A Cargolux Boeing 747-8F aircraft was very close to explode when fuel leaked from helicopter being transported as cargo. UK investigators said in a report published on 12 July 2018.
Incident
On 30 March 2017, Cargolux Boeing 747-8F, Reg LX-VCF was operating scheduled cargo flight CV7754 from Houston, Texas to Luxembourg with an intermediate stop at Prestwick International Airport, UK.
The aircraft arrived at Prestwick and parked on stand. As the flight crew were shutting down the engines they smelled fuel. When the ground operations agent also detected a strong smell of aviation fuel and heard the sound of running liquid when he entered the deck. He found Bell 412EP helicopter, which was being shipped as cargo on the main deck appeared to be leaking fuel from a vent on the forward right-hand side of the helicopter.
The RFFS noted that fuel was coming out of the bottom of LX-VCF’s fuselage, close to the left body landing gear, having leaked through the main deck, lower deck and avionics bay and was pooling on the apron beneath the aircraft.
The aircraft was evacuated, electrically isolated and quarantined by the RFFS. The RFFS subsequently stated that the 322 litres of fuel leaked from the helicopter.

Helicopter
The Bell 412EP helicopter was disassembled for shipping and encased in strong white plastic shrink-wrap and had been secured to a cargo pallet for the flight. During the aircraft examination, some fuel was present in the wells of the pallet and the securing straps were soaked with fuel.
No defects were noted on the Helicopter fuel system during the inspection which could have accounted for the fuel leak.

CCTV footage
Review of CCTV footage from the cargo facility showed that no walkaround was conducted and the mechanic appeared to focus his attention on the lower surface of the helicopter before shipping. He did not use any tools or remove the shrink-wrap to facilitate inspection of the helicopter. He used a cleaning spray to clean parts of the exterior surface, inserted absorbent pads between the shrink-wrap and the helicopter skin and applied some white tape over the shrink-wrap.
Shipping of dangerous goods by air
The International Air Transport Association (IATA) Dangerous Goods Regulations (DGR) describe “the entire fuel system of the engine has no free liquid and all fuel lines are sealed or capped or securely connected to the engine and vehicle, machinery or apparatus.”
Findings
Adequate steps were not taken to correctly prepare the helicopter for transport and this situation was not identified prior to it being offered for transportation by air. An inspection of the helicopter prior to travel was superficial in nature and, although no attempt was made to verify the actual fuel state of the helicopter, incorrectly concluded that the helicopter had been defuelled.