Lightning - dangerous for some....
Guest
Posts: n/a
Airlines in Canada use a Thor Guard System that determines the amount of electricity in the air when thunderstorms are nearby.
When the system indicates a certain level a red alert is called and all ramp operations, including refuelling is halted.
When the system indicates a certain level a red alert is called and all ramp operations, including refuelling is halted.
Guest
Posts: n/a
alosaurus
Surely the flame arrester to which you refer only stops any flame getting back into the tank, it can't do anything to stop the fuel vapour already vented from igniting? What about aircraft other than "modern jet aircraft"? I should imagine that the CAP provisions address isues wider than that possibly prevented by the flame arrester anyway.
Surely the flame arrester to which you refer only stops any flame getting back into the tank, it can't do anything to stop the fuel vapour already vented from igniting? What about aircraft other than "modern jet aircraft"? I should imagine that the CAP provisions address isues wider than that possibly prevented by the flame arrester anyway.
Guest
Posts: n/a
Even the presence of flame arrester may not be sufficient. Checking through some of the literature, I found a reference to where a fuel/air mixture was “spontaneously ignited by a hot spot directly opposite a lightning strike to a [aircraft] fuel tank” (Bragg 1968). Bit of an old reference, and I am sure fuel tank design has moved on since then. However, it does suggest that caution may still be the prudent course of action. Creating a fuel/air mixture, even though venting, does seem to be taking the risk of encouraging a lightning induced flame.
Another possibility is intercepting the lightning stroke corona by way of a corona shield on pipes venting a fuel/air mixture. This is normal practice for the fixed, permanently venting, vents at chemical plants and such like. Is there a similar corona shield arrangement on the vents from aircraft fuel tanks? If so, then I imagine it is theoretically safe to continue fuelling if the connection into the tank is vapour tight. ‘Theoretically’ is the key word here, as I, from a personal point of view, would not feel comfortable putting the theory to the test!
Another possibility is intercepting the lightning stroke corona by way of a corona shield on pipes venting a fuel/air mixture. This is normal practice for the fixed, permanently venting, vents at chemical plants and such like. Is there a similar corona shield arrangement on the vents from aircraft fuel tanks? If so, then I imagine it is theoretically safe to continue fuelling if the connection into the tank is vapour tight. ‘Theoretically’ is the key word here, as I, from a personal point of view, would not feel comfortable putting the theory to the test!
Guest
Posts: n/a
I had occasion to change over over a ground station VHF antenna at LGW one thundery day, not being the brightest of chaps, I didn't think about the possibility that it might result in a static discharge, but it did! The suprising thing at the time was that it didn't stop, the end of the coax lead continued to earth almost continually. If a 1 m whip antenna can induce such current I wonder what potential there is in an aircraft.
As a by, the recent thunderstorms which rattled by LTN resulted in me having to replace my modem and graphics card in my PC, thinks I be investing in a surge protector.
As a by, the recent thunderstorms which rattled by LTN resulted in me having to replace my modem and graphics card in my PC, thinks I be investing in a surge protector.
Guest
Posts: n/a
In California and possibly other states, gas stations for cars have a vapour recirculating system. A rubber 'outer' tube on the nozzle, fits around the inlet point and the displaced vapour is sucked up. It is then condensed and returned to the storage tank.
This prevents polluting vapour being vented to the air and, I gather, allows the petrol company to sell the fuel a second time!
If aircraft tanks are simply vented during filling, a vapour collection hose would collect a significant amount, methinks.
------------------
A window seat on the sunny side of the aircraft, please!
This prevents polluting vapour being vented to the air and, I gather, allows the petrol company to sell the fuel a second time!
If aircraft tanks are simply vented during filling, a vapour collection hose would collect a significant amount, methinks.
------------------
A window seat on the sunny side of the aircraft, please!
