselage becasue of the centrifugal forces caused by the imballance. scary thought really, not much weight but moving at a fair speed, espically when imballanced!!

Posted: **Wed Jul 08, 2009 9:50 am**

Story 1

QUOTE

Passengers wouldn't have been too aware before the return that something was amiss," Mr Rea said. "They're quite a noisy aeroplane anyway - it's like a bus to the Great Barrier."[/quote]
and then we have this: Story 2

QUOTE

"It was like an explosion going off inside the plane," one told the Herald yesterday.

"The propeller came off and hit the side of the plane ...

"Both propeller blades came off - the whole thing just destroyed itself. It just completely self-destructed.

"A door got ripped off and the side of the plane got smashed in - we all got covered in glass.[/quote]
Not entirely sure where Mr Rea was getting his information from!!

Posted: Wed Jul 08, 2009 12:43 pm

by deaneb

jastheace wrote:
QUOTE (jastheace @ Jul 7 2009, 10:05 PM) <{POST_SNAPBACK}>
so that is two trislanders that have had prop issues?? bit of a concern, i have heard stories of prop blades coming off and destorying the engine, wing and fuselage becasue of the centrifugal forces caused by the imballance. scary thought really, not much weight but moving at a fair speed, espically when imballanced!!

Not sure what a trilander blade weighs, but Orion or Hercules blades are around 90kg each (yep there's a lot of alloy there). The props turn at a constant 1020 RPM. At that speed each blade exerts a 30 ton force on the prop hub !! Lose one (and it has happened) and you have an instant 30 ton force in the opposite direction. In the cases this has happened it has sheared the reduction gearbox from the engine, in half at the splitline and this complete with remaining prop departs company !! I also know a case of a Cessna 180 topdresser plane, which lost a blade in flight, followed by the engine (due to imbalance) the plane whent into an instant nose up attitued and several undescribed manouevres. The pilot managed to lower full flap and land in a paddock - now thats skill !

Posted: Wed Jul 08, 2009 1:43 pm

by greaneyr

HardCorePawn wrote:
QUOTE (HardCorePawn @ Jul 8 2009, 09:50 AM) <{POST_SNAPBACK}>
Story 1

and then we have this: Story 2

Not entirely sure where Mr Rea was getting his information from!!

The whole thing seems to be riddled with misinformation. I've heard suggestions it was the tail engine that lost the propeller, yet the image here:
http://www.nzherald.co.nz/nz/news/article....jectid=10583122
clearly shows the tail engine is fine but the starboard engine is not.

Posted: Wed Jul 08, 2009 3:20 pm

by jastheace

greaneyr wrote:
QUOTE (greaneyr @ Jul 13 2009, 02:43 AM) <{POST_SNAPBACK}>
The whole thing seems to be riddled with misinformation. I've heard suggestions it was the tail engine that lost the propeller, yet the image here:
http://www.nzherald.co.nz/nz/news/article....jectid=10583122
clearly shows the tail engine is fine but the starboard engine is not.

typical medai., never let the facts stand in the way of a good story. not sure on the props on the tris, but i remember watching an air crash investigation on the excat thing happeing. it was on an ASA emb 120, prop failed, caused imballance, and turbine riped itself of engine mounts, end result an aircraft with an engine hanging in very bad way, casued the crash of the aircraft, but pilots kept it in the air for alot longer than it should have, that was caused by the hollow props not being inspected properly, again not sure on the design of ga props.

i would think you would notice something like a prop falling off, the vibration allone would be quite violent, plus i would imagine the engine would sound that good either.

deaneb; you are always a fountain of knowledge, it is alot of force being put out when you think about it, 30tons is a little more than the lpg tanker i am driving

Posted: Wed Jul 08, 2009 5:19 pm

by ardypilot

Front page news in the Herald today- photos show the whole rear door was ripped off, and the blade hub and spinner completely ripped out!

NZFF

Prop smashes into plane @ Great Barrier