no coms

[pukeko]

Controllers are told to be aware that aircraft might go no-coms during fuel dumping - I'm trying to find out how common a requirement this might be.

Does anyone out there know anything about radio silence during fuel dumping?

Thanks for any info/advice.

[Genghis the Engineer]

Not heard of specific procedures, but it makes sense. Never a good practice to have a radio transmitter where fuel pumping is going on in the presence of air.

Most airfields have no-radio policy during refuelling on the ground, and we all know about mobile phones in petrol stations.

G

[InFinRetirement]

Ummmmm! Interesting point that.

Why are some petrol stations allowing attenna to be installed within station signs or atop their buildings? Out of sight. But producing additional income for the petrol station no doubt. The RF from these is infinitely more dangerous than mobile phones.

[Genghis the Engineer]

Yesssss, I'd wondered that myself. Hopefully somebody did some inverse square law calculations relative to the points of fuel / air mixed flow.

G

[RatherBeFlying]

Vapor from gas/diesel/jetA is heavier than air and therefore flows to lower elevations, which is why inboard power boats have bilge ventilators.

An elevated antenna is likely much less exposed to fuel vapors than a mobile at ground level and likely the engineers have worked out a formula for a safe antenna elevation.

Propane and methane fumes of course go up; so please don't mount your antenna on top of your propane tank unless you want to send it in orbit

[411A]

Due to the radiated power output...

VHF, should be no problem during refueling/fuel dumping.
HF, on the other hand, not a good idea.

[Flight Detent]

Hi all,
411A, for once, I agre with you entirely.

Errrrrr......I thought you said "no poms"... and I thought this post would be interesting!!!

Cheers

[m&v]

As 411 says;
It's a holdover from the HF era,can't check HF on the ground for the same reason-fuelling

[Self Loading Freight]

It's not so much sparks from the antenna itself that are the problem -- which you really shouldn't get -- but resonant structures in the vicinity that can create discharges. So while keeping the aerial out of the vapour is a good idea, the fact that aerials tend to be high and vapours tend to be low is just physics rather than health and safety...

R

[Mr. TCU]

RatherBeFlying,

Since you know about the buoyancy of fuel vapour, I've got a question for you. In underground parkades, they always say that propane vehicles are prohibited. Is this because the exhaust from propane is heavier than air?

[RatherBeFlying]

Mr. TCU, can't say I know for sure, but here's a couple guesses:

• Propane and CNG are under pressure; so, any leak has the potential for the entire tank of gas to end up in a confined space,
• As the vapor travels up it can contact spark sources such as electric motors in the elevators or anybody in the parking area who happens to be smoking.

A gasoline leak can be just as serious, but that's the tyranny of the majority for you.

In an accident with a fuel system rupture, you may be less likely to be barbecued with fuel that dissipates into the air rather than stuff that flows under the passenger compartment

[RomeoTangoFoxtrotMike]

Density of Propane...

Propane is heavier than air, and so any leaking propane will collect in "pools" at the lowest level in basements' etc. Any spark in the vicinity will obvioulsy have serious consequences