DEN99IA154 · Balloon Works FIREFLY 9
Balloon Works FIREFLY 9 · Incident: airframe, component or system failure during landing
From CO (no airport) to an unrecorded destination
Event
- NTSB case
- DEN99IA154
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Incident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Balloon Works FIREFLY 9
- Aircraft type
- Balloon Works FIREFLY 9
- Category
- Balloon
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N2570E
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From CO (no airport)To not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Landing · flare/touchdown
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Balloon equipment, control system › Burned
- Balloon equipment, control system › Failure, total
- Reason for occurrence undetermined
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
As he approached the touchdown point, the pilot flared the balloon and pulled the deflation line. The line broke and fell into the basket. The pilot was unable to deflate the balloon because the line had broken inside the envelope near the parachute harness. The ground crew secured the balloon long enough for the passengers to exit, then the wind dragged it across the ground. Holes were cut in the middle portion of the envelope to gain access to the deflation valve, and the balloon was deflated. Examination of the deflation line by NTSB's Materials Laboratory disclosed glazing damage to the outer cover, typical of heat damage. According to the manufacturer, the Kevlar braided inner core chars at 890 degrees F. The nylon or polyester braided outer covering has a stick point of 430 degrees F. and a melting point of 492 degrees F. A new line has a nominal strength of 4,000 pounds.
Probable cause
Total failure of the deflation line due to heat damage (as evidenced by glazing), most likely caused by the improper use of the flight controls (burner system) by person(s) unknown.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN99IA154
- Event ID
- 20001212X19481
- Case number
- DEN99IA154
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: c611eedaac28f26f808829ac26c1e91861023ba17b5cdee7c7a4c1b303a60bdf; retrieved 2026-09-22T14:18:58.919Z.