What happened
On the evening of 8 August 1997, two hot-air balloons were operating in the airspace near Årsta Holmar, Sweden, during a period of high balloon activity. The Swedish balloon, SE-ZGH, a LBL 240A, had launched shortly before 19:55 hrs and ascended to approximately 1,20 and 1,600 feet. Simultaneously, the Dutch balloon, PH-IHO, a Cameron N-133, took off and began climbing to follow the group.
While the pilot of SE-ZGH was preoccupied with attempting to contact air traffic control via radio, the Dutch balloon ascended into the path of the Swedish aircraft. A passenger on the Swedish balloon alerted the pilot to the approaching aircraft, but the collision was unavoidable. The impact caused the envelope (shroud) of PH-IHO to rupture.
Following the tear, the Dutch balloon began a rapid descent of approximately 1,000 feet per minute. To mitigate the fall, the crew and passengers jettisoned two LPG cylinders as the pilot engaged the burner. The balloon eventually crash-landed in a wooded area of Årsta Holmar. The treetops helped decelerate the basket, which landed upright. The pilot of PH-IHO sustained a minor injury, and some passengers suffered minor burns and shock, but there were no fatalities.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the flight paths, meteorological conditions, and the functionality of the aircraft equipment. The investigation confirmed that the weather was favorable, with good visibility and light winds.
Technical analysis of the communication equipment in SE-ZGH revealed that the radio was only functional as a receiver, which likely contributed to the pilot's preoccupation with the device. The investigation also reviewed the organizational requirements for commercial balloon operations in Sweden, noting that the regulations at the time did not distinguish between private and commercial pilot certification requirements.
Findings
- The primary cause of the accident was a lack of attention by both pilots.
- The pilot of SE-ZGH failed to maintain an adequate lookout while attempting to use the radio.
- The pilot of PH-IHO ascended into the path of the other aircraft.
- The collision resulted in the structural failure of the PH-IHO envelope.
- The life jackets on board PH-IHO were difficult to access quickly due to their packaging and mounting.
Safety action
The investigation highlighted the need for more stringent regulations for commercial balloon operations. The SHK recommended that the Civil Aviation Administration consider implementing specific commercial pilot certificate requirements and mandating the use of life jackets for flights conducted primarily over water.