# NTSB LAX90LA278: Aerostar S-66A, N3595M, Napa, CA, August 7, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: August 7, 1990, 07:44 local (14:44 UTC)
- Place: Napa, CA
- Coordinates: 38.550559, -122.150543 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.5506&lon=-122.1505&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 3 minor, 5 uninjured
- Status: Completed, report November 9, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26885
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90LA278
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26885/pdf
- Page: https://openairdocs.org/ntsb/LAX90LA278

## Probable cause

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

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight encounter with weather, cruise
  - weather condition - microburst/dry (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - aircraft performance,climb capability - exceeded (cause)
  - terrain condition - high obstruction(s) (contributing factor)

## Analysis

SEVENTEEN BALLOONS LAUNCHED FROM VARIOUS LOCATIONS AROUND THE NAPA VALLEY FOR LOCAL SIGHTSEEING FLIGHTS. STATMENTS FROM PILOTS, PASSENGERS AND GROUND WITNEESES 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 PILOT OF SEVERAL BALLOONS. REPORTED THAT THE SHAPES OF THE BALLOON ENVELOPES WERE SEVERELY DISTORTED BY THE SUDDEN MOVEMENT OF THE AIRMASS. EIGHT OF THE 17 BALLOONS ATTEMPTED FORCED LANDINGS.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.

## Aircraft

- Registration: [N3595M](https://openairdocs.org/deregistered/N3595M-2017-05-31), registration cancelled 2017-05-31, S/N S66A-3032, built 1989 (OpenAirDocs)
- Reported make and model: Aerostar S-66A
- Registry model: [Aerostar International RAVEN S-66A](https://openairdocs.org/model/aerostar-international-raven-s-66a) (registry code 7486067) (OpenAirDocs)
- Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs)
- Category: Balloon
- Serial number: S66A 3032
- Engines: unknown
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Balloon About The Napa Valley
- Departed: NONE
- Destination: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial; flight hours: 2,289 total, 254 in this make and model, 2,220 as pilot in command, 54 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 20 knots, gusting 30
- Visibility: 30 statute miles
- Lowest ceiling: 30,000 ft overcast
- Temperature: 70 °F, dew point 57 °F
- Altimeter: 29.00 inHg
- Observed at: APC

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19900807030949A](https://openairdocs.org/incident/19900807030949A), Aug 7, 1990: Raven S66A, Napa, CA, Destroyed. Encountered micro burst severe gusty winds. Forced to ground. Impact injured passengers. Thunderstorm in area.

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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