Anyone flying a Rotax 912 series engine should pay attention to the "Mandatory SB-912-53" service bulletin. It deals with the replacement of the mechanical engine mounted fuel pump with a newer design. The issue is the use of an electrical fuel pump on the suction line to the engine mechanical fuel pump increases the fuel prsssure supplied to the pump and can cause the mechanical pump to fail, engine stoppage due to flooding, and the potential for massive fuel leakage. Almost all CH 601XL's use a wing mounted electric pump to feed the engine pump fuel. Both my CH601HD and CH750 fuel systems are configured this way. Many builders have installed an electric pump to "fill the carb bowls prior to start" or as a plan "B" in the even of an mechanical pump failure. A couple weeks ago my CH601HD suffered a "sudden engine stoppage" on take-off and I made a very quick landing on what was left of a very short grass field with a fence and large 50 ft trees at the end of the runway. Another 5 seconds of flight and I would be on this site selling parts of the airframe / engine / instruments. I had switched the electric "boost pump" on prior to take-off figuring if the mechanical quit it would be a "non-event"... my mistake. I was aware of an earlier TSB (SB-912-50) on the fuel pump, and assumed this one 2 years later was just a repeat of the first "inspect fuel pump TSB"     (I never read it closely).... again my mistake. A new fuel pump is $175. This is very cheap life and aircraft insurance.  Fly safe..... or at least informed.

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This SB is 3 years old. Better late than never
SB-912-053-UL 912 UL, 912 ULS, 912 ULSFR 0 0 13.04.2007 Replacement of fuel pump for Rotax engine type 912
I missed that SB... I guess I just looked at the subject and figured it was the same as the earlier "inspect or replce" SB. Some builders are using engines removed from Katanas (I am in the CH601HD), or with un documented history's which is why I mentioned it. I even found two local flyers at the airfield (RANS S7 & Aerostar Festival) that both have the "condemned" fuel pump in-service. Both bought the aircraft used and were not up to date on the SB. At least I know the reason for my engine quiting.... "my mistake". An old Bush Pilot told me long ago, "learn from the mistakes of won't live long enough to make them all yourself".
New fuel pump installed and 4 hrs of flying since the "wake up call". All is good in the land of Rotax aircraft engines.


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