Lightning - dangerous for some....

[Few Cloudy]

Four days back in GVA, a string of thunderstorms transited overhead the field. Lightning strikes very adjacent to and possibly on the field occured.

The airport ruled that the use of headsets by groundstaff would be forbidden during the predicted time of storm activity. (due to discharge risk)

So far so good - however, the refuellers were hard at work and looked strange when
asked to stop refueling for a while: "we've got other customers waiting..."

Two points here - firstly excellent radio mic-tel socket to headset connections are available and in continuous use in Japan for instance - eliminating the discharge risk - secondly despite a good search on and off the web, I have been unable to turn up rules or recommendations about fueling in thunderstorms. Anyone got relevant info or comments to back up my nagging memory?

[WideBodiedEng]

Jobsworths! Don't DO anything then nothing will happen that you can get blamed for.

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The Stamp is mightier than the Toolbox!!

[Eli Vator]

If nothing else is forthcoming you may want to try here and fire off an e-mail or give them a ring -

Greater Orlando Aviation Authority (http://fcn.state.fl.us/goaa/contact.htm)

Orlando is allegedly the lightning strike capital of the world. They are most definately well-versed in coping with the problem. If they are unable to provide a definitive answer I'm sure they'll steer you in the right direction.

[deltahotel]

My (UK Charter co.) rule is no refuelling with a TS within 10 miles.

[CaptainSandL]

I know you can't get AVGAS in the UK with TS around, but no such problem with JETA1. I remember the the RAF used to stop AVGAS refuelling as soon as the MET Office issued a TS warning, all seemed a bit OTT.

S & L

[Few Cloudy]

Thank you guys - I am sure in the distant past I have been told it's forbidden - all info gratefully rcd.

[ExSimGuy]

Bl00dy dangerous if the Lightning is behind you and you are in his sights http://www.pprune.org/ubb/NonCGI/tongue.gif

[Evening Star]

R H Golde in his textbook ‘Lightning Protection’, reports on an explosion caused by a direct lightning strike to a fuel installation. The identified cause was ignition of the fuel air mixture, and he comments that to prevent such an explosion it is necessary to prevent emission of a fuel air mixture while an active thunderstorm is overhead. I would (and this is possibly showing my ignorance of the refuelling apparatus used on aircraft) expect it is impossible to prevent emission of fumes during refuelling and reports of refuelling during a thunderstorm are therefore surprising.

I am fairly certain that the British Army has standing instructions to prevent vehicle refuelling during a thunderstorm. It would be very surprising if the RAF does not also have the same instructions.

Interestingly enough, also in the Golde’s book there is a section on lightning strikes to aircraft, and the protection built into aircraft fuel tanks to prevent lightning induced sparks inside the tanks.

(Should explain that the dissertation for my first degree was on the probability of lightning strikes and, besides an interest in the subject, it serves me professionally to keep up to date so the comments already made on this thread are very interesting.)

[Edited for a typo.]


[This message has been edited by Evening Star (edited 23 May 2001).]

[metrodriver]

Someplaces that I have been to in the US pull everybody off the ramp, including fueling when there is a TS. first hand experience in DFW, CVG (at DHL).

[Flybywyre]

http://bestanimations.com/Nature/Storms/Storm-01.gif

[Flybywyre]

http://bestanimations.com/Nature/Storms/Storm-07.gif

[tired]

Grew up in Africa. Lots of Cbs down there. Never heard of them stopping refuelling or any other ground ops.

[Few Cloudy]

FBW

Thanks for the info flash - ow my eyes!

[HotDog]

Evening Star, the refuelling hose couplings to refuel valves (underwing) are vapour tight and would not pose any risk in TS activity and the bowser is also grounded to aircraft structure. Overwing refuelling on small aircraft however, would present a certain element of risk in those conditions.

[Hew Jampton]

HotDog
And when the fuel goes into the wings, what does it displace? Fuel vapour that is vented from the wings to atmosphere. Have a look at UK CAP 74, 'Aircraft Fuelling: Fire Prevention and Safety Measures". Both precautions, no push back headsets and no refuelling, are eminently sensible, but then we can't let safety impede punctuality and profit can we?

[This message has been edited by Hew Jampton (edited 22 May 2001).]

[Ranger One]

It's not just the risk of a direct strike that creates a hazard; there is also the matter of 'induced potential' (ever felt your hair stand on end in a storm - I have, on top of a Scottish mountain... all metalwork, ice axes etc also started buzzing... no fun at all if you are fueling, and really quite glad I wasn't flying that day! Made a very rapid descent...)

Also even a relatively distant strike to ground can cause a ground current sufficient to raise a spark... covered some of this stuff in explosives training, the same risks apply to fueling I guess.

[Capn Lucky]

I saw someone mention Central Florida as the lightning capitol. This is probably true. MCO has a policy of clearing the ramp due to multiple deaths due to lightning strikes sveral years ago. Most airlines operating in the state have policies against fueling during a storm. Also, I'm will to bet that SFB has the same policy in place.

[Few Cloudy]

All good stuff, thanks.

Hew J., UK Cap. not avbl down here - could you post a quote of 74 please?

Thanks, Few.

[Hew Jampton]

Few, from Hew!
My issue of CAP74 is slightly out of date, but it says
"The aerodrome authority - Air Traffic Control should issue guidance, depending on local conditions, as to when fuelling operations should be suspended due to the proximity of severe electrical storms."

I gather that the latest issue expands on this and places more of the responsibility on the aerodrome authority rather than ATC.

[alosaurus]

Hew J.
The CAP you refer to does not apply to modern jet aircraft which have a flame arrester in each NACA vent;thus effectivly maintaining wing tank isolation as described by HD.

[bearsden]

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.

[Hew Jampton]

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.

[Evening Star]

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!

[bigbeerbelly]

I heard that Continental had a lightning strike last week on their B777 after departing Narita. The engine reportedly caught on fire and the crew returned to the field.

[no sig]

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.

[PAXboy]

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.

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A window seat on the sunny side of the aircraft, please!