Balloon Works FIREFLY 11 accident near Cave Creek, Arizona, August 19, 1999
On August 19, 1999 at about 2:10 pm local time, a Balloon Works FIREFLY 11, registered N7021U, suffered minor damage in an accident near Cave Creek, Arizona. It was a flight of an unrecorded kind under general aviation rules (Part 91). 1 person was seriously injured and 4 people had minor injuries; 8 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
An unforecast encounter with a low level microburst that resulted in a distortion of the balloon envelope, an excessive outflow of hot air (loss of lift), creating an excessive rate of descent that was beyond the performance capability of the balloon to recover in the altitude available. The failure of a passenger to follow the emergency procedures directives of the pilot was a factor in this accident.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 19, 1999 · about 2:10 pm local time
- Place
- Cave Creek, Arizona · map
- Type
- Accident
- Injuries
- 1 person was seriously injured and 4 people had minor injuries; 8 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Balloon Works FIREFLY 11
- Registration
- N7021U · no longer on the register · serial F11-006
- Damage
- Minor damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
While attempting a high wind landing, the balloon hit hard and one passenger sustained serious injuries. The pilot checked weather prior to departure, and said that at 0610, the weather was mostly cloudy with surface winds from the south at 3 to 5 mph. About 0635, the nearby Deer Valley airport ATCT told the pilot that surface winds were 12 knots from 220 degrees. In addition, another company pilot told him by radio that surface winds in his location were now 25 mph. The pilot's ground crew also confirmed that surface winds had increased substantially. The pilot said that he was 3,000 feet msl when the change in wind velocity was reported, and he selected an alternate landing site and briefed his passengers on high wind landing procedures. The approach was initiated at a descent rate of 700 fpm. During this time he told the two standing passengers to sit down because they would be experiencing a very rough landing. After descending through 500 feet agl at 700 fpm, the balloon's vertical sink rate suddenly increased substantially. He said this encounter had caused distortion in the envelope that resulted in the envelope losing hot air (lift), and increasing his rate of descent. His attempt to slow the descent in the time remaining was unsuccessful and the balloon landed short of the intended site, rebounded into the air, and then skidded about 100 yards before coming to a stop with the carriage lying on its side. Another balloon pilot, who saw the landing, said that the balloon appeared to have encountered a sudden microburst that resulted in an inadvertent hard landing. Other witnesses described the final descent as rapid, and noted that the envelope was distorted (flattened) downward as if the balloon was being pushed down. According to the FAA approved performance data sheet, terminal velocity (Vt) of the balloon under maximum gross weight conditions is 1,200 fpm with a recovery time to equilibrium 90 seconds, and altitude lost during recovery (from application of burner to equilibrium) to be 1,000 feet. The POH states that should weather conditions deteriorate while in flight, the pilot should land immediately, and "to risk damage if necessary to land while the flight is still under control." The manufacturer reported that the maximum demonstrated wind speed at landing during certification testing was 7 knots.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: balloon
- Flight time: 4,011 hours in all; 57 in this make and model; 55 in the last 90 days; 24 in the last 30 days; 3,970 as pilot in command; 200 on instruments
- Medical certificate: None
- Seat: ctr
The aircraft
- Airframe total time: 98 hours
- Last inspection: annual inspection, August 17, 1999; 2 hours since
- Maximum gross weight: 3,940 lb
- Seats: 15
- Landing gear: fixed
- Engine: (type not recorded); 0 hours total
- Operator: Hot Air Expeditions, INC.
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 220° at 7 knots
- Visibility: 40 statute miles
- Sky: overcast at 20,000 ft; not recorded
- Temperature: 190°F (88°C), dew point 131°F (55°C)
- Altimeter: 29.00 inHg
- Observation at 1:50 pm from SDL, 12 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 4 | 7 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N7021U the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.