I also submitted a modification request to the PFA along similar
lines to John but with the return into the vent inlet. It has been
agreed by the PFA subject to fuel flow tests which I have not yet
done (nor pressure).
Regards
Paul
G-GIDY
On 6 Nov 2007, at 09:53, John Cliff wrote:
> <mx@jcliff.waitrose.com>
>
>> Hi all,
>>
>> I have a question if I may.
>> Mod 33 shows the starboard drain tank outlet used also as the
>> return line tank inlet.
>> The pictures I see with Graham Singleton's adapters for threaded
>> connections all show the return line going to the vent outlet if
>> I'm not mistaken.
>> Is this recommended, if so why?
>
> Several years ago I submitted a Modification request to PFA
> Engineering to cover a revised fuel system with aluminium pipes and
> home-brewed tank fittings, much like Graham's. The return feed
> went back via a drain outlet.
>
> Francis made several comments. One of them was that this return
> route was not the best as in the event of a serious engine bay fire
> in which the flexible hoses were destroyed it would be possible for
> fuel to be fed from the tank along this return line which could not
> be turned off. In theory most of the tank contents could feed the
> fire. Raising the return point to the vent inlet removed this
> possibility (unless you came to rest on the ground inverted, tail
> high).
>
> John Cliff
> #0259
>
>
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