Note: in these accounts names and aircraft identities have been omitted to protect the guilty!
35 years ago, flying as rear-seat pax in a PA28 Cherokee out of Wycombe (Booker in those days!), the engine stopped at 2000ft over Marlow when the pilot switched off the fuel booster pump. It started again when, after a bit of scrabbling, he switched the fuel booster pump on again. Returning to Wycombe we discovered that the front fuel drain had stuck open and was peeing fuel. Although both the mechanical and booster pumps had been able to feed the engine and the hole in the fuel line, one pump alone could not.
About 5 years ago a C152 from Halton Aero Club left Clacton to return to Halton, suffered ‘engine failure’ and landed safely in a field. The aircraft’s tanks were found to be empty. The pilot had visually checked the fuel state before take-off and exercised all the fuel drains, including the engine fuel drain. It was found that the engine fuel drain return spring did not close the valve when the lever was released, it had to be positively returned digitally (by finger!). The pilot had been burning fuel and throwing it away at the same time!
On Saturday 11 March 2006, a Denham-based PA28 Warrior abandoned take-off when engine RPM dropped. On return to dispersal it was noticed that fuel was pouring from the front fuel drain – it had stuck open.
On the same day, Sat 11 March 2006, I arrived at Paris-Toussus in a PA28 Archer II after a 2.5 hour flight from Denham having left Denham with full tanks. We immediately refuelled and the uplift was an astonishing 145lit (consumption 51 lit/hr!). Another identical Denham-based Archer which flew alongside us and parked next to us at Toussus uplifted 85 lit (34 lit/hr). We are still trying to work out why, but you can imagine that the two main suspects are a. the bowser driver, and b. the nose fuel drain.
The PA28 nose drain is taken from the bottom of the fuel strainer that sits below the level of the fuel in the tanks, with fuel at TABS. The mechanical and electrical pressure pumps that feed fuel up to the caburetor are both above the level of the fuel in the wing tanks. If the drain sticks open it will leak under the header pressure from the tank. However, with the engine turning, the line will be effectively pressurised by the mechanical fuel pump (an the electrical booster pump) and any static leak could increase under that pressure. The POH says “After draining (tank sump and nose drains) each drain should be checked to make sure it is closed completely and not leaking.”
I’m getting a bit worried that my experience of fuel problems is accelerating. I mean, 35 years, 5 years, and now possibly two in one day.
In future I’m going to be doubly positive about closing all fuel drains after draining. I’m also going to take more notice of the fuel guages in the aircraft I fly for indications that fuel useage/balance is abnormal.
LET THAT BE A LESSON TO US ALL!
Disclaimer: The author of these missives makes no guarantee of the accuracy of these notices, and advises all readers to check the facts for themselves using the information provided
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