Air-To-Air Refuelling

[Star Attraction]

Air-to-air refuelling, otherwise known as aerial refuelling or in-flight refuelling. Military aircraft tend to do it a lot. There are two methods:

Probe-and-drogue
Hoses are sent out from the back of a tanker aircraft. The planes to be refuelled stick their probes into the hose funnels to receive fuel.

Flying boom
Also known as boom and receptacle. One hose is sent out from the back of the tanker aircraft. The nozzle end of the hose has wings on it. A boom operator is required to position the boom so that the nozzle mates with and locks on to the receptacle of the receiving aircraft behind. Fuel transfer then begins.

Either way, you effectively have a filling station in the air.

Do any passenger aircraft do that though? Consider a British Airways Jumbo Jet flying from London Heathrow to Melbourne. En route it's likely to stop at Bombay, Singapore and Sydney to refuel. Wouldn't it be easier to refuel in-flight using either of the above methods, to save having to land, refuel and take off again three times along the way.

Alternatively why doesn't the pilot take tins of aviation fuel in the hold, to top up the tanks when required?

[Richard1978]

Re: Air-To-Air Refuelling

The only passenger service I've heard of using in-flight refueling was with the Short Empire flying boats in the late 1930s.

These would take off with fairly empty tanks & then be refuelled for a non-stop Transatlantic flight.

When fully loaded with passengers they would be too heavy to take off with a full load of fuel.

[Adam]

Re: Air-To-Air Refuelling

Air to air refuelling is a military practice. Long haul civil flights tend to call at an intermediate airport to refuel.

[Star Attraction]

Re: Air-To-Air Refuelling

Air to air refuelling is a military practice. Long haul civil flights tend to call at an intermediate airport to refuel.

My original question was "Why don't long haul civilian aircraft refuel in the air, instead of calling at intermediate airports to refuel?" (like my London Heathrow to Melbourne example).

[Adam]

Re: Air-To-Air Refuelling

Safety reasons I'd guess.

[Shado66]

Exactly.....air to air refueling can be tricky at the best of times.....Downright dangerous at the worst and if performed badly can be fatal resulting in the loss of aircraft and pilot / passengers. The military only perform it when absolutely necessary as in the Falklands, black buck mission.
For example, aviation fuel accidentally leaking from a trailing hose anywhere near a hot spot around the engine fairing could result in a potential ignition resulting in the loss of the aircraft. I guess they would rather land and refill than risk the lives of hundreds of passengers.
You've also got two very large aircraft, one filled with 100's of gallons of highly volatile aviation fuel flying in pretty close formation for a considerable period.
Just too many factors to go wrong. All in all its still safer to land and refill and take off again even considering that landings and takeoffs are an increased risk for commercial flights.

As for taking on extra fuel. The added weight of the fuel necessary would result in a major increase in fuel use especially at takeoff. This would mean that you would quickly use the equivalent amount of fuel you are carrying on board. You would therefore have to refuel using the carried fuel and also land and take on added fuel as before. Overall the amount of fuel needed for the total flight would greatly exceed the minimum fuel requirement needed for the distance traveled. Seeing as aviation fuel is the main cost factor in commercial flights, it would result in a far more costly flight apart from a massively increased carbon footprint. Not good on the wallet or the environment.

[Richard1978]

Re: Air-To-Air Refuelling

A good example of an air-to-air refueling going wrong was the 1966 "Broken Arrow" incident, when a B-52 collied with a KC-135 tanker & scattered 4 live nuclear bombs over the Spanish coast.

[Star Attraction]

Re: Air-To-Air Refuelling

A good example of an air-to-air refueling going wrong was the 1966 "Broken Arrow" incident, when a B-52 collied with a KC-135 tanker & scattered 4 live nuclear bombs over the Spanish coast.

Did the nuclear bombs explode and cause damage on hitting the ground? Presumably both planes were wrecked, in which case where did the wreckage land?

[Richard1978]

Re: Air-To-Air Refuelling

Did the nuclear bombs explode and cause damage on hitting the ground? Presumably both planes were wrecked, in which case where did the wreckage land?

Luckily the bombs weren't primed, but 3 hit the ground & leaked radioactive material. The 4th landed in the sea & was eventually found.

Both planes were destroyed, with most of the debris landing on the Spanish coastline or in the sea.