fbpx

 

Just wondered what opinions there were on the following scenario that happened a couple of weeks ago. I was not in the aircraft so this is secondhand but I do have an interest in the aircraft.

Alpi Pioneer 300 with 912ULS (320hrs) weather conditions sunny 23degC temp/dew point quite close but not sure exactly.

After back track and longer than normal run up due to passenger familiarization of avionics (15-20mins on ground) power checks completed, all normal, Ts&Ps normal, prop cycled etc. On take off aircraft accelerated normally and climbed initially fine then at 300ft engine went lumpy and lost power, not entirely but enough that P1 had to stick it in a field. where unfortunately aircraft was badly damaged but no injuries.

Previous 8 hours of operations in similar conditions were fine with no problems. Aircraft had been refueled day before with E10 Mogas. Fuel check for contamination (water) was clear.

Were obviously suspecting fuel, vapour lock, carb icing etc but I'm interested to hear other peoples opinions as to which they think most likely or even other potential causes. Engine on inspection was intact i.e not push rods etc.

 

 

  • Re: 912ULS Engine Failure after TO

    by » 3 months ago


    This sounds like a classic case of vapor lock. Is the aircraft equipped with a fuel flow transducer? What kind of instruments does the aircraft have? The only way to verify if the engine experienced vapor lock is if the fuel system has a fuel flow transducer and recorded engine data from a Dynon or Garmin instrument. If you see a spike in fuel flow (8.5 - 11 GPH), you know you are experiencing vapor lock as the impeller in the transducer speeds up when vapor passes over it.

    Here is an article that will help explain more - https://www.rotax-owner.com/en/flightsafety/476-ai476

    One way to help prevent vapor lock when operating on a hot day is to run 100LL, mix your auto fuel 50/50 with 100LL, or use SWIFT fuel, as this will lower the vapor pressure in the fuel and help prevent vapor lock.


  • Re: 912ULS Engine Failure after TO

    by » 3 months ago


    Followup questions regarding the fuel, is the aircraft equipped with an electric fuel boost pump and was it on during taxi, run up, and climb out? Is the aircraft equipped with a fuel return line routed to a fuel tank? 


  • Re: 912ULS Engine Failure after TO

    by » 3 months ago


    Certainly sounds more like a fuel issue rather than icing.

    Answering Jim Isaacs questions (above) will help narrow the potential answers considerably

    I fly in Australia and have experienced fuel vaporisation on several occasions when ambient temperatures were in the high 30C's, never below 30C


  • Re: 912ULS Engine Failure after TO

    by » 3 months ago


    Thanks guys

    The aircraft is fitted with electric boost pump and that was I believe on for T/O, The aircraft has a vapour return line that bleeds back to the left wing tank. Aircraft is fitted with GNS430 and 2 MFD's with fuel transducer so point regarding spike in the fuel flow data is noted and will investigate. I'll let you know what we find. Can we rule out carb icing?


  • Re: 912ULS Engine Failure after TO

    by » 3 months ago


    I don't think you can ever rule out icing, however the ambient temperature and high power setting would suggest this is an unlikely scenario.

    Over its 320 hrs of service, has the aircraft had a history of fuel vaporisation problems?

    The use of an ethanol blend petrol, is probably not the best choice of fuel, particularly in high ambient temperature situation's.

    Assuming the boost pump was running, I am surprise that the engine did not recover and allow a return to the field under power.

    Did the pilot check for both mechanical pump and boost pump fuel pressure before take -off?


You do not have permissions to reply to this topic.