Apache Tail Rotor Failure
I should have added that small singles tend to have relatively small fins or stabilisers and skinny tail booms so there is very little surface area to provide anti-torque thrust.
Compare that to something like a an AS365 with a massive fin, vertical stabilisers and a thick tail boom.
Nigel - exactly my point - a neutral pedal position doesn't mean zero TR thrust.
Compare that to something like a an AS365 with a massive fin, vertical stabilisers and a thick tail boom.
Nigel - exactly my point - a neutral pedal position doesn't mean zero TR thrust.
Originally Posted by [email protected]
Lonewolf50 - apparently the cause was an incorrectly torqued anti-flail mount on the TR drive shaft that came loose, slid down to the next TR bearing mount and jammed against it then gradually sliced its way through the TR driveshaft itself.
Hadn't realized how robust the spec was on Apache.
even in an Apache with undercarriage and stroking seats designed to absorb over 25 G of vertical impact.
even in an Apache with undercarriage and stroking seats designed to absorb over 25 G of vertical impact.
http://citeseerx.ist.psu.edu/viewdoc...0.1.1.214.8052
A bit like doing an EOL in a Lynx and just not bothering to cushion the touchdown at the bottom.
Crab - good point re auto characteristics of medium to heavy twins vs light singles.
No idea about the AH64 but s/e AH1s and Hueys of course auto like butterflies! (as do 212s)
No idea about the AH64 but s/e AH1s and Hueys of course auto like butterflies! (as do 212s)
Hughes - I think it varies from type to type, The 212 is an EOL for a full drive failure whereas a 365 (massive fin) is a fast running landing.
The Lynx and Sea King were EOLs if you couldn't get a sensible speed for running landing.
The problem with the EOL in a bigger helo is trying to get to zero groundspeed - or you risk landing with forward speed but not straight in which case you could roll over.
There is certainly no magic bullet solution and I think we all fervently hope we are not put in the position of having to try.
Back in the 90's a Wessex had a TR drive shaft failure in North Wales - some colleagues of mine were involved - the failure happened at 60 kts and despite lowering the lever and pushing the nose down, they were unable to regain forward controlled flight and were faced with chopping the throttles in a spinning helicopter descending over a lake.
The Lynx and Sea King were EOLs if you couldn't get a sensible speed for running landing.
The problem with the EOL in a bigger helo is trying to get to zero groundspeed - or you risk landing with forward speed but not straight in which case you could roll over.
There is certainly no magic bullet solution and I think we all fervently hope we are not put in the position of having to try.
Back in the 90's a Wessex had a TR drive shaft failure in North Wales - some colleagues of mine were involved - the failure happened at 60 kts and despite lowering the lever and pushing the nose down, they were unable to regain forward controlled flight and were faced with chopping the throttles in a spinning helicopter descending over a lake.
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TR Drive Failure
Hello all,
I was Nick's SQHI prior to this deployment on Herrick (I was in the process of leaving the mob at the time) so maybe I can shed some light on how TR drive failures are taught on the UK Apache fleet. It was most definitely a TR drive shaft failure (it severed mid way up the tail boom) - the TADS footage of the aircraft in flight from his wing is quite eerie with the tail rotor stationary!
In the simulator a TR drive shaft failure is given after setting up at a suitable height for autorotation with an airfield ahead - as soon as TR drive is lost the EPLs (engine power levers = throttles) are retarded to idle and the HP enters autorotation. In order to maximise the effect of the tail fin the teaching is to maintain a high run on speed. This is, of course, an ideal.
The terrain in and around the Helmand River is rough, dusty and full of wadis and other hazards. Plainly a high speed run on isn't an option!
I've flown multiple aircraft types in the AAC and I must say that one of the strengths of the training was instilling in aircrew the idea that there are many ways to achieve the same result whether that be gunnery, sensors or indeed emergencies. The FRCs tell you what you should do but, as was the case here, Nick's previous experience in Helmand and in the simulator led him and Charlie down a different path. I have to say that they handled it very well indeed and to do a low level (400ft agl) double engine off into a dusty, uneven desert environment from the front seat with minimal recent "hands on" was an exceptional feat!
To give those of you that fly smaller, lighter helicopters a flavour of performance in Afghanistan typical AUM on lift from Camp Bastion was around 19,000lbs including RCEFs (jettisonable external fuel tanks), stores booms carrying HF missiles and rockets, and around 550 rounds of 30mm carried internally in the magazine.
And the ruggedness and crashworthiness of AH is pretty awesome!
I was Nick's SQHI prior to this deployment on Herrick (I was in the process of leaving the mob at the time) so maybe I can shed some light on how TR drive failures are taught on the UK Apache fleet. It was most definitely a TR drive shaft failure (it severed mid way up the tail boom) - the TADS footage of the aircraft in flight from his wing is quite eerie with the tail rotor stationary!
In the simulator a TR drive shaft failure is given after setting up at a suitable height for autorotation with an airfield ahead - as soon as TR drive is lost the EPLs (engine power levers = throttles) are retarded to idle and the HP enters autorotation. In order to maximise the effect of the tail fin the teaching is to maintain a high run on speed. This is, of course, an ideal.
The terrain in and around the Helmand River is rough, dusty and full of wadis and other hazards. Plainly a high speed run on isn't an option!
I've flown multiple aircraft types in the AAC and I must say that one of the strengths of the training was instilling in aircrew the idea that there are many ways to achieve the same result whether that be gunnery, sensors or indeed emergencies. The FRCs tell you what you should do but, as was the case here, Nick's previous experience in Helmand and in the simulator led him and Charlie down a different path. I have to say that they handled it very well indeed and to do a low level (400ft agl) double engine off into a dusty, uneven desert environment from the front seat with minimal recent "hands on" was an exceptional feat!
To give those of you that fly smaller, lighter helicopters a flavour of performance in Afghanistan typical AUM on lift from Camp Bastion was around 19,000lbs including RCEFs (jettisonable external fuel tanks), stores booms carrying HF missiles and rockets, and around 550 rounds of 30mm carried internally in the magazine.
And the ruggedness and crashworthiness of AH is pretty awesome!
Last edited by The Cryptkeeper; 9th Jun 2016 at 13:58.
Don't have any of the old manuals so take my recall with a grain of salt.
For those who may care to `search`,`Tail-rotor failure...have you had one....? `may provide some more info on t/r failures,that guys have had.Threads from about 2010 but still relevant.
The real `biggie` is a loss of tail rotor and gearbox,and the change in Cof G,to somewhere well in front of your feet....!
The real `biggie` is a loss of tail rotor and gearbox,and the change in Cof G,to somewhere well in front of your feet....!
My former Chief Pilot had a TR drive failure in a Twin Squirrel many years ago. He managed together in back to the airfield and make a run on landing.
https://m.youtube.com/watch?v=z3oVw6_0MEU
https://m.youtube.com/watch?v=z3oVw6_0MEU
