Be ready to Wobble

[pelmet]

C-FEBE, a Viking DHC-2 Beaver floatplane, operated by Harbour Air Ltd., was on a VFR flight
from Nanaimo Harbour (CAC8), BC to Sechelt/ Porpoise Bay (CAX3), BC with the pilot and 3
passengers on board. Shortly after takeoff, at about 300 feet above sea level, the fuel pressure
warning light illuminated. The pilot completed the cause checks, and switched fuel tanks as a
precaution but the fuel pressure indication remained at 0 psi. The airplane’s engine (PRATT &
WHITNEY-USA, R-985) failed shortly thereafter. The pilot performed a forced landing straight
ahead on the water and radioed for the company to prepare the Assist Boat. The pilot was able to
restart the engine using the manual fuel pump and then taxied back to the dock unassisted.
A company maintenance inspection determined that the engine driven fuel pump drive shaft had
sheared. They filed a Service Difficulty Report (SDR) with Transport Canada. The fuel pump was
replaced and the aircraft was returned to service.

I have flown several aircraft with wobble pumps over the years. It is my understanding that the Beaver has one as well(although apparently, an electric boost pump can be installed).

If the engine is losing power and there is an indication of a loss of fuel pressure....start pumping(although a power off landing as done in this case may be a good option depending on circumstances).

Seeing as you may have to pump for a long time to get to a safe landing location, if you are fortunate enough to be in an aircraft with two cockpits(such as some WWII aircraft in tandem) and also have a passenger, you may want to get the passenger to do the pumping. If alone, it might get interesting doing an approach having to pump and fly at the same time.

It would be interesting to hear any stories from people who had to wobble to keep the engine running until landing. Perhaps you only need occasional pumps pr maybe you need to pump a lot depending on power setting and aircraft type.

[digits_]

I've had to wobble a Pitts S1 due to a loss of fuel pressure. I caught it before the engine actually failed, but one wobble every 10 seconds was already exciting enough. Couldn't imagine doing it constantly while flying. They are usually not positioned in a very ergonomical location.

[pelmet]

I've had to wobble a Pitts S1 due to a loss of fuel pressure. I caught it before the engine actually failed, but one wobble every 10 seconds was already exciting enough. Couldn't imagine doing it constantly while flying. They are usually not positioned in a very ergonomical location.

Thanks,

Maybe they are designed so that continuous wobbling is not required. What general power setting required a pump every ten seconds.

[digits_]

I've had to wobble a Pitts S1 due to a loss of fuel pressure. I caught it before the engine actually failed, but one wobble every 10 seconds was already exciting enough. Couldn't imagine doing it constantly while flying. They are usually not positioned in a very ergonomical location.

Thanks,

Maybe they are designed so that continuous wobbling is not required. What general power setting required a pump every ten seconds.

Pretty much every power setting. I noticed it at full power first when the pressure dropped to zero abruptly, started pumping and reduced power gradually.