Note to Reader: All personnel should be trained on specific equipment that they will be using in hot fueling operations (very much like the specific training required for towing aircraft). Sign-offs acknowledging this training should be categorized by specific aircraft type and all appropriate hand signals and fueling procedures reviewed by both line personnel and flight crews to confirm proper understanding by all parties.
This article is intended to provide guidance on performing hot fueling procedures safely by utilizing practical knowledge and standards set forth by the National Fire Protection Association NFPA 407 Chapter 5 section 21 which allows “rapid refueling” of “turbine engine helicopter fueled with JET A or JET-A1” only. As always, your company policies and procedures take precedence over these guidelines. This article is not an endorsement for performing hot fueling - only guidance on making it as safe an operation as possible.
Hot fueling can be defined as fueling with the main aircraft engine running. Additional precautions to normal fueling operations should be followed to prevent aircraft fire during hot fueling operations. This operation should not be considered a routine task, it should be done with extreme care, and only when operationally necessary. Additionally, it is a good practice that a written agreement between the two participating parties be in place in advance of this type of operation stating all areas of responsibility and liability of training requirements.
PPE is a must
The first area of ensuring safety in any operation is personal protective equipment, for hot fueling this should include: fuel-resistant gloves, safety boots or leather boots with non-skid soles, safety glasses or goggles, protective clothing (100 percent cotton or Nomex) and adequate hearing protection. For these types of operations, it is imperative that full PPE is worn, especially safety glasses or goggles to avoid dust, dirt, etc., from getting blown into eyes. Adequate hearing protection is also required as the prolonged exposure in such operations can have a severely detrimental effect on hearing.
There are some key points to consider in the performance of hot fueling operations, they should include:
- Equipment or physical plant conditions that could adversely effect the results of the operation
- Areas of concern that could result in personal injury or affect the safety of the operation
- Primary causes or effects of a fuel product spill
- Equipment or procedures which might make performance of the task easier or more efficient
Ideally, details of the requirements for carrying out the operation of hot fueling should be discussed in detail and agreed upon by all parties concerned before training for such activities can commence. This is essential for ensuring both flight crews and fueling personnel understand all the conditions required for hot fueling. Items such as hand signals are to be agreed upon between flight crew and fueling operations personnel prior to the start of any hot fueling operation to ensure clear understanding.
It is best advised that fueling operations not take place with passengers on board, unless in the case of emergency ambulance flights, and where the passengers are unable to leave the aircraft. If passengers are to remain on board, it is highly recommended that a two-person fueling crew be utilized. With this two-person operation, one would concentrate on the fueling criteria such as connecting the bonding cable, deploying the fueling hose, and controlling the fueling while the other would remain in clear eye sight of both the refueler and a flight crew member in addition to being in the vicinity of both an emergency stop button, and fire fighting equipment. All personnel involved in the hot fueling should be aware of the location of emergency stop buttons. Where this is not feasible, consideration ought to be given to the safety of carrying out the operation.
Approach the aircraft with extreme caution
When approaching the aircraft, the first thing that needs to be checked is that fire fighting equipment should be available and in position at the fueling operation. There should be at least a 20-pound extinguisher (checked prior to fueling).
Extreme caution must be exercised when approaching the aircraft, according to type, from front or side, and only when instructed by an aircraft crew member. Fueling vehicles shall be positioned with at least 30 feet from any rotor tips of the aircraft. The aircraft should preferably be nose into the wind. Training should include the best entrance point for approaching the aircraft and the best exit route; many times the exit will be along the same path as the entrance. No one should approach or walk to the rear at any time – avoid engine exhaust and the tail rotor.
In order for the fueling operation to begin, information regarding the fuel requirements should be relayed to the fueling personnel and clearly understood.
Wherever possible, advance information concerning aircraft type and requirements should be obtained before the aircraft is at the agreed upon refueling point. All vehicle checks must be completed, and any required fuel sampling performed prior to beginning fueling operations. The aircraft should be signaled into position and all personnel remain clear until flight controls have been neutralized and engine speeds brought to ground idle.
Once in position, and the flight crew has signaled that fueling operations may commence by authorizing approach of personnel to aircraft, fire fighting equipment shall be put into place and the bonding cable connected. It is important to note that static charges can take up to three minutes to dissipate. Utilization of a “curb or other approved barrier” will allow any mobile equipment to approach within 10 feet of any rotating component while the lack of any “curb or other approved barrier” will restrict any vehicle from coming any closer than 20 feet.
Each person must remain in clear line-of-sight with each other
During the fueling, all personnel involved should be trained and familiar with the location and operation of emergency shutoff controls and fire fighting equipment. Personnel shall be positioned as agreed and remain observant and in clear eye-sight of refueling personnel and the pilot at the controls. Only then should a fueling hose be brought to the aircraft and fueling commence.
The flow rate is to be the minimum practicable and should never exceed the aircraft's recommended flow rates. Pump speed should be as close to idle speed as possible so not to exceed 60 gpm flow rate. In the case of single-point pressure fueling, the main control of fuel flow will be a dead-man control device which has the ability to stop the flow of fuel with one single motion. When using an over-wing nozzle, the nozzle itself acts as the dead-man control.
Refueling should stop immediately if there is any spillage of fuel and must not be restarted until cleanup is complete and the area made safe. It is important with any aircraft not to fill to capacity during hot fueling in order to prevent spillage which can be the precursor to a fire.
Fueling aircraft and operating around motorized equipment are inherently very dangerous; combining these two activities in the case of hot fueling increases that level of seriousness. It is extremely important for all parties concerned to discuss, in detail, those type operations which include hot fueling and to understand all the different hazards these operations pose. Furthermore, it is essential that all involved in hot fueling be properly trained and rehearse or train via simulation these activities prior to embarking on these types of operations. Moreover, it might be wise to have some type of indemnity agreement in place with the companies concerned prior to conducting hot fueling.