A highly experienced pilot of a Goodyear-branded airship that fell to the ground in flames in Riechelsheim, Germany, in June 2011 appears to have been responsible in part for the errors that led to the fatal crash during a safety tour across Europe, sponsored by the American tire company.
According to a final report on the accident by German aviation safety agency BFU, the American Blimp Corp. A-60+ blimp was likely overloaded when the pilot departed Riechelsheim Airfield for a 2-hr. sightseeing flight on June 12 with three passengers. On the previous flight that day, the pilot experienced a tail strike that broke the wheel from the airship's rudder. The blimp was also having troubles with a microphone button that was jamming, leading the pilot at one point to send text messages to his ground crew during the accident flight.
Goodyear had leased two airships—Spirit of Safety I and II—from Lightship Europe in March 2011 to visit 20 European countries as part of a road safety awareness campaign. The company's name has been synonymous with blimps since it acquired its first airship in 1917.
Built in Oregon, the 128-ft.-long A60+ uses helium for lift and two Limbach L2000 EC1 internal combustion engines for thrust. The airship, which had been registered in the U.K. since 2002, held 69 gal. of aviation gasoline in an aluminum tank behind the five-seat gondola. At the bottom of the tank were controllable valves and hoses that route the fuel to each engine, and “gascolators,” small reservoirs that trap debris in the fuel and allow for samples to be taken to check for water or other contaminants.
The accident occurred on the third consecutive flight of the day for the accident pilot, who had accumulated 12,330 hr. of airship time since 1985. Goodyear had been conducting the flights daily at Riechelsheim since June 8. The BFU did not mention whether fatigue may have played a role, but did note that the “responsible public prosecutor” ordered that no post-mortem examinations be conducted on the pilot. “Due to witnesses' statements, health problems were very unlikely,” says the BFU.
A second pilot who performed the first five flights that day noted told investigators that the airship's lifting capacity was below optimum during his flights, and he estimated the lifting capability had been further reduced by the lowering Sun angle in the late afternoon.
For the accident flight, the pilot departed with 475 lb. of ballast in a compartment that can only be accessed when the airship is on the ground. The BFU says he was aware of the loading conditions, and on the return to the airfield, texted his ground crew: “It's a heavy puppy, 15 plus. Doesn't want to fly at 2,200 rpm. I guess no hooked approaches today.” American Blimp and Lightship Europe, in an April 2013 letter to the BFU, estimated that the text message meant that the airship was overloaded by 15 ballast bags, or 375 lb. “This prompted the pilot to demand 2,200 rpm from the engines to hold the airship steady,” the companies stated.
The lack of buoyancy combined with still air at the airfield made for what the BFU describes as an “extremely difficult landing situation” for the pilot.
The three passengers described initial contact as “very hard.” All three stated that after the airship had come to a complete stop, the pilot had said it was an accident.
The BFU says it is “highly likely” that the airship's single landing gear wheels were shoved rearward at touchdown, allowing the strut to hit the ground and causing “an immense backward effective force” that then fractured the landing gear and led to a gascolator being damaged. Fuel then drained from the gascolator onto electrical components in the aft portion of the gondola, including fuel pumps and servo values, which likely caused an arc that set the fuel on fire.
The passengers “made the pilot aware of the increasing fuel smell and reported fire and heat development in the aft part of the gondola,” says the BFU. “They disembarked from the airship gondola. According to their statements, the pilot supported them to do so.”
Lightened by about 550 lb. when the three passengers jumped out, the airship lifted off again with the pilot onboard before the ground crew could reach the scene and grab the mooring line from its nose.
“The burning airship continued to ascend again up to about 220 feet and thereby drifted slowly to the east,” states the BFU. “Deformation of the envelope began with the increasing fire. Later it caved in . . . and the burning airship crashed to the ground. It burnt out completely and only the pilot's body could be recovered.”
American Blimp and Lightship Europe say the fuel leak could have been avoided if the pilot had closed the valve after the hard landing, as recommended in the operating manual.