UK AAIB November 2016

[John R81]

Sud Aviation SA342J Gazelle, YU-HET - More interesting from the viewpoint of control of Serbian maintenance. Helicopter damaged beyond economic repair.


Robinson R44 Astro, G-BZGO - Bird strike at 1500ft / 90knt. Came through the canopy close to the nose / landing lights. Most likely a Herring Gull. Landed safe.


Robinson R44 Raven, G-EVEE - Ran out of fuel, autorotation got them down with damaged skids

[HowlingMad Murdock]

UK AAIB

Many thanks for posting John R81 - interesting and instructive reading.

[[email protected]]

Ref the Raven running out of fuel - it is important to understand that spirited manoeuvring with low fuel states in most aircraft can interrupt the flow to the engine. He hadn't actually run out of fuel but 25 degrees AoB was too much for the low fuel state he was at.

[haihio]

Very interesting and constructive reading, thanks for posting

[John R81]

Limit for my 120 is 15 degrees, according to the POH. Never tried it in practice. Only once have I seen the "Low Fuel" caption light-up; when I deliberately sat in the hover over the pad until it came on (just to check for myself that it was working properly, as the machine was just released to service from maintenance on the fuel tank. Added 40kg of fuel and hovered until the fuel meter read 30, at which point the warning light came on).


The R44 POH recommends landing if the low fuel light comes on, but no mention of manoeuvring limits. Even Safety Notice SN-15 (in section 10) only warns not to let the fuel quantity reduce in-flight to the extent that the "Low Fuel" caption illuminates.

[Frying Pan]

Disagree. I've often flown an R44 with 3 other people and the fuel definitely lasts more than an hour, sometimes 3! As for luggage, it's a helicopter for God's sake. It won't be used for camping.....often!

[Two's in]

It demonstrates far more professionalism to be an expert on your aircraft's range and endurance, rather than having to become an expert on Engine Off Landings.

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The Gazelle getting airborne seems straightforward - if you switch off the hydraulics, the lever tends toward mid-position (you have to push it down to get it to land). So if the engineer hasn't really put enough friction on then it isn't a surprise that it jumps up when the hyd pressure is removed. The 180 turn is because the pedal forces are very high without hyds and if you don't have a strong right leg ready to brace, you will yaw very quickly.

[Hughes500]

Two

Only problem with that as I have seen people take it right to the nth degree running fuel right down to just before low fuel light. That is great but you are relying on your calculation, do you really know how much fuel is in the tank and a gauge that quite frankly should be in Noddy's car. Much better to be a better captain and put it down before things get really out of hand. One should be good at an EOL, maybe not expert for a private pilot but this skill is being gently but deliberetly whittled away by the regulators !

[sycamore]

Gazelle `hyd`on/off` switch was always on the collective,so hands were on cyclic and collective,feet on pedals....
Why should it yaw to the right as the lever came up..?
were the accumulators charged correctly...? if they were ,then it should be a soft changeover..?
Was the aircraft engineer cleared to do rotor running..? It is not unknown for a Gazelle to get ground resonance...

[[email protected]]

Good point about the yaw As for the accumulators, it doesn't sound like much was done correctly.

[John R81]

I think that yaw can occur in that situation. First there might not have been enough right peddle to counteract yaw without the help of ground friction and when the lever comes up you lose ground friction, so around you go.


Also, if the lever came up the thrust / drag on the blades increases and the governor reacts to maintain RRPM by adding torque, so surely the rise of the collective would increase torque. Or am I missing something here?

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Both of those would cause a yaw left but it was reported to have yawed right - it might be a mistake in the reporting or report writing though.

[md 600 driver]

You have also got to take into account that this was an engineer without a pilots license or flight training ,the helicopter lifted off on its own and came to rest on the ground things may have got a bit fuzzy as to what happened got to be thankful no major Injury happened to him or anyone else standing nearby ,the aircraft can be replaced humans can't
I do know the owner and I can understand he was a bit pxxxxd off which is understandable

[claudia]

John R81, Thanks for the alert re Serbian o/h of Astazou engines. I knew this but no one would listen.! Now have a friend with one very worried, anyone know any more? Thanks.