During a flying session at a British Model Flying Association-affiliated club site, the pilot and his helper noticed a flash of arcing inside the flight box. The starter was immediately disconnected and the 12-volt battery removed. After this it was noticed that the bottom of the plastic flight box was bubbling, the cause of which was not immediately apparent. After 15 seconds or so, the pilot and his helper tried to remove the flight box from the pit area and, as the pilot’s helper bent over to pick it up, the flight box exploded in his face, throwing him some 30 feet and causing burns to his face and scalp, which required specialist hospital treatment.

     The explosion was caused by the ignition of half a gallon of methanol-based fuel that was stored inside the plastic flight box together with the 12-volt battery and associated circuitry. Unfortunately the flight box was so badly damaged that inspection did not reveal the detailed cause of the ignition. However, it is probable that an electrical fault ignited spilled fuel, fuel vapor, or probably both causing the plastic flight box to melt and the fuel container to ignite. Unfortunately, methanol burns with a very pale blue flame that is barely discernible in daylight resulting in the pilot and helper being unaware of the seriousness of the situation. Fortuitously, there was a source of water nearby that was used to cool the burns while awaiting medical assistance.

Fuel fires of this nature are extremely rare, but to protect against a reoccurrence we advise the following:

1. Fuel containers are stored externally on flight boxes away from potential sources of ignition such as electrical equipment, lighters, and matches.

2. If you do store your fuel within the flight box, it should be within a separate compartment within the flight box. Drain holes should be incorporated to disperse spilled fuel and the compartment should be well ventilated to disperse fuel vapor. The design of the box should prevent fuel from migrating to other compartments within the flight box in the event of a spill.

3. Mop up any spillage immediately and dispose of the mopping up materials in a safe place.

4. Do not smoke in the vicinity of fuel.

5. If you have, or suspect you might have, a fire, warn your colleagues and clear the area immediately. Remember, methanol fires are not obvious in daylight so stay well back if in doubt.

6. If the fire is small, attempt to extinguish it by using an approved extinguisher for fuel fires (foam or powder). If there is any danger of a large fire, i.e. the fuel container itself, do not attempt to extinguish the fire under any circumstances. Always exercise extreme caution and if in any doubt, stay well back and contact emergency services for assistance.

7. Do not attempt to move any burning material.

8. Be sure you know the first aid treatment for burns and where the nearest water supply is. The first few minutes in the treatment of burns is critical if the injuries are to be minimized. The quicker the burn is cooled, the less the damage to the underlying skin tissues. Burns can cause severe shock that will require treatment.

     Remember to avoid putting your fuel container into an enclosed space and never adjacent to potential sources of ignition. Should you have a fire, do not take any risks; your equipment is replaceable but you are not.

Compiled with advice from the Leicestershire Fire and Rescue Service.