Printable View
It's a level down from a Mayday. If I was onboard I think a Mayday might have been more appropriate and a "Land as soon as Possible" just in case the same bloke fitted both props. I do fly in in helicopters so I guess losing a "prop" for us is very serious.Quote:
Originally Posted by kogvos
I note in the paper this morning the pilot reported an "uncalled for engine reaction" or something similar prior to losing the prop.
This led me to remember the doco on Beaufighters recently where the pilots would put the engine on full power if they saw oil pressure dropping and when it seized the prop would fly off and not create drag.
Leads me to wonder if the motor seized .
Regards Philip A
just a noob question,,
would losing a prop cause the engine to over rev?
I am only guessing, but perhaps the engine seized, then the prop sheared off!
My uncle who is 93 and still living, flew on Beaufighters (30 Squadron RAAF) during world war two and says if during combat they sustained damage to an engine, they would then try to flee the combat zone and head for the open sea, with the damaged engine running at full revs, so that once it seized the prop would shear off. They would then put the plain down in the open sea and be rescued by one of the Catalina's, that were normally skirting the battle zones for these situations. This happened to my uncle three times in his WW2 service.
I assume they didn't perform very well on one engine, they were known to be very "twitchy" on take off with two engines, due to the fact that the engines were very powerful, so maybe landing on a strip with only one corkscrew going was extremely difficult.
Cheers, Mick.
If the engine didn't seize, there should be separate overspeed protections built in for the propeller and engine itself.
The engine is a gas turbine so at the revs they spin they do not seize - they disintegrate with turbine blades going every where and fire and flame outs - that did not happen so more like a failure in the output end of the gearbox - as mentioned fatigue in the shaft is a likely option.
The other option is that it did loose one one blade and the immediate imbalance ripped the who lot out. I guess we have to wait and see.
Garry
As the RN would say, back in the day, all disasters came from the French.Quote:
Originally Posted by kogvos
Looks like the actual whole shaft has sheared inside the reduction box/ planetary assembly... very very lucky it didn't slice through the fuselage. They are a big bladed prop...😮
Sheared or just detached? - I don't know what holds the shaft in, but seeing it is normally 'pulling' it will have some sort of thrust bearing, possibly a tapered roller bearing, and if this fails, could it leave the thrust (pull) unsupported, or just supported by an alloy case - which would very rapidly wear away. This scenario could result from loss of oil in the reduction box.
Well according to the news, vibration started 25min out of Albury and at 18,000' - so the aircraft would have been near Tumut - the engine was shut down and descended to 8000'. If the engine is like most other turbo props with the prop feathered it should not be able to rotate but they did not say if could the fully feathered and locked.
The prop fell off over Camden some time after the engine was shut down. Questions are being asked why the aircraft did not divert to Canberra when the problem first arose - most likely would have arrived before the prop fell off.
It looks like the crack started sometime back and questions are being asked why this had not been picked up in routine maintenance.
I guess we now need to wait for the report. It is not clear at this stage whether the prop was turning or not when it fell off.
Garry