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LAX90LA277 · Thunder and Colt AX9-140 SLI AX9-140 SL

7 Aug 1990 · Napa, CA, United States

Thunder and Colt AX9-140 SLI AX9-140 SL · Accident: in flight encounter with weather en route

From No airport to No airport

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Event

NTSB case
LAX90LA277
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
Accident
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

Thunder and Colt AX9-140 SLI AX9-140 SL

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
N9112R
Operator
Unknown
Onboard fatalities
Unknown
Route
From No airportTo No airport
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
En route · cruise
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
In flight encounter with weather
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft performance, climb capability › Exceeded
  • Weather condition › Microburst/dry

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

SEVENTEEN BALLOONS LAUNCHED FROM VARIOUS LOCATIONS AROUND THE NAPA VALLEY FOR LOCAL SIGHTSEEING FLIGHTS. STATEMENTS FROM PILOTS, PASSENGERS AND GROUND WITNESSES SAID THAT WHILE THE BALLOONS WERE IN NORMAL DRIFTING FLIGHT A MICROBURST LIKE CONDITION SUDDENLY OCCURRED WHICH AFFECTED ALL OF THE BALLOONS. THE WEATHER PHENOMENA ENCOUNTERED INCLUDED STRONG GUSTING SURFACE AND ALOFT WINDS IN ADDITION TO SEVERE DOWN DRAFTS. THE BALLOONS WERE RAPIDLY FORCED TOWARD THE GROUND AS THEIR GROUND SPEED INCREASED RADICALLY. THE PILOTS OF SEVERAL BALLOONS REPORTED THAT THE SHAPES OF THEIR BALLOON ENVELOPES WERE SEVERELY DISTORTED BY THE SUDDEN MOVEMENT OF THE AIRMASS. EIGHT OF THE 17 BALLOONS ATTEMPTED FORCED LANDINGS. FOUR OF THE BALLOONS SUCCESSFULLY LANDED. THE OTHER FOUR BALLOONS COLLIDED WITH OBSTRUCTIONS AND THE GROUND DURING THE ATTEMPTED LANDINGS. AT THE TIME OF THE INCIDENT, A LARGE THUNDERSTORM WAS REPORTED 30 MILES TO THE NORTH.

Probable cause

FLIGHT'S ENCOUNTER WITH A PROBABLE MICROBURST WEATHER PHENOMENA WITH DOWN DRAFTS AND WINDS BEYOND THE PERFORMANCE CAPABILITY OF THE BALLOON.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX90LA277
Event ID
20001212X24046
Case number
LAX90LA277
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: e018f537e09db3a7a001337111b3619bd8d7888df5169541ac79135a11a9c03d; retrieved 2026-09-21T15:38:36.983Z.