Hot refueling

Many times to save time or a start cycle on a turbine engine, pilots and operators will perform hot refueling, or what is technically called Helicopter Rapid Refueling (HRR). The National Fire Protection Association (NFPA) publishes document 407 titled “Standard for Aircraft Fuel Servicing” which includes a section on HRR.

According to the NFPA only turbine engine helicopters fueled with Jet A or Jet A-1 fuels shall be permitted to be fueled while an onboard engine is operating. All sources of ignition must be located above the fuel inlet port(s), vents or tank openings. Ignition sources include engines, exhausts, APUs and combustion-type cabin heater exhausts. 

Some additional NFPA requirements for HRR are: 

  1. An FAA-licensed helicopter pilot shall be at the aircraft controls during the entire fuel servicing process. 
  2. Passengers shall de-board to a safe location prior to rapid refueling operations. 
  3. Passengers shall not board or de-board during rapid refueling operations. 
  4. Only designated personnel, properly trained in rapid refueling operations, shall operate the equipment. 
  5. All doors, windows, and access points allowing entry to the interior of the helicopter that are adjacent to, or in the immediate vicinity of, the fuel inlet ports shall be closed and shall remain closed during refueling operations. 
  6. Fuel shall be dispensed into an open port from approved dead-man type nozzles, with a flow rate not to exceed 60 gpm or it shall be dispensed through close-coupled pressure fueling ports. 
  7. When fuel is dispensed from fixed piping systems the hose cabinet shall not extend into the rotor space. 
  8. A curb or other approved barrier shall be provided to restrict the fuel servicing vehicle from coming closer than 10 ft from any helicopter rotating components. If a curb or approved barrier cannot be provided, fuel servicing vehicles shall be kept 20 ft away from any helicopter rotating components and a trained person shall direct the fuel servicing vehicle’s approach and departure. 

Even with these safety precautions I have talked to operators that will not hot refuel because of the increased risk.


  1. I have hot refueled since I started flying turbines in 66. It is safe and so simple that after a briefing by the pilot a passenger can do it. I sometimes fly in winds offshore that do not allow shutting down. After I started flying a crewed aircraft the pilot in the right seat would do the fueling but before that I flew several thousand hours using the passengers to refuel without incident. I could relate a story about a passenger, not mine, that screwed up but I can also relate a story about a refueler, who’s sole job was refuling helicopters, screwing up.

  2. Good info – just one more way to get in trouble in a helicopter. In our business Huma External Cargo is a hot topic – would be interested to hear your thoughts on this issue.

  3. Robert (Bob) Pillion

    August 26, 2011 at 9:21 am

    after 10,000 plus hours in helicopters with 15 years offshore where we always hot refueled if someone was available to pump the fuel and another 20 years in the Army where hot refueling was done on a selective basis, I can say that I never had or saw an incident where the refueling became dangerous.

  4. Seems to me, the most dangerous part of the operation would be the de-boarding and re-boarding of the passengers with the rotors turning per item 2.

  5. Have been hot-fueling for years (turbine) and although not the preferred method, can and is done daily. I wonder if a true study was done to compare how many fuel fires occur with “cold” fueling v “hot” fueling or if there enough incidents to obtain accurate data. Or is this a “looks bad” therefore has to be. Sometimes the mission demands a quick turn-a-round and is best suited with a hot-fuel by those that have been trained. I have to agree with Grumpy as to more injuries will occur with all that activity around a running Copter…

  6. After flying in the Gulf of Mexico since 1970 and rapid refueling hundreds of times, I have never seen an accident caused by this method of fuel transfer. The only catastrophic fuel spillages I’ve ever observed have been caused by single point pressure fuel nozzles separating from hoses; once on a North American Sabreliner that was shut down, and secondly, a Marine corps CH-46 helicopter that was also shut down. As “Grumpy” stated on 8-26-2011 the most dangerous part of the proposal is to deplane and enplane passengers in order to refuel. High winds and weather in the Gulf tip the scales in favor of keeping the engine running and the passengers on board. Could there be a catastrophe? Certainly. But the risks of confused passenger briefings and multiple startups in gusty winds far outweigh a dictum that relies on a pitifully anemic case study basis and a lack of history of events that this dictum is supposed to prevent.

  7. Thanks for the NFPA resource Tim. It’s deffinitly a “hot” topic with some people about the safty Vs benefit of this practice.

  8. Seeing as this is the 1st of Oct. I am a bit behind the response curve, but here goes anyway. I have hot-refueled both piston and turbine helicopters over some several thousand hours of fliying. During that time, utilizing proper grounding techniques and not spraying fuel all over the place, was able to successfully and safely accomplish this task. Similiar to hot-loading/offloading of a patient in the HEMS market, it boils down the operational “necessity” of the task. many arguments can be made for and against the practice. I can’t speak to the GOM but I can speak to remote are operations, that in the event you can’t get the aircraft started again, where you shut down is where you might just remain. However I must agree with the comments left by, “Grumpy, “CW” and “Emmett”, the risk of a passenger stumbling into a turning main/tail rotor is far more likely to happen.

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