Police MD 902 Crash at Hannover Airport
Flaxton
To that Japanese incident you quote you can add at least one in the USA as 'confirmed' by the authorities ...
According to the US NTSB the 16 October 2003 loss of MD 900, registration: N179PA was 'the pilot's in-flight loss of control due to the fatigue fracture and separation of the force limiting control rod (an integral part of the anti-torque system), which resulted in the helicopter's uncommanded yaw/spin and subsequent collision with terrain.' I am not sure whether that is the same rod as the recent Austrian 'allegation'
High run-on speeds are not that unusual. The 1984 accident to Bell 222 G-METB at Hatfield was as a result of t/r failure and that required a fast run on [wheels not skids] that was finally to end up with the machjine on its side as balance was lost. I have the report here somewhere .... but I recall the approach speed was significantls over 90kts.... 120kts was mentioned...
To that Japanese incident you quote you can add at least one in the USA as 'confirmed' by the authorities ...
According to the US NTSB the 16 October 2003 loss of MD 900, registration: N179PA was 'the pilot's in-flight loss of control due to the fatigue fracture and separation of the force limiting control rod (an integral part of the anti-torque system), which resulted in the helicopter's uncommanded yaw/spin and subsequent collision with terrain.' I am not sure whether that is the same rod as the recent Austrian 'allegation'
High run-on speeds are not that unusual. The 1984 accident to Bell 222 G-METB at Hatfield was as a result of t/r failure and that required a fast run on [wheels not skids] that was finally to end up with the machjine on its side as balance was lost. I have the report here somewhere .... but I recall the approach speed was significantls over 90kts.... 120kts was mentioned...
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Flaxton
I should have made clear that I did not question the goarounds and I'm perfectly aware that the helicopter will not have an instantaneous combustion
in midair just because the anti torque system (however that might look like) failed - or at least isn't working properly anymore.
I heard of guys (or girls) who attempted up to 10 run-on landings before making it successfully - why not if you have enough fuel?!
Like sulley said, 90 kts was most definately not the run-on speed - I used the "
" to indicate that I think a reporter heard a number and thought he could educate the general public how dangerous the maneuver was - and that only becomes clear if you read between the lines. 
...I recall that Nick said on this forum that the notar has 3 times the parts of a conventional T/R system... its nice to remove the tailrotor strike problem (among other advantages), but you still have multiple single point of failures!
Phil
I should have made clear that I did not question the goarounds and I'm perfectly aware that the helicopter will not have an instantaneous combustion
in midair just because the anti torque system (however that might look like) failed - or at least isn't working properly anymore.I heard of guys (or girls) who attempted up to 10 run-on landings before making it successfully - why not if you have enough fuel?!
Like sulley said, 90 kts was most definately not the run-on speed - I used the "
" to indicate that I think a reporter heard a number and thought he could educate the general public how dangerous the maneuver was - and that only becomes clear if you read between the lines. ...I recall that Nick said on this forum that the notar has 3 times the parts of a conventional T/R system... its nice to remove the tailrotor strike problem (among other advantages), but you still have multiple single point of failures!
Phil
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PANews
I think it was as a result of that incident that a mod was introduced to attach a couple of retaining lanyards to the rod to stop this happening again. It was in the form of an SB with the lanyards being inspected on the Daily "A" check.
It may be that the Austrian machine had a similar problem but I think we would probably have known by now if that was the case.
Phil - wasn't meaning to comment on your interpretation of the report, just a general comment of the ins-and-outs of handling a NOTAR failure. No offence intended!
I think it was as a result of that incident that a mod was introduced to attach a couple of retaining lanyards to the rod to stop this happening again. It was in the form of an SB with the lanyards being inspected on the Daily "A" check.
It may be that the Austrian machine had a similar problem but I think we would probably have known by now if that was the case.
Phil - wasn't meaning to comment on your interpretation of the report, just a general comment of the ins-and-outs of handling a NOTAR failure. No offence intended!
Would any of our European colleagues like to pass on any more details about this accident?
If not publicly then by p.m. as I am very interested in what the failure was and what the crew did to try and resolve it.
If not publicly then by p.m. as I am very interested in what the failure was and what the crew did to try and resolve it.
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I see MD have now issued SB106 to be complied within 10 flight hours. perhaps this means a busy weekend for PAS etc.
Anonymouse it might have been a wasted 1 1/2 hours flying after all.....let the dog wag the tail in future.
Anonymouse it might have been a wasted 1 1/2 hours flying after all.....let the dog wag the tail in future.
According to the german accident investigation board the police helicopter crashed after a mechanical failure of the NOTAR control. The air outled blocked in a very "unfavorable" angle and prevented a safe running landing. Crew and maintenance have done everything correct.
Under suspicion and not secured by the accident board is now the lengthened tail boom assuming a higher stress factor with this extension could be the failure reason.
Liability for MD in this case is not out of question according to news reports.
The accident board do not exclude a link to the austrian accident 14 days before, also a secured NOTAR control failure.
Under suspicion and not secured by the accident board is now the lengthened tail boom assuming a higher stress factor with this extension could be the failure reason.
Liability for MD in this case is not out of question according to news reports.
The accident board do not exclude a link to the austrian accident 14 days before, also a secured NOTAR control failure.
Last edited by tecpilot; 25th Dec 2007 at 09:00.
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Fixed Thruster
Tecpilot,
Can you expand on "very unfavorable angle"? It sounds like you mean open to the right, but do they know how much right, and what kind of maneuvering was being done when it became fixed to the right?
Mark
Can you expand on "very unfavorable angle"? It sounds like you mean open to the right, but do they know how much right, and what kind of maneuvering was being done when it became fixed to the right?
Mark
"Very unfavorable angle" is the term used official by the accident board. The file is not closed and still under investigations. Itīs a federal a/c, no insurance cover, several millions damage. The accident board will give limited infos until they have found a solution with MD i believe.
Interesting to see they have got suddenly a new helicopter within that very short time from the US. Itīs the fastest replace i have ever seen on a public operator.
Interesting to see they have got suddenly a new helicopter within that very short time from the US. Itīs the fastest replace i have ever seen on a public operator.
Thread Starter
First Report
The first official report about this accident was released some days ago:
http://www.bfu-web.de/cln_009/nn_415...tin2007-11.pdf
Page 17-19, including some pics from the relevant broken parts.
skadi
http://www.bfu-web.de/cln_009/nn_415...tin2007-11.pdf
Page 17-19, including some pics from the relevant broken parts.
skadi
Thread Starter
These first reports ( bulletins ) are only available in german, only the final investigation reports are publisehed in german and english.
skadi
skadi
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mod
I cant read the German either but does that look like a control rod failed under torsion?... is that part of the new thrust mod mentioned above.... did it shear before or after crash is the question....?
Could it be that one broken fixing = 7 million Euros? Plus the previous 902 with the mod......? ouch
Could it be that one broken fixing = 7 million Euros? Plus the previous 902 with the mod......? ouch
Thread Starter
According to the report, the link between the control cable and the push-pull-tube ( red circle in the pic of another MD ) broke obviously before the accident, resulting in loss of anti-torque-control below 80 kts. The push-pull-tube was replaced with the tail-extension.
skadi
skadi
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"Obvious"
I don't think there is any "obvious" about it. Only forensic tests will determine what caused the break. The break could be the result of:
Heavy control input to attempt to free a possible restriction, or
catastrophic failure during the crash itself, or
fatigue due to unknown stresses.
There may be other possibilities but until the result of investigation is published, we will not know what is the cause of the break or of the crash itself. IMHO of course.
Heavy control input to attempt to free a possible restriction, or
catastrophic failure during the crash itself, or
fatigue due to unknown stresses.
There may be other possibilities but until the result of investigation is published, we will not know what is the cause of the break or of the crash itself. IMHO of course.
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Translation
Mouse,
Find the German original, highlight same, cut and paste into Google language tools and use the 'translate' section, selecting German to English of course!
Please bear in mind that it is a very literal translation.
Eagle
Find the German original, highlight same, cut and paste into Google language tools and use the 'translate' section, selecting German to English of course!
Please bear in mind that it is a very literal translation.
Eagle
On 21 July 2008 Calstar the EMS operator reported that Explorer N902CS suffered an emergency landing after the pilot reported lost of tail authority whilst landing at their base in Salinas, California. No injuries were reported.
The pilot executed a 'hovering autorotation' resulting in damage to the skid crosstubes.
The loss of anti-torque control was caused by the failure of the thruster cone control rod. CALSTAR have grounded their fleet pending an inspection of the control rods.
The pilot executed a 'hovering autorotation' resulting in damage to the skid crosstubes.
The loss of anti-torque control was caused by the failure of the thruster cone control rod. CALSTAR have grounded their fleet pending an inspection of the control rods.