traicar,

These are different failure modes addressed in different ways. My suggestion would be that they continue to be so.

A tail rotor failure before a safety speed has been reached in a CAT A helicopter, in any type of departure, will (likely) result in a poor outcome.

A CAT A helicopter relies upon certification standards for avoidance of single-point-of-failure component accidents; yes the tail rotor and its drive system are weak points - that is why there are proposals to monitor their health.

These emergencies should be addressed as independent events. The probability of an engine failure is (about) 1:100,000 flight hours. The tail rotor should have a failure rate better than that. The evidence that I have seen appears to show that tail-rotor failures are a more common event on non-CAT A helicopters.

Jim

There was that Japanese 135 which had a tail-rotor-driveshaft/control failure IIRC.

The important bit I remember was that it was a 135 which had no Autopilot fitted and the bit in the tail which gets replaced with another bit which allows the Autopilot to control the Fenestron had failed. So as long as you have the Autopilot fitted to the aircraft that particular failure shouldn't happen.

Does that make sense?

And there was another one, which lost the T/R driveshaft somewhere near Manching airfield. It was a ECD testpilot, who encountered this experience in the early days of the 135 ( Problems with T/R driveshaft bearings ).
The japanese H/C had a broken fenestron pitch link due to a blocked bearing (?), after that, EC changed the design.
I know of at least two complete enginefailures ...

skadi

Do tell. Complete engine failures??

One was a engine-fuelpump driveshaft failure and the otherone also a mechanical failure in the engine gearbox, but I do not remember exactly what it was. Both engines stopped working, but no problem, cause the otherone did;)

skadi

So it wasn't both engines on the same aircraft decided to stop working at the same time.....

Thats correct! Two cases on two different H/C. With "complete" I meant total loss of that particular engine, not only loss of power or so. One was sudden failure without preceeding warnings right after passing TDP, the other one failed very short after ENG CHIP indication during cruiseflight.

skadi

@Skadi...

It was PT-6 or Turbomeca Arriel?

PT6 on a 135? Would be nice;) and powerful.

I do not remember very well, but i think, the fuelpump issue was on a T1 and the other one was a P2 ( PW 206 ).

skadi

P2 (PW206) :ok:

Eurocopter is obviously testing a new design for the oilcooler air inlets:

Helionline.de

skadi

Looks like a T2+ or e.

With the IBF fitted there is no longer any engine air going in the front of the cowling. The oil cooler exhaust is ducted up to the top rear of the upper cowling (gear cover) so it is not ingested into the engine from the normal outlet via the IBF. When the IBF is in bypass there is probably enough air available from the area of the mast and swashplate opening.

They may all end up looking like this in the future?

What I would like to know is how those particular flights finish after having lost an engine...I mean did the pilot scare himself or did he just take this bit of info in and land back on?

Isn't that where the aircraft will show it's mettle as in how it deals with problems? Or am I being naive......

tail rotor
 

p { margin-bottom: 0.08in; } Does anyone know about tail rotor failure events?
What about tail failure rate?

It seems only one or two.

How many flight hours has reached EC135 till now?

Both incidents were finished by a normal OEI landing and as far as i know without replacement of underwear;)

skadi

Glad to hear it all ended textbook.

Worldwide flighthours of the 135?

Well there are 1000+ 135s each with 2000hrs on average = a lot.

2,325,000 FH.

I/C

2.253.000 fh end 2011