NR / SPS
I am a expert on the fuel venting systems on the r22 having owned one of the machines which suffered engine stoppage in the UK.
The aircraft G-OSEE a beta with approximateley 1550 hours total time had just been fitted with a new main rotor gearbox. Whilst completing the works i was offered a new replacement kit to replace the fuel vent pipes due to reports that following inspection of some aircraft the rubber sleeves had started to close and shrink after prolonged time submersed in the fuel tanks.
Although there were no reports of engine stoppage at the time i thought a bargain at £85.00 sterling.
I was not flying the aircraft at the time but the pilot concerned explained he had flown approximately 1 hour when the engine coughed several times next thing he new the aircraft yawed violently and down he went.
At five hundred AGL with wires ahead he dumped the lever and made for a grass field he flared the aircraft a little to high perhaps and raised the lever a little to early. I estimated at about six AGL the RPM decayed the aircraft landed hard and the slowing rotor see sawed and cut clean off the tail cone just before the strobe.
He did extremely well for a pilot with 200 hours who had not flown a helicopter for five months !!!!
Back to the point the fuel caps are not vented. There are two completely seperate aluminium vent pipes one to each tank which are attached to the mast assembly. The fuel tanks are connected via a seperate vent pipe. My retro kit had been installed wrong i believe and when the aux fuel tank ran dry it created a vancum between the tanks straving the engine of fuel.
An expensive days flying with a £5000 excess on the insurance and £8500 just paid for the new gearbox but thankfully nobody was hurt.