Phoenix, AZ, USA
N7244X
Balloon Works Firefly 11
The pilot and 10 passengers were dragged across desert terrain in a balloon, following the pilot's attempt to land. After an uneventful flight, the balloon touched down and the pilot initiated the deflation sequence. Several seconds into the deflation, the balloon's vent line separated. The separation occurred inside the balloon's envelope, resulting in the deflation mechanism becoming reseated. The surface wind increased and the pilot lost control of the balloon. Several passengers shouted that they wanted to egress the balloon carriage, but the pilot advised them that the change in weight would cause the balloon to become airborne. The carriage was dragged about 1,600 feet across terrain, colliding with cactus, rocks, and bushes. After the accident, the failed vent line was examined at the manufacturer's facility. The line construction was in conformance to the manufacturer's specification. Deterioration of the core fiber was typical of that resulting from flexural fatigue. However, due to the absence of information regarding the rigging configuration and/or conditions of use, the cause of the core-fiber deterioration was inconclusive. The manufacturer noted that the failed core fiber points at the failure point were consistent with one or more of the following conditions: insufficient bend radius while rope is under load; pinching of rope between objects; severe localized overloading.
HISTORY OF FLIGHT On February 13, 2004, at 0925 mountain standard time, a Balloon Works Firefly 11, N7244X, was dragged across desert terrain after attempting to land near Phoenix, Arizona. Hot Air Expeditions was operating the balloon under the provisions of 14 CFR Part 91. The commercial pilot and two passengers sustained minor injuries; eight passengers were not injured. The balloon sustained substantial damage. The local area sightseeing flight departed north of Phoenix about 0845. Visual meteorological conditions prevailed, and a flight plan had not been filed. In a written statement, the pilot reported that he departed in calm conditions and preformed both low level (10 to 20 feet above ground level) and high level (5,000 feet above ground level) maneuvers for the purpose of sightseeing. Prior to final approach, he advised all 10 passengers of the standard landing posture to assume during the landing phase of flight. He initiated a standard "stair-step" landing approach and directed the passengers to assume the landing position. The balloon touched down, and he advised the passengers to stay aboard. The initial touchdown point was at 33 degrees 44.802 minutes north latitude and 112 degrees 04.227 minutes west longitude. After touchdown, the pilot initiated the deflation sequence. Several seconds into the deflation, the balloon's vent line separated. The separation occurred inside the balloon's envelope, resulting in the deflation mechanism becoming reseated. The surface wind increased and the pilot instructed the passengers to stay down, inside the bottom of the carriage. The balloon began to slide across the terrain and tipped over. The balloon continued to be dragged across the deflation area, over rocks and vegetation for about 1,600 feet. During the accident, the pilot remained in the pilot compartment, and repetitively told the passengers to stay inside the carriage until the balloon came to a complete stop. The balloon came to rest at 33 degrees 44.595 minutes north latitude and 112 degrees 04.411 minutes west longitude. In a written statement, a passenger (who had also flown on a hot air balloon with the same operator about 3 months prior), reported that before departing the operator told him that there was a low probability that the balloon ride would be able to proceed, due to strong wind conditions. After selecting a different departure area than originally planned, the pilot made the decision that conditions were calm enough to fly. About 30 minutes into the flight the balloon began to descend. The pilot announced, about 40 feet above ground level, that they would be landing, which equated to about 10 seconds. The pilot mentioned that it would be a rough landing and told him the passengers to "hold tight." The balloon was moving fast toward the ground in a diagonal approach path. The balloon touched down hard and bounced along the ground. The pilot instructed the passengers to crouch down on the bottom of the carriage. Due to the small space, the passenger was only able to bend down. Several passengers shouted that they wanted to egress the carriage, but the pilot advised them that the change in weight would cause the balloon to become airborne. The carriage was dragged across terrain, colliding with cactus, rocks, and bushes. AIRCRAFT INFORMATION The balloon was a Balloon Works Firefly 11, serial number F11-008. The manufacturer reported the envelope was built in 1999, and was equipped with a Thunder and Colt carriage (installed under an STC (supplemental type certificate)). The pilot reported that the balloon had a total time of 914.4 hours at the time of the accident. The last annual inspection was done 14.8 hours prior to the accident, on November 11, 2003. METEOROLOGICAL INFORMATION At 0953, the aviation routine weather report (METAR) from the Automated Surface Observing System (ASOS) at Phoenix Deer Valley Airport, located 3.3 miles southwest of the accident site, was reporting winds variable at 5 knots. The pilot stated that during the accident, the wind was from 360 degrees at 5 knots, gusting to 15 knots. TESTS AND RESEARCH Upon the request of the Safety Board, the Federal Aviation Administration inspector submitted the vent line to the manufacturer for examination. The failed vent line was a ¼-inch Kexlon II, which was about 52 feet in length. Construction of the line was verified as correct per manufacturer's specification, and the manufacturer deemed the overall condition of the rope to be classified as "Fair/Moderate Use." Examination of the vent line revealed that, about 6 feet in from one end of the line, the rope had completely separated. Moderate cover abrasion was located throughout the line. About 5 feet in from the opposite end of the original line, a partial rupture of the cover braid had occurred. Also noted were localized, melted fiber seen at the margins of the ruptured cover. At the point of rupture, there was slight damage to the exposed area of the core braid. Stripping of the cover revealed severe abrasion damage to the Kevlar fiber in the core braid. The degree of the damage prevented residual strength testing of the rope. The manufacturer stated that the deterioration of the core fiber was typical of that resulting from flexural fatigue. However, due to the absence of information regarding the rigging configuration and/or conditions of use, they were unable to determine the cause of the core-fiber deterioration. The manufacturer noted that the failed core fiber points at the failure point were consistent with one or more of the following conditions: insufficient bend radius while rope is under load; pinching of rope between objects; severe localized overloading.
the failure of the deflation vent line, which resulted in the pilot not being able to control the balloon in the increased wind conditions.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
