During The Descent The Envelope Continued To Deflate Until It Was In A Streamer-Type Configuration

Location: Eloy, Arizona Accident Number: WPR24FA072
Date & Time: January 14, 2024, 07:47 Local Registration: N4961D
Aircraft: Kubicek BB85Z Aircraft Damage: Substantial
Defining Event: Loss of control in flight Injuries: 4 Fatal, 1 Serious, 8 None
Flight Conducted Under: Part 91: General aviation - Other work use

Analysis: The balloon departed with the pilot, eight skydivers, and four passengers on a sightseeing passenger and skydiving (commercial) flight. Interviews with the skydivers revealed that after about 35 minutes, the balloon reached an altitude of about 10,000 ft mean sea level (msl) and all 8 skydivers departed from the basket in 4 groups numbering 3, 2, 1 and 2 jumpers, respectively. The four passengers and pilot remained in the basket. After the jumpers exited the basket, the pilot pulled the red rapid deflation valve line 12 times to open the rapid deflation valve. This action resulted in a rapid loss of air that deformed the envelope, causing the deflation system’s control lines to drop in and around the basket, which pinched the Red-White line in the flying cables. About 46 seconds later, the pilot attempted to add hot air to the envelope and attempted to close the rapid deflation valve but, was unsuccessful. During the descent the envelope continued to deflate until it was in a streamer-type configuration. 

Additionally, at times a burner flame under the deflated envelope was observed, as the pilot attempted to inflate the balloon envelope. The balloon continued to descend until it impacted the terrain.

Witnesses saw the balloon descending toward the ground. A review of multiple mobile phone videos revealed that the balloon was descending with the envelope deflated and trailing above the basket. Postaccident examination of the balloon did not reveal any preimpact anomalies that would have precluded normal operation. According to the balloon flight manual, the rapid deflation system was designed for fast and efficient deflation of the envelope during landing below 6.5 ft above ground level to prevent the basket from being dragged in windy conditions. If the pilot had used the parachute valve to manage the descent, he likely would have been able to land the balloon without injuries. Several online videos showed the pilot using the rapid deflation system while at high altitudes in other flights, indicating that that this was a common practice for him.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- The pilot’s decision to open the rapid deflation valve during flight as a means of descending, which resulted in the deflation of the envelope and hard impact with terrain. 

FMI: www.ntsb.gov