Fuel drains and slopes - Enstrom 28A
Yes ... 'tis important that we can use this forum to promulgate previous experience. Off topic again but forgive me ... go back to 1973 when I tasked a pilot to deliver a humble Enstrom 28A from Shoreham to its new owner. (G-BBPO no less!)
PIC ran into weather and sensibly elected to land at a convenient hotel but on a sharp right to left down slope. Overnight heavy and continuous rain ... strong winds.
Early morning pilot was seen to drain all three drain points. Climbing out the engine failed at 100 feet with the heli suffering skid and T/R damage in the resultant auto landing, albeit remaining upright.
The Enstrom was a newish type to the UK in the early 1970s so the AIB (as it was then) got involved. Engine removed but ran normally.
As I was involved in getting the CAA PT certification I needed to do some research so I rigged up the fuel tank for some testing. First we discovered a damaged filler cap seal on the accident helicopter. Also discovered that at an 8 degree slope, the depression that surrounds the filler cap will collect water, but which doesn't quite reach the fuel filler neck. But we also discovered that with an airflow across the filler, water could get blown/possibly sucked into the tank. Probably one drop a minute. But a constant water supply and twelve hours later !
Next we learned that at the same 8 degree side slope, the centrally located fuel pick up point in the tank allowed a bare half an inch of space to inboard where displaced water could settle clear of the fuel pick up point.
Then similar to Shawn Coyle's incident, start up and run up engine was normal, lift off with left skid low still normal until the heli levelled at which point water moves inboard and enters the pick up point and engine supply pipe.
The Enstrom fibre glass tank was promptly factory modified, but I relate this yarn just to highlight how many nasty little items await we flyers. The circulation of knowledge and experience counts for everything in safety, hence the success of Gary Spender's 'informal safety evenings'.
A horrid personal example. Had I known in 2000 that the Hughes 269c type had a history of part no 234 pylon cluster cracking failures, (eight in all) ... I would not have purchased the type for my school OR if I had, I would have carried out the factory approved cluster replacement. As it was I knew nothing of the previous failures and as many of you will know my son lost his life as a result following a mid-air break up.
See many of you at Redhill Nov 26th.
Regards to all,
Dennis Kenyon.
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