contrail

Was at Sheffield today, preflighting aircraft for return sector when heard loud bang.
Looked up & saw Schweizer 269 G-TAMA about 100feet away, on the apron, rocking violently from side to side with high RPM on rotors. Believe it was shortly to have gotten airborne. It came very close to toppling on its side. As Rotors slowed down, it became apparant all the blades were no longer evenly spaced and some major mechanical defect had occurred at rotor hub (guess thats what you call it....... i'm a fixed wing chap).
The fire services were in rapid attendance.
Anyone know anymore specifics?

nigelh

pound to a penny it was ground resonance . If you dont either cut the throttle as soon as it starts or take off ( this can end up in disaster as i know to my cost !!! A few weeks in hospital and a blade thru the cockpit ). This is usually caused by the oleo,s ( suspension on skids ) being low or uneven.

Whirlygig

A bit like this?

Cheers

Whirls

nigelh

yes a bit !! but in the 300 it can fully develop and rip itself to bits an awful lot quicker than that

Whirlygig

Yeah but G-TAMA is a 269D i.e. a 330 but point taken!!

Cheers

Whirls

md 600 driver

nigel

was it you that did it at sherburn years years ago whern the aircraft disintgrated

steve

A.Agincourt

Think you might find that the S333 suffered a MR head component failure and that any visible sign of GR was simply a secondary effect to that. The fire crew reported a loud bang heard above the engine during the run down period. That would seem to suggest something other than an undercarriage issue. However, rather than speculate, why not ring them and ask?

Best Wishes

Helinut

Good job it happened on the ground then

A.Agincourt

Ohhhhhh Yes indeed.

Best Wishes

nigelh

If it was a failure in the head then i would imagine the whole fleet would be grounded by now Ground Resonance is more likely the cause of the failure but if anything else you certainly wont be getting me into one of them !!
No , mine was a number of years ago amongst jumbos etc at Houston Intercontinental Airport . I was a passenger , my friend took off and then the blades started coming through the cockpit and we nosed straight in and it exploded . Got the photos but nothing left other than blades.... interesting part was the first fire tender was empty and i was on fire

A.Agincourt

nigelh: From what I have learned, the aircraft was in the 2 minute run down period following a ground run. If GR was the main issue then it would have occurred at an earlier point in time and not many minutes later sat at ground idle. Ground resonance doles not produce a loud 'bang'. Failure as a consequence of GR might do so but in this case it seems that the bang preceded anything else.

So in this event, you were in fact airborne? Then it could not have been GR eh? Or are you saying GR occurred on the ground and the pilot pulled away to get out of it and then there was a failure?

Best Wishes

nigelh

in my case the lift off was too late and the failure occured as we lifted i would guess. I still do not believe that a head will just fail on ground run without it being from ground resonance . The bang will have been the failure itself. As i said bfore it can all happen very quickly. That is why you should ALWAYS wear your seat belt doing ground runs as you can get thrown through thwe windshield into the blades ....which will ruin your day

Chopper Doc Junior

Ground resonance can also be caused by damper failure and have nothing to do with the condition of the oleos.

Whirlybird

Isn't G-TAMA a Schweizer 333?

A.Agincourt

Whirlybird: Yes it certainly is. According to SACUSA anyway.

http://www.sacusa.com/helicopters/333.asp


Best Wishes

Efirmovich

We are at it again ! It's amazing how some Ppruners can remotely diagnose the cause of crashes, what happened, why aircraft fail etc,etc with virtually NO facts,,,,,, !!!

May be the transmissoin siezed and all the blades broke off !!

The sound on my Sony telly keeps going off ??? any thoughts,, full fuel, frictions off, Hyd on and the wx is cavok

E.

nigelh

Efirmovich You are on the wrong site ....this site is for people to speculate on and even sometimes have a bit of fun . May i redirect you to the other site www.gogne.co.uk ( grumpy old git network )
As for your sony i can only imagine it is worn out from over use , maybe you should get out more
I still think head failure is unlikely . Does it have lead lag hinges like the 500 as i have heard of those breaking in flight. The blades will stay in line due to centrifugal forces but will move when rrpm drops . ( i think )

212man

So what causes head failures in the air then?

nigelh

212 i am not aware of any head failures in the air ....can you enlighten us ?
The only reason i go for G R is that it is the only thing that i know of that could effect any of these type of aircraft and will almost always result in head damage at least. One does ( if you are actually flying helis on a daily basis !!!) actually hope that structures like heads do not just fail for no reason

soggyboxers

nigelh,

There have been many examples of main rotor head component failures in flight. One very good friend was killed in the first S76 which suffered spindle failure and I knew the pilot of the S61 which suffered th same fate. Then there was the S76 in the Southern North Sea in which all died when a blade failed a few years ago, the Agusta 109 which mnaged an emergency landing as a result a component being installed upside down, the Wessex which lost a main rotor blade on final approach in Nigeria, the Bell 47 which lost a main rotor blade crop spraying in Canada in 1998, the Bell 214 ST which suffered a drag brace failure offshore Aberdeen (I forget the year), the R22 which landed with evere vibration due to a 3 inch crack in the main rotor blade root fitting in 2004, the S76B which lost a one metre section on the inboard portion of one main rotor blade in 2002....... need I go on?