Haven't you guys got email? Getting back to the thread...

Although extreme mast bumping might explain the MR separating from the aircraft (indeed, if this happened - it's almost impossible to tell from that one grainy photo), it doesn't explain the 'lots of smoke'. Given the topology and weather, I'd be very surprised if mast bumping had anything to do with it.

- my first comment. I don't know him but for the grace of god (or whoever) it could be me...

So sorry for a little thread drifting - albeit related to R22 safety. A change from the speculation based on news reports and untrained witnesses maybe?

Yes I have email and I am sure stingfellow does too - however without connecting through the thread it is unlikely we would find out each others.

He is doing and I have done the course that may save our lives flying the Robinson machines - mutual ground between pilots - the same mutual thing that may one day kill us too. I am sorry a comment about that course offends you so much. Maybe discussing the fatal accidents shown, poor training, training accidents would be more appropriate?

I rarely fly the Robinson these days but learnt on them and personally think the subsided course is well worth the money and if it brings pilots closer together to discuss avoidable accidents then it has to be good.

HTC

i should have asked before how old was the machine and was it still matched up on components?

re this;
I don't think that was needed,
The gentleman had been check and training on banderante I believe, a definite plus for instilling in his mind a process to think through all considerations for emergencies - always. He has also just had the exposure of new training, not as if he had been sitting around for years and decided to go for a fly. It would be a very strange instructor that didn't show him the pitfalls of high time F/W vs low time R/W.

cheers tet

tet
G-CHZN was a 1988 a/c originally reg as G-GHZM. I purchased the a/c in early 1999 immediately after a 1st Robinson overhaul and re-registered it as G-CHZN. PDG (Wolverhampton) carried out a second overhaul for me in 2007 after which I sold it.

For me it is a sad end to the a/c which was the basis of my flying and my thoughts go out to the pilot's family as for all of us there is an element lurking in the corner of our minds that says ' there but for the grace of god .....'

Stringfellow - he wouldn't be the first FW pilot to react incorrectly to an engine malfunction in a helicopter - the old adage of 'when under pressure you revert to what you were first taught' may be applicable here. FW pilots when faced with an engine fail in the cruise will inevitably push forward to retain speed rather than flare. If you combine this with an adrenaline fuelled lowering of the lever because you know the rotor inertia is poor, you can quickly generate a low G environment which we know is a bad thing for Robbies.

Just supposition of course.

More supposition - pushing cyclic forward abruptly to avoid a bird strike?

IF it was MB:
FW jocks wouldn't do anything at all if a donk stopped in their multi engined a/c, the autopilot would trim and slow automatically:).
He might have reacted this way and just did nothing.
In a helo (single and twin), instinctively a rotary pilot would lower the lever to contain Nr (we would all agree on that little baby!) and in so doing, the a/c would pitch down automatically due to the impingeing air from below on the stabilisers. Most helo pilots end up having to contain the amount of nose down that occurs for this very reason.
So, mast bumping/tail cone contact could easily occur during this nose down episode and/or by overcorrecting the pitch down by too much aft cyclic.
He may have reacted this way.

In a Robbie - an uninitiated FW pilot would have his work cut out.

I have bugger all in F/W, only singles and less than 3K. Their cruise speed is usually a fair bit more than best range glide speed. What I was taught was to pull up for more height if possible. I discarded that later and simply adopted a technique off bleeding off airspeed until the best range speed appeared and trimmed it at that attitude. I figured much less energy waste, whether I was turning to a spot or not. Don't forget this gentleman was a F/W instructor.

Re the bird evasion that is possible I suppose, but i personally think it very unlikely that he would have suffered a serious mast bump by simply pushing forward on the cyclic even with down collective.
Don't forget serious mast bumps are often coupled to blades going way out of whack and severing the tail boom and or the cabin, which did not happen.

The smoke was not a fuel fire or it would have been burning on the ground.

Oil could have been ingested from a ruptured xmon through the cooling fan and blown over the exhaust, mucho smoke! Or spilt on the exhaust from an engine rupture. Or it could come from the belts. These new belts don't seem to smoke before failure, they just break as far as I know.
The old belts will smoke but not for long before failure, say a few seconds, i think it unlikely to be seen from the ground, just a hunch.

I can't presume he didn't lower the lever after a simple belt or engine failure because the aricraft is inverted. In a rotor blade stall they nearly always land right way up with the blades acting a bit like a wind vane after they bend.

Also quite often before they bend properly they will strike the boom or the cabin.

I guess if the blades were the old variety and a few hundred hours old it is reason enough to suspect a delam causing a blade breakage, which fits nicely with a bang when it breaks and bits seen falling elsewhere, but once again why the smoke. Maybe that could have ruptured the xmon?

The blade delams on the R22 that I know about haven't failed because of it and make a very loud swishing noise which is absolutely unmistakeable, no comment about that either.

But then again I could be way out of whack with all of this.
I would dearly like to see a photograph from the other side.

Collective Response
 

Quote:

---

Originally Posted by Stringfellow # 39

"he of the old 2.4 second throttle roll off with no collective response... "

---

Was there any cyclic flare to encourage RRPM during the initiation of the simulated engine failure, in the absence of lowering the collective?

i dont know but i will ask the question for you!! i suspect not, it was at 100kts so i guess the deceleration of the ac would have helped a bit. im told the 2.4 sec was electronically measured,,, testing is testing but it sounds a needless risk to me.

PM
 

OK Stringfellow.

I will PM because I feel my comments are off-topic, especially in the very sad circumstances that generated this thread.

I wish to apologise to members for my lack of sensitivity.

TC

You've brought the pedant out in me.

You wrote 'the a/c would pitch down automatically due to the impingeing air from below on the stabilisers. Most helo pilots end up having to contain the amount of nose down that occurs for this very reason.'

The nose down pitch of a helicopter in cruise flight as a secondary effect of lowering the collective (or the nose up pitch from raising the lever) is due to 'V squared' effects of advancing v retreating blade and subsequent phase lag acting 90 degrees later. It's got nothing to do with the upwash/downwash on the horizontal stab - have you seen the size of the R22 stab? This can be seen in flight as the pitch up/down is instantaneous, long before any RoD flow has had chance to develop.

Back to the topic..........

JJ

Jellycopter, you beat me to it - it's just flapback/flap forward. I'll nip upstairs to the Sim and give him a clip round the ear!!:)

Crab

Yes, I've got my pedantic hat on today. Get TC to give you a clip round the ear whilst your at it!;)

We normally consider Flapback (forward) to be a result of changing airspeed.

Pitch up / down in the cruise, as a secondary effect of collective, is a result of V squared and does not require a change in airspeed. With collective input, the pitch (CL) on advancing and retreating blade is changed by the same amount but the V Squared is hugely different resulting in significantly different amount of lift change on advancing and retreating sides of the disc. This causes the blades to flap and the effect is felt 'approx' 90 degrees later, hence the pitch up/down of the aircraft.

Similar to flapback, but not quite the same.

JJ

cyclic thanks for the message but if anyone else is interested i asked chief pilot tim tucker about the 2.4 sec lag. it was a test flight at vne plus 10% when he closed throttle. he did not flare the ac to maintain rpm but he held attitude with gentle aft cyclic, and coupled with the deceleration from vne plus 10% would clearly have helped.

and back on topic today in the auto rotation section he mentioned what happens if you jam in left pedal by mistake at entry. now i may miss some bits or get it wrong, im only a fresh faced newbie, but as left goes in ac rolls left out of trim. relative airflow (plus stalling blades too??) creates a right rolling movement that inverts the aircraft.. and this poor chap in ely landed upside down it appears???

Mast Bumping Article
 

PM to Stringfellow very rewarding. "Fresh Faced Newbie also" and would like to contribute this link. Please click link and scroll down to the relevant information.
NEGATIVE G AND MAST BUMPING | Becker Helicopters
Stay safe out there.

Stringfellow,
It is a possibility and the two that I know of were violent rolls right over. Each time there was an instructor on board who was able to power up and land. I just missed seeing one such event by about ten seconds. I don't know what their recovery technique was and I feel that the one I saw had forgotten by the time he landed, for which I don't blame him at all.

In that case the engine oil blew out all over the place and was all over the tail boom when it landed.

Certainly one must keep an open mind. As a previous F/W instructor he would have known that he had to act in some way and had he not been taught the procedure of entering auto from a sudden engine failure then he could react incorrectly as others have.
His flight training Records might be a good place to start.

Of course there is other stuff to promote the theory. No fire on impact, which if there was any large quantity of fuel on board with that sort of impact is very likely to burn, meaning he may have experienced fuel starvation for a variety of reasons to stop his engine.

The smoke can be explained by oil being blown out of the engine only if it was running.
Perhaps if they were the new type of belts and they broke it “might?” be heard from the ground.
Had the belts broken suddenly and being inexperienced in R/W he may have been confused by the noise of the engine over revving but delivering no power, and to recover from an inverted position without power and the RRPM decaying badly might well be difficult, I don’t think anyone would know.

I think it easy to believe that a roll inverted with no power applied immediately would show as a blade strike on the aircraft somewhere, unless he then did suffer a severe mast bump which allowed the head and blades to fall seperately.

A sad conundrum for sure
tet

relative g
 

absolute/relative minefield - ( also relevant to pressures - 500hPa is not negative pressure - just LOW pressure - )

... between 0g and 1g is LOW g

... at 0.9g it is not so low that you'd bother calling it LOW

... less that 0g (eg -0.5g) is NEGATIVE g (and LOW g)

Jellycopter - pedantically, flapback is considered under the umbrella of flapping to equality (like inflow roll) and in this case the effect of raising the lever creates an inequality of lift across the disc because of the difference in V squared such that the disc flaps back - exactly the same result as when increasing speed - hence my use of the term. Just because CFS doesn't call it flapback doesn't mean it isn't - they probably would if it was in AP3456. ETPS deals with both in the same paragraphs in their notes. Don't forget, some of us were teaching this stuff before you completed your pilots course;)

ISTR that the correct term for this is something like 'pitch instability due to collective application'.

JJ: sadly you are quite right. [I salute you!].
In mitigation I was trying to steer clear of the AP series of explanations so as to keep the conversation 'light', now you have sent most spectators off to sleep. Secondly, I was actually thinking 'gazelle theory' when I was writing it, where airflow on the underside of the 'stab' does have quite a noticeable effect all be it secondary.. Thirdly, it all seems so long ago...............
Crab: you fell for that old chestnut re: Flapback...tut, tut.:D