Mogas - UK accident
Posted: Sun Nov 18, 2007 8:00 am
'Hello to all,
Some of you on this forum will know me as a member of the Fairchild
Club and of my long standing interest and continuing research into
the production and service history of the Fairchild M-62's and F-
24's. I must make it clear that I am neither a professional
historian nor have I any practical experience of owning or flying any
aircraft.
I read with great interest the thread relating to Mogas and have
debated for several days whether or not to contribute. In August
1998 there was an accident involving a Fairchild PT-19A in the UK
which had fatal consequences for the restorer, owner and pilot,
Richard Fox.
I met Richard Fox on three occasions and we had corresponded on the
history and provenance of his ex-Uruguayan PT-19A for sometime. This
was not the first vintage aircraft Richard had restored and in my
judgement his skill, workmanship and his attention to detail were
first class. It was therefore a great shock when, during the evening
of August 15, 1998, I first heard of his fatal accident .
Even before the accident report was published one of AAIB
investigators made it clear to me that after eliminating several
possibilities suggested by the eye witness reports and after an
analysis of the fuel remaining in the tanks (fortunately, there was
no post crash fire) they were coming to the conclusion that a "vapour
lock" in the fuel lines had occurred and that the volatility of the
motor gasoline was the major cause.
The accident report can be read or downloaded via either of the
following links, assuming your computer has Adobe Reader software:
http://www.aaib.dft.gov.uk/publications/bulletins/april_1999/fairchild
_500172.cfm
http://www.aaib.dft.gov.uk/cms_resources/dft_avsafety_pdf_500172.pdf
There are several points in the text that I feel are worth further
consideration:
Whilst not familiar with Woburn Park, the mention of the parkland
containing many trees probably indicates why the pilot was unable to
attempt a forced landing straight ahead when the engine first
faltered and why he initiated a turn, possibly to avoid these trees,
which developed into a spin immediately after the engine failed
completely. I am told these obstructions were relevant in a Gipsy
Moth accident at an earlier Moth Rally at Woburn Park.
I felt at the time of the publication of the report, and still feel
today, that the potential consequences of using Mogas in the UK were
not highlighted sufficiently. I cannot comment as to the situation
in the USA, but understand that Mogas can be approved for use in the
Fairchild M-62 in the USA. I also understand it is commonly used by
operators there and despite the ambient temperatures reached in some
US states (recalling my own visit to Oshkosh in August 1999!) being
much higher than that reached on a summer's afternoon in the UK -
there does not seem to be a history of this particular problem on
the western side of the pond. To the best of my knowledge there
have only ever been three other civil registered M-62's operated in
the UK and AFAIK, none of these suffered this type of engine failure.
From what is said in the AAIB report it seems likely the problem may
lie with the fuel Richard was using, and possibly, with the standards
set in the UK for gasoline for automobile use. If the problem of the
volatility quality of UK Mogas was the root cause then this is of
little consequence to most readers of this forum. However, there may
well be other operators of US vintage aircraft outside the States,
who whilst not having the official approval for the use of Mogas in
their machines, are well aware this is approved for their aircraft in
the USA and consequently make regular use of it, specially if like
Richard, they operate out of a small strip with no Avgas facilities.
It may be that the AAIB took the view that as the fuel being used was
not approved for use in this type of aircraft by UK authorities and
was therefore the responsibility of the desceased owner and as there
were no other current British-registered examples it needed no
further action beyond the usual publication of accident report.
I would imagine the circumstances of this accident are more relevant
in the case of a low-wing aircraft where the fuel is lifted from wing
tanks or the center section and less so in the case of an aircraft
where the fuel is initially gravity fed from tanks in high set wings,
such as the Model 24.
Having owned an ex-British Army of the Rhine 'Lightweight' Land Rover
for a period of twelve years, 'vapour lock' was a problem I had heard
of prior to these events, and had some personal experience of.
However, the embrassment of a failure of a vehicle to respond to your
right foot are not generally as serious as that of an aircraft engine
failure.
Hope some of you might find the AAIB report of interest.
Tony Broadhurst'
Some of you on this forum will know me as a member of the Fairchild
Club and of my long standing interest and continuing research into
the production and service history of the Fairchild M-62's and F-
24's. I must make it clear that I am neither a professional
historian nor have I any practical experience of owning or flying any
aircraft.
I read with great interest the thread relating to Mogas and have
debated for several days whether or not to contribute. In August
1998 there was an accident involving a Fairchild PT-19A in the UK
which had fatal consequences for the restorer, owner and pilot,
Richard Fox.
I met Richard Fox on three occasions and we had corresponded on the
history and provenance of his ex-Uruguayan PT-19A for sometime. This
was not the first vintage aircraft Richard had restored and in my
judgement his skill, workmanship and his attention to detail were
first class. It was therefore a great shock when, during the evening
of August 15, 1998, I first heard of his fatal accident .
Even before the accident report was published one of AAIB
investigators made it clear to me that after eliminating several
possibilities suggested by the eye witness reports and after an
analysis of the fuel remaining in the tanks (fortunately, there was
no post crash fire) they were coming to the conclusion that a "vapour
lock" in the fuel lines had occurred and that the volatility of the
motor gasoline was the major cause.
The accident report can be read or downloaded via either of the
following links, assuming your computer has Adobe Reader software:
http://www.aaib.dft.gov.uk/publications/bulletins/april_1999/fairchild
_500172.cfm
http://www.aaib.dft.gov.uk/cms_resources/dft_avsafety_pdf_500172.pdf
There are several points in the text that I feel are worth further
consideration:
Whilst not familiar with Woburn Park, the mention of the parkland
containing many trees probably indicates why the pilot was unable to
attempt a forced landing straight ahead when the engine first
faltered and why he initiated a turn, possibly to avoid these trees,
which developed into a spin immediately after the engine failed
completely. I am told these obstructions were relevant in a Gipsy
Moth accident at an earlier Moth Rally at Woburn Park.
I felt at the time of the publication of the report, and still feel
today, that the potential consequences of using Mogas in the UK were
not highlighted sufficiently. I cannot comment as to the situation
in the USA, but understand that Mogas can be approved for use in the
Fairchild M-62 in the USA. I also understand it is commonly used by
operators there and despite the ambient temperatures reached in some
US states (recalling my own visit to Oshkosh in August 1999!) being
much higher than that reached on a summer's afternoon in the UK -
there does not seem to be a history of this particular problem on
the western side of the pond. To the best of my knowledge there
have only ever been three other civil registered M-62's operated in
the UK and AFAIK, none of these suffered this type of engine failure.
From what is said in the AAIB report it seems likely the problem may
lie with the fuel Richard was using, and possibly, with the standards
set in the UK for gasoline for automobile use. If the problem of the
volatility quality of UK Mogas was the root cause then this is of
little consequence to most readers of this forum. However, there may
well be other operators of US vintage aircraft outside the States,
who whilst not having the official approval for the use of Mogas in
their machines, are well aware this is approved for their aircraft in
the USA and consequently make regular use of it, specially if like
Richard, they operate out of a small strip with no Avgas facilities.
It may be that the AAIB took the view that as the fuel being used was
not approved for use in this type of aircraft by UK authorities and
was therefore the responsibility of the desceased owner and as there
were no other current British-registered examples it needed no
further action beyond the usual publication of accident report.
I would imagine the circumstances of this accident are more relevant
in the case of a low-wing aircraft where the fuel is lifted from wing
tanks or the center section and less so in the case of an aircraft
where the fuel is initially gravity fed from tanks in high set wings,
such as the Model 24.
Having owned an ex-British Army of the Rhine 'Lightweight' Land Rover
for a period of twelve years, 'vapour lock' was a problem I had heard
of prior to these events, and had some personal experience of.
However, the embrassment of a failure of a vehicle to respond to your
right foot are not generally as serious as that of an aircraft engine
failure.
Hope some of you might find the AAIB report of interest.
Tony Broadhurst'