EC120 Crash At Swansea Airport
Lets get serious here. Can anyone honestly believe that there is a company out there producing a helicopter with a known aerodynamical problem, after all the hassle from the last batch of incidences???
Is there an AAIB report imminent on this one (if no-one is hurt)?
If so, let's see what that comes up with, but I very much doubt whether that 'old chestnut' will be the cause.
Is there an AAIB report imminent on this one (if no-one is hurt)?
If so, let's see what that comes up with, but I very much doubt whether that 'old chestnut' will be the cause.
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Nr : "b) cos it was mentioned on Tuesday as being included soon in the PPL(H) syllabus (and, one hopes, the CPL syllabus)"
I think what the CAA said at the SHSS was that LTE has always been in the syllabus, but they are about to re-emphasise it. They pointed us all to AIC 70.00 and LASORS SS17.
LTE is about to be mentioned in the report about the 206 filming accident at Hadrian's Wall, May 30th. Having to go downwind to get the shot is no excuse.
Robinson do a specific session on LTE in their safety course - the military films are comedic, but the explanations are good.
As the CAA said to us, LTE is hardly mentioned in UK training books - but if you get the US books there's plenty on it.
I think what the CAA said at the SHSS was that LTE has always been in the syllabus, but they are about to re-emphasise it. They pointed us all to AIC 70.00 and LASORS SS17.
LTE is about to be mentioned in the report about the 206 filming accident at Hadrian's Wall, May 30th. Having to go downwind to get the shot is no excuse.
Robinson do a specific session on LTE in their safety course - the military films are comedic, but the explanations are good.
As the CAA said to us, LTE is hardly mentioned in UK training books - but if you get the US books there's plenty on it.
A quick search came up with this UK accident report which refers to the Boscombe Down report.
Someone I know who has lots of time on Gazelles says that in the military, the non-SAS aircraft never exhibited this phenomenon - anyone know different ?
TC:
The AAIB report may well be out in some months, but seeing as the accident happened on the 7th October, I think you're showing your optimistic side.
Someone I know who has lots of time on Gazelles says that in the military, the non-SAS aircraft never exhibited this phenomenon - anyone know different ?
TC:
The AAIB report may well be out in some months, but seeing as the accident happened on the 7th October, I think you're showing your optimistic side.
Last edited by The Nr Fairy; 21st Nov 2003 at 21:58.
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As the CAA said to us, LTE is hardly mentioned in UK training books - but if you get the US books there's plenty on it.
That is because of the relevent LTE experience which became a major safety discussion for OH-58 helicopter pilots particularly, and US military heli pilots in general back in the late 70's and early 80's. Fenestron Stall amounts to the same basic aerodynamic anti- torque profile.
Concerning this particular case, I doubt that an unresolved aerodynamic factor was the catalyst or main contributory cause to the destruction of the helicopter. What speaks volumes is the crash survivability design. Amazing that ther were no serious injuries or loss of life!
That is because of the relevent LTE experience which became a major safety discussion for OH-58 helicopter pilots particularly, and US military heli pilots in general back in the late 70's and early 80's. Fenestron Stall amounts to the same basic aerodynamic anti- torque profile.
Concerning this particular case, I doubt that an unresolved aerodynamic factor was the catalyst or main contributory cause to the destruction of the helicopter. What speaks volumes is the crash survivability design. Amazing that ther were no serious injuries or loss of life!
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Yes, EC120 has a forward CG issue....you cannot be in CG limits if loaded up and there is a mod around to correct this. Weight under the battery initially then weight in the end of the tail.
However, is LTE any different from any other aerodynamic problem that we learn about and deal with ie Vortex/Settling with Power, Ret Blade stall etc etc.
Sounds like 'LTE/Fenestron stall' = a cop out excuse for a handling error.
However, is LTE any different from any other aerodynamic problem that we learn about and deal with ie Vortex/Settling with Power, Ret Blade stall etc etc.
Sounds like 'LTE/Fenestron stall' = a cop out excuse for a handling error.
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Nr – The non SAS Ac are used extensively by the AAC and I have to admit we have crashed a fair few through tail rotor handling errors - the corrective actions for which, have been accurately described above. In the early days there were a few egotistical types who tried to baffle the rest of us with their wacky theories on ‘Fenestron stall’, I still remember standing in the hangar with about 20 other people while a certain prat waffled on about this and that and when he had finished, people started clapping! I couldn’t help thinking at the time; “This blokes talking b*ll*cks”. I got nice warm feeling a few weeks later when Boscombe Down stated that the so-called phenomena categorically did not exist.
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This is an excerpt from the AAIB Bulletin that Nr Fairy mentioned.
Gazelle yaw characteristics
In the majority of civil and military cases, loss of yaw control occurred in the hover or at low forward speed in light winds from the right. A few occurred in stronger winds or with wind from the left.
Both inexperienced and highly experienced pilots were involved in the military accidents and loss of control of pitch and roll during the subsequent high rates of rotation was a commonfeature. An 'optimised fenestron' was fitted to military Gazelles in the early 1980s as part of a weight upgrade programme.
The optimised fenestron had revised duct and hub fairings but did not appear to improve the incidence of sudden loss of yaw control.
The sudden loss of yaw control was attributed to 'fenestron stall'and, in response to concern, the Ministry of Defence (MOD) sponsoreda trial by the manufacturer, Eurocopter France, to investigate the phenomenum.
The trial took place in 1992/93 and demonstrated that, in conditions of low natural wind, a relatively small left pedal input of 5% (of total pedal travel) from the hover position can result in a yaw rate of 150°/sec being achieved in 10seconds.
It also showed that high yaw rates to the left (165°/sec)can be rapidly arrested by application of full right pedal without any tendency for aerodynamic stall of the fenestron.
The MOD advice included a statement that the extremely rapid build up of yaw rate in these circumstances was exacerbated if the SASwas not engaged.
The MOD trial did not establish why a small pedal input can result in the rapid build up of very high yaw rates. However, an earlier study, in 1991, by Westland Helicopters Limited had suggested that the trigger mechanism might involve a coupling of fenestron rotor induced swirl with the circulation contained in the main rotor tip vortices which may become aligned with the fenestron in certain flight conditions.
The study also suggested that considerationshould be given to changing the direction of rotation of the fenestron to become top-blade-aft which would probably solve the interactional aerodynamic problem.
Subsequent fenestron-equipped helicopters such as the SA365 Dauphin, EC135 and EC120 have top-blade-aft fenestron rotation; they are not known to suffer from sudden lossof yaw control.
In the majority of civil and military cases, loss of yaw control occurred in the hover or at low forward speed in light winds from the right. A few occurred in stronger winds or with wind from the left.
Both inexperienced and highly experienced pilots were involved in the military accidents and loss of control of pitch and roll during the subsequent high rates of rotation was a commonfeature. An 'optimised fenestron' was fitted to military Gazelles in the early 1980s as part of a weight upgrade programme.
The optimised fenestron had revised duct and hub fairings but did not appear to improve the incidence of sudden loss of yaw control.
The sudden loss of yaw control was attributed to 'fenestron stall'and, in response to concern, the Ministry of Defence (MOD) sponsoreda trial by the manufacturer, Eurocopter France, to investigate the phenomenum.
The trial took place in 1992/93 and demonstrated that, in conditions of low natural wind, a relatively small left pedal input of 5% (of total pedal travel) from the hover position can result in a yaw rate of 150°/sec being achieved in 10seconds.
It also showed that high yaw rates to the left (165°/sec)can be rapidly arrested by application of full right pedal without any tendency for aerodynamic stall of the fenestron.
The MOD advice included a statement that the extremely rapid build up of yaw rate in these circumstances was exacerbated if the SASwas not engaged.
The MOD trial did not establish why a small pedal input can result in the rapid build up of very high yaw rates. However, an earlier study, in 1991, by Westland Helicopters Limited had suggested that the trigger mechanism might involve a coupling of fenestron rotor induced swirl with the circulation contained in the main rotor tip vortices which may become aligned with the fenestron in certain flight conditions.
The study also suggested that considerationshould be given to changing the direction of rotation of the fenestron to become top-blade-aft which would probably solve the interactional aerodynamic problem.
Subsequent fenestron-equipped helicopters such as the SA365 Dauphin, EC135 and EC120 have top-blade-aft fenestron rotation; they are not known to suffer from sudden lossof yaw control.
