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ASN Wikibase Occurrence # 133774
Last updated: 29 October 2019
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Date:09-JAN-1998
Time:07:13
Type:Silhouette image of generic BALL model; specific model in this crash may look slightly different
Cameron R-420
Owner/operator:Global Hilton
Registration: N298AR
C/n / msn: 1
Fatalities:Fatalities: 0 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Yeso, NM -   United States of America
Phase: En route
Nature:Private
Departure airport:
Destination airport:
Investigating agency: NTSB
Narrative:
HISTORY OF FLIGHT

On January 9, 1998, at 0713 mountain standard time, a Cameron R-420 Roziere gas balloon, N298AR, known as the "Global Hilton," was substantially damaged when the bottom of the main gas cell ruptured near Yeso, New Mexico. During their emergency parachute landings, the commercial pilot-in-command (PIC) received minor injuries and the commercial second-in-command (SIC) was seriously injured. The balloon was being operated by World Flight Limited Company of Albuquerque, New Mexico, under Title 14 CFR Part 91. Visual meteorological conditions prevailed, and a VFR flight plan had been filed. The flight originated from Albuquerque, New Mexico, at approximately 0618.

The project manager stated that the flight was intended to be an around-the-world flight in the jet stream. The jet stream is a boundary layer between the troposphere and the stratosphere, normally found between 25,000 and 40,000 feet mean sea level (msl). The project manager stated that weather conditions dictated a launch window between December 15, 1997, and March 15, 1998.

The ground crew calculated the amount of helium gas needed to be approximately 176,400 cubic feet, or 42 percent capacity, based on a gross weight of 11,505 pounds and the free lift desired by the ground crew. This calculation included enough helium to provide a normal/recommended lift factor. An additional lift factor was used due to the Sandia mountains located 6 nm east, and two temperature inversions located at 2,000 feet above ground level (agl) and 10,000 feet msl. The SIC stated that a 400 pound ballast had unintentionally been left on the ground. The launch master stated that the balloon's total free lift, at lift off, was approximately 1,200 pounds.

The balloon was launched, during the hours of darkness, from Albuquerque's Balloon Fiesta Park (elevation 5,280 feet). Radar data indicated that the balloon's initial rate of climb accelerated to approximately 1,500 feet per minute (fpm). The SIC, who was flying the balloon, reported that he recognized the accelerating rate of climb and immediately began "valving off" helium to slow the climb rate, which took approximately 3 to 4 minutes. At approximately 0633, the balloon's climb rate was stabilized between 200 and 300 fpm, which the SIC maintained until 25,500 feet msl.

The SIC stated that he slowed the rate of climb to approximately 100 fpm as they approached their initial float altitude of 27,500 feet msl (see attached radar data). He reported that the sun's rays began shinning on the balloon's envelope approximately 10 minutes before leveling off. He then he noticed helium flowing down one appendix, and hesitate at a pinched point (a buckle attachment point) approximately 15 to 20 feet above the bottom opening. The SIC said that helium continued down the appendix, and "bubbled" out the bottom opening. The PIC viewed the other appendix, and he observed that it had not fully inflated. He reported that he did not see helium gas exit the opening at the bottom of the appendix.

Both pilots reported that after level off all was quiet for approximately 10 to 12 minutes, and at 0713, they heard a loud "whoosh" and felt a push followed by a mild bounce. The balloon immediately began to rise. Both crew members looked up through a porthole and saw that the bottom of the main gas cell, or diaphragm, had ruptured. The PIC estimated that 62 percent of the diaphragm was open, and the pilot controlled gas valve in the top of the gas cell could be seen. Radar data indicated that the balloon rose to approximately 32,500 feet. As the PIC declared an emergency, the SIC began "valving off" helium gas to establish a 300 to 500 fpm rate of descent. Both crewmembers said they heard continual "pops, rips, and tearing" as the balloon descended. At approximately 18,000 feet msl, the crew heard a particularly loud noise, and the balloon began to rotate.

At approximately 12,000 feet msl, the crew depressurized the gondola and photographed the ruptured diaphragm. T

Sources:

NTSB id 20001211X09419


Revision history:

Date/timeContributorUpdates
21-Dec-2016 19:26 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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