Santa crash

[whatsarunway]

Anybody have any ideas on what happened the gassele caught on video that apeared on the news today , was everyone ok?

[Bill O'Average]

Just seen on sky news. Serbian Gazelle carrying Santa. Crew ok, Sky reports that santa died!

Looked pretty messy.

http://story.news.yahoo.com/news?tmpl=story&cid=573&ncid=757&e=6&u=/nm/20031230/od_nm/santa_dc Santa Crashes from the Sky

BELGRADE (Reuters) - A helicopter carrying a man dressed as Santa Claus to street celebrations in a Serbian town crashed on Tuesday, injuring several people.

The helicopter crashed a few hundred yards from a crowd of children gathered to greet Santa in the central town of Kragujevac, witnesses and local media said.

The pilot, co-pilot and the Santa were all injured, Beta news agency reported. Four people were injured but their lives were not in danger, a hospital official said. There was no word on the cause of the crash.

Serbs celebrate Orthodox Christmas on January 7 but children receive presents at New Year -- a legacy of communist rule when Christmas was not officially celebrated.

[Spaced]

Yeh I just saw the crash.
What a weird one. The helo seemed to be operating normally, as he got to 50-100ft AGL, he flared very agressively, almost 90deg pitch up. At that point the camera had lost site of it, and the veiw was switched to another camera.
The helo leveled out, the proceeded to spin about the mast, with an apparent lack of TR authority. THe helo descended pretty quick crashing into a tree before rolling onto its right side on the ground.
Good news all OK, Santa was walking around after :D .
If anyone else saw it would love to hear some opinions. The big flare to loss of TR authority has me confused.

[helmet fire]

Luckily, I have been able to watch this several times. Due only to the lack of responses, or anyone with knowledge on this one, I will have a GUESS:

Pilot is flying a Serbian Army Gazelle. He is delivering Santa for the Serbian Orthodox Christmas into an LZ in an urban area. As described above, all apears fine and beaut until the pilot attempts to fly between two buildings, at about 30 odd knots and maybe 100 ft. Just as he is about to dissappear behind the building from the camera's view , the aircraft enters a rapid pitch up manoeuvre and we lose sight of him. Very shortly after, he comes back into view heading back the way he came, and looking stable, but there are some small jerky movements. Suddenly, it looks as if control is lost, the aircraft begins spinning, rolling, and descending into the trees.

As the turn is left, it would suggest some sort of tailrotor issue, but there also appears to be some roll to the right (perhaps a reaction to the spin). The coning angle does not change sufficiently before impact to imagine that engine power has been completely lost, although things are happening quickly at this point.

I reckon he has gone to fly between the buildings, and seen a wire (hence the rapid pitch up), and then attempted to fly back out but had suffered a wire or object strike to the tail, and/or possibly the main rotor. Damage causes loss of control, and aircraft smacks in.

The tail rotor cannot be seen in the post crash footage, but there doesnt seem to be any obvious cables or similar around the main rotor head which is visible. The pitch change links do look damaged, but that maybe as a result of the 100 ft of pine trees they had to cut through to get to the ground. Both the pilot and the crewman are then filmed being attended to by medical personnel on the scene, and they dont look too critical initially, which is good.


Oh, and you can tell all your kiddies to relax. Santa walked away in need of a barber, a new set of shorts, and another reindeer team.:8

[Time Out]

There is also discussion on page 2 of this this thread (http://www.pprune.org/forums/showthread.php?threadid=111098) plus a link so you can download the video clip yourself.

[belly tank]

helmet fire,

I think you are on the right track, i viewed the footage last night and he seemed to be coming in quite hot through the buildings, seen the wire (possibly) and natural reaction is oops better stop now!! hence the quite rapid aft cyclic.

after his 180 deg turn he seemed to travel forward and a slight right yaw and then quite rapidly yaw left and decend into the tree's

i was talking to our other pilots today and after watching the video we agreed a wire strike may have been a factor.

what are the opinions out there from you guys?

[[email protected]]

I don't think the wire strike idea is valid - he descends instead of climbs which requires a major lowering of the lever when you pitch that much nose up. I wonder if he was looking so hard for the LS that he suddenly realised the buildings were there, scared himself avoiding them and then tried a very difficult repositioning manoeuvre resulting in settling with power/incipient vortex ring into the LS. Any control malfunction causing the pitch up would not have allowed him to recover it and any TR malfunction would have caused a much higher rate of yaw.
The only other possibility I can see would be if he inadvertantly (or santa did it for him) selected the hydraulics off - this makes the Gazelle much more interesting to fly, causes a pitch nose up in forward flight and makes the yaw control (especially applying right pedal) very difficult. The lever also tends towrds mid position (about 8 degrees) which would account for the descent in the flare.

[Lovre]

Hi Folks,

The photos from the crash site are here: http://www.boox.co.yu/images/20031230/index.htm

It was not the wire hit. In discusion with experienced ex. YAF heli-pilots they did not suggest any failure, but probably pilot's error during the landing between buildings, caused by windshare, downwash and low experience.

[helmet fire]

Interesting comments.

The cause of the rapid pitch up will be the key: did he pitch up because of hydraulic failure, hydraulic hardover, something catching on the cyclic, a wire between the building, suddenly realising he wont fit between the buildings, or what? There is no yaw associated with the initial pitch up, so I would discount tail rotor malfunction or pedal hardover at the initial stages.

A Hydraulic failure looks like it could be realistic, but a Gazelle pilot needs to look at the aircraft jerky movements, and yaw, following the return from behind the buildings. Is it realistic that he would have let the aircraft sink into the trees just because fo hydraulic failure? What are Gazelles like after a hydraulics failure? Would a cavitating pump cause pitch up and yaw fluctuations? Any Gazelle pilots out there? I do note that Lovre seems to have inside knowledge that there was no such failure, but Crab's idea about the "Santa Factor" is a good one.

I cannot see retreating blade stall having anything to do with this. Firstly, forward speed is absent and so is excessive conning angle suggesting low RRPM or over pitching, and secondly, there is little if any roll associated. Lastly, when he had completed the 180 and returned into view, the aircraft should have been controllable.

Crab: the LZ is not where the aircraft crashed. He still had some distance to fly, and examining the footage does not reveal the pilot searching for the LZ at all, rather he is looking steadily forward and appears to be flying where he intended to be. Also, at the low airspeed, I am not convinved that there would have been too much cyclic climb resulting from the pitch up, hence no subsequent need to rapidly lower the collective, so I cannot see Vortex Ring State (even in it's incipient stages) in this one either. The aircraft re emerges from between the buildings without any descent, and little evidence of large conning angles suggestive of pulling max power against any downdraughts. I see your reasoning on trying to hover with insufficient power, but again, the conning angles just dont look too excessive - does the Gazelle bleed off quickly? Could he have suffered fenestron stall whilst trying to hover when he re emerges from the buildings?

As for the downdraughts, or turbulence, that may very well explain the pitch up, but why the subsequent crash? The footage I have seen shows the LZ, and there does not appear to be any excessive winds around the vicinity, including during any of the postcrash footage.

As for engine popping, that is a possibility but the popping noises were present before the aircraft arrives, and continue at the same intensity even though the aircraft goes out of sight between the buildings suggesting these were not related to the aircraft. Lastly on this one, wouldn’t the yaw have been in the opposite direction?

Regardless of why the aircraft pitched up, it appears that there is some sort of loss of control issue after that manoeuvre, and this must be control integrity related either due to failure, insufficient power/fenestron authority, or object strike – so my guess is the ultimate cause will be whatever caused the pitch up.

[[email protected]]

Helmet Fire - With over 1000 hours on type I think I might qualify as a Gazelle pilot which is why I mentioned its handling qualities with the hydraulics off. The amount of pitch nose up on the video must be the result of an aft cyclic input – and that amount of nose up would make a Gazelle climb quite quickly. The lever must therefore have been lowered to compensate as the Gaz clearly pitches nose up and descends.
The highest aerodynamic backloads occur on the retreating side of the disc (starboard side on Gazelle) aft of the abeam point (which is why a helo pitches up and rolls when RBS is encountered). If the hydraulics are deselected the cyclic moves back and right, the lever tends towards mid position (8 degrees) which is downwards for most cruise configurations and the pedals become extremely heavy with a lot of force required to apply the appropriate amount of right pedal. In the hover the aircraft is quite a handful and overcontrolling is easy to achieve (you still have a very responsive helicopter but the amount of force required to operate the controls means that precise movement is extremely difficult).
If the hyds were switched off inadvertently then the sort of manoeuvres seen on the video are exactly what one might expect – pitch nose up and descent followed by a very wobbly hover with a strong tendency to yaw left and descend. The less experience on type the more likely the pilot is to embarrass himself especially if he hasn’t practised hyd out landings for a while.