# NTSB LAX91LA038: Aerostar S-77A, N3605T, Phoenix, AZ, November 24, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: November 24, 1990, 07:30 local (15:30 UTC)
- Place: Phoenix, AZ
- Coordinates: 33.679782, -112.090148 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.6798&lon=-112.0901&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious, 5 minor
- Status: Completed, report April 13, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 27065
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA038
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27065/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA038

## Probable cause

STRENGTH DEGRADATION OF THE KEVLAR SUSPENSION CABLES, DUE TO PREVIOUS HEAT DAMAGE.  FACTORS RELATED TO THE ACCIDENT WERE:  FAILURE OF THE QUICK RELEASE LINE TO RELEASE, AND SUSCEPTIBILITY OF KEVLAR SUSPENSION CABLES TO HEAT.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff
  - balloon equipment - inoperative (contributing factor)
  - balloon equipment,suspension system/cables - failure,total (contributing factor)
  - acft/equip,inadequate standard/requirement, manufacturer (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - rough/uneven

## Analysis

WHILE BOARDING PSNL FOR A LAUNCH, THE BALLOON (BLN) WAS INFLATED & TETHERED TO A VEHICLE WITH A QUICK RELEASE LINE. WINDS AT THE TIME WERE ESTD TO BE ABT 7 KTS & SLIGHTLY GUSTY. DRG THE LAUNCH, THE PLT ADDED HEAT TO TAKEOFF & SIGNALED FOR A RELEASE, BUT THE QUICK RELEASE LINE FAILED TO RELEASE. THE BLN SETTLED TO THE GND & 'BOBBED' UP & DWN 2 TIMES. THE PLT RPRTD THAT AT THE HEIGHT OF A BOUNCE (ABT 6 TO 10 FT), ALL 28 OF THE ADVANCED FIBER TECHNOLOGY (AFT) KEVLAR SUSPENSION CABLES FAILED. THE BASKET FELL TO THE GND & THE ENVELOPE ROSE TO ABT 500 TO 700 FT, THOUGH THE RED LINE STAYED ATTACHED TO THE BASKET & OPENED THE DEFLATION PORT; 2 OF THE 7 OCCUPANTS RCVD SERIOUS INJURIES. AN EXAM REVEALED STRENGTH DEGRADATION OF THE KEVLAR CABLES DUE TO HEAT EXPOSURE. THE BLN HAD 240 HRS OF FLT TIME. STRENGTH LOSS WAS FND IN SOME AFT/KEVLAR CABLES OF OTHER BLNS. ON 11/28/90, AEROSTAR INTL SVC BULLETIN #129 WAS ISSUED TO RETROFIT ALL S-66A & S-77A BNS WITH STEEL CABLES.

## Aircraft

- Registration: [N3605T](https://openairdocs.org/deregistered/N3605T-1992-11-05), registration cancelled 1992-11-05, S/N S77A3011 (OpenAirDocs)
- Reported make and model: Aerostar S-77A
- Registry model: [Aerostar International S-77A](https://openairdocs.org/model/aerostar-international-s-77a) (registry code 7487077) (OpenAirDocs)
- Category: Balloon
- Serial number: S77A-3011
- Engines: unknown
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Unicorn Balloon Co.
- Destination: NONE

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; flight hours: 2,132 total, 1,100 in this make and model, 2,091 as pilot in command, 71 in the last 90 days, 26 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 60° at 7 knots, gusting 10
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## 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 19901124051709A](https://openairdocs.org/incident/19901124051709A), Nov 24, 1990: Raven S77A, Phoenix, AZ, Substantial damage. Cord on tethered balloon failed release. Caused bounce. Support cables failed. Dropped basket. Overdue maintenance.

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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