Hawker Hunter F.Mk.58A, G-PSST / HABL 003115, Heritage Aviation Developments Ltd.
This picture is © Kev Slade and may not be used or published without permission.
Registration: G-PSST
Construction Number: HABL 003115
Model Hawker Hunter F.Mk.58A
Operator: Heritage Aviation Developments Ltd.
Airport: Cotswold Airport (Kemble) (EGBP), UK - England
Airshow: Kemble - Cotswold Airshow - 2011
Photographer: Kev Slade
Date Taken: 19/06/2011
Date Submitted: 30/06/2011
If you look below the intake you can see something 'venting'. The following statement from pilot Jonathon Whaley was taken, with permission, from the excellent online aviation magazine 'Global Aviation Resource' (See>>> http://www.globalaviationresource.com/) and gives the full story behind this. "Miss Demeanour vented some fuel and air at high power settings. This was brought about by one (of several fitted to the fuel system) pressure relief valves operating to relieve air pressure used to pressurise the fuel transfer system. Indications in the cockpit showed that the air pressure, known as the Transfer Pressure, was actually normal. "The amount of fuel vented, or the rate of venting, can be compared to mist or steam in that it appeared outwardly copious, but in reality, was imperceptible on the fuel gauges. Investigations as to why the venting was taking place were carried out and valves checked and changed. These changes required the flight of the aircraft to confirm success, or failure, of the rectification. "The display on the Sunday was cut short because it was obvious that replacing the last valve we checked had not fixed the problem. It would have been possible for Miss Demeanour to participate in the mass formation as on Saturday, as that flight had shown that such a display could be carried out without venting, but a decision was taken not to. "By a process of elimination, we had isolated the sequence of valve positions that were causing the problem. We had also established that the venting only took place at high power settings (above 7200rpm) and that she did not vent fuel at normal cruise power settings of 6600 - 6900rpm. "The cause of the venting was the sticking of the Refuelling Pressure Relief Valve. This comes in to operation during refuelling to protect the aircraft's tanks from being over pressurised by the fuel bowser and operates at a lower pressure than the series of normal Fuel Pressure Relief valves. "With this valve stuck in the Refuelling position (there is no external indication), when the air pressure from the engine rose to maximum at high power settings, it allowed the air to vent along with fuel. There are two vents, port and starboard, inboard and in front of the wheel wells and these allow âsafe' venting. That is their purpose. "At no time did the venting jeopardise the aircraft's safety or integrity, nor anyone else's, apart from the smell of JETA1. The final take off from the Cotswold Airport was followed by a flypast of the tower at cruise speed and power. This was to demonstrate that the flight back to Exeter could be made without venting."
Picture ID:1297497