24th Feb 2016: EC 135 crash in northern germany
Hi all
http://www.bfu-web.de/DE/Publikation...ublicationFile
page 12 following - findings to the accident.
The pilot increased the distance to a groundtarget sideslipping with a groundspeed of about 30 knots when the helicopter slowly turned sideways and increased turnrate, when going through 90 degrees - resulting in four and a half turns, before crashing with a high rate of decend.
http://www.bfu-web.de/DE/Publikation...ublicationFile
page 12 following - findings to the accident.
The pilot increased the distance to a groundtarget sideslipping with a groundspeed of about 30 knots when the helicopter slowly turned sideways and increased turnrate, when going through 90 degrees - resulting in four and a half turns, before crashing with a high rate of decend.
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I don't know if the German federal Police does recurrent training in the simulator.
They do not fly a lot, too - 1100 hours in 7 years is not a lot for a professional pilot.
They do not fly a lot, too - 1100 hours in 7 years is not a lot for a professional pilot.
Hi all
http://www.bfu-web.de/DE/Publikation...ublicationFile
page 12 following - findings to the accident.
The pilot increased the distance to a groundtarget sideslipping with a groundspeed of about 30 knots when the helicopter slowly turned sideways and increased turnrate, when going through 90 degrees - resulting in four and a half turns, before crashing with a high rate of decend.
http://www.bfu-web.de/DE/Publikation...ublicationFile
page 12 following - findings to the accident.
The pilot increased the distance to a groundtarget sideslipping with a groundspeed of about 30 knots when the helicopter slowly turned sideways and increased turnrate, when going through 90 degrees - resulting in four and a half turns, before crashing with a high rate of decend.
The non-flying PIC apparently did not take over controls, neither did he call "left pedal". Rather he called "speed, speed, speed" (meaning "increase forward speed"), which as we all know is only the second or third response to uncommanded yaw (the primary response is to arrest the yaw with full, sustained opposite pedal, and - under certain circumstances - reduce power).
While it is a well-documented Fenestron issue that pilots do not apply enough, or quickly enough, or long enough, opposite pedal (but rather too little, too late), the pilot's response here of applying the *wrong* pedal is note-worthy.
The interim report implicitly links this wrong response to a German Police internal Safety Notice published a week before this accident (which was in force at the time of the accident and has since been corrected) which instructed to fly out of uncommanded right yaw by increasing forward speed and applying right (sic!) pedal.
The said Safety Notice was published after another police EC135 on 6 Feb 2016 encountered uncommanded right yaw. In that case the pilot was trying to transition from a high hover (1200' AGL) to forward flight by increasing power i.e. collective (as if transitioning in ground effect from a hover to forward flight) instead of simply applying FWD cyclic. Again, the helicopter behaved as expected with a torque reaction to the right.
However, instead of realising his/her mistake (of applying power instead of FWD cyclic) the pilot attributed the right yaw to the legendary "Fenestron stall" (which, as avid PPRUNE readers would conclude, doesn't exist). Hence the advise to reduce TR blade angle of attack by reducing TR power pedal (this in the EC 135 case that means less left rudder).
To rub this in: Not only did the pilot not realise his/her mistake at the moment when it happened in flight, but the incident was used to create the before-mentioned Safety Notice that established those unorthodox procedures to combat the legendary "Fenestron Stall".
The interim report implies that the actions or beliefs of both pilots of the occurrence helicopter (resulting in neither pilot taking corrective action to stop the yaw) were informed by this ill-fated Safety Notice that was circulated to all police pilots only a week before the accident.
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I’m a little confused by the BFU bulletin.
They note that they found the Fenestron drive shaft broken.
Then they summarise that: “The on-site examination found no evidence of any technical defect in the helicopter, either in the Fenestron drivetrain or any impediment to the controls.”
They go on to report that manufacturer test pilots reconstructing the accident flight were able to arrest a right yaw without difficulty, both with left pedal input and by reducing power and increasing forward air speed to fly out of it. That only seems relevant if the Fenestron was working.
Then at the back they reference the RFM emergency procedures for tail rotor drive failure. That only seems relevant if the Fenestron was not working.
So did the drive shaft break in flight, or as a result of the crash? If it remained intact in flight, what could cause the right yaw seen in the UMS data – starting slowly and increasing in speed until it seemingly became unrecoverable?
They note that they found the Fenestron drive shaft broken.
Then they summarise that: “The on-site examination found no evidence of any technical defect in the helicopter, either in the Fenestron drivetrain or any impediment to the controls.”
They go on to report that manufacturer test pilots reconstructing the accident flight were able to arrest a right yaw without difficulty, both with left pedal input and by reducing power and increasing forward air speed to fly out of it. That only seems relevant if the Fenestron was working.
Then at the back they reference the RFM emergency procedures for tail rotor drive failure. That only seems relevant if the Fenestron was not working.
So did the drive shaft break in flight, or as a result of the crash? If it remained intact in flight, what could cause the right yaw seen in the UMS data – starting slowly and increasing in speed until it seemingly became unrecoverable?
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@ATN
I'm talking about FNPT II (not the FFS), and I'm sure for EC135, but not sure about the 155 (I think it is there). Three years ago, they were finishing new trng facility at St. Augustin, talk was about FNPT's for all their types (135/155/332L1), but I don't know if they've finished everything yet.
JR
I'm talking about FNPT II (not the FFS), and I'm sure for EC135, but not sure about the 155 (I think it is there). Three years ago, they were finishing new trng facility at St. Augustin, talk was about FNPT's for all their types (135/155/332L1), but I don't know if they've finished everything yet.
JR
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Pilot flying with a total time of 377 hours, NVG Training just finished, ceiling of 600ft, operating under NVG at 400 ft at night, pilot non-flying with a total time of 1247 hours ...
Sorry to say but that doesn't sound like the right combo for that kind of mission.
Sorry to say but that doesn't sound like the right combo for that kind of mission.
