# NTSB LAX90FA111: American AA-1, N5655L, Borego Springs, CA, March 10, 1990

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: March 10, 1990, 15:16 local (23:16 UTC)
- Place: Borego Springs, CA
- Coordinates: 33.169952, -116.270011 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.1700&lon=-116.2700&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious
- Status: Completed, report June 2, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 26618
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90FA111
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26618/pdf
- Page: https://openairdocs.org/ntsb/LAX90FA111

## Probable cause

IMPROPER IN-FLIGHT PLANNING/DECISION BY THE PILOT, AND HIS FAILURE TO MAINTAIN SUFFICIENT AIRSPEED AND ALTITUDE, WHICH RESULTED IN A STALL/MUSH INTO RISING MOUNTAINOUS TERRAIN.  FACTORS RELATED TO THE ACCIDENT WERE:  THE TERRAIN AND WEATHER CONDITIONS, AND FAILURE OF THE ENGINE TO PROVIDE FULL POWER, DUE TO IMPROPER MAINTENANCE AND SUBSEQUENT WEAR OF THE CAM LOBES & TAPPETS.

## Sequence of events

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

- In flight collision with terrain/water, climb
  - in-flight planning/decision - improper, pilot in command (cause)
  - terrain condition - high terrain (contributing factor)
  - terrain condition - rising (contributing factor)
  - weather condition - high density altitude (contributing factor)
  - weather condition - downdraft (contributing factor)
  - maintenance,overhaul,major - improper, company maintenance personnel (contributing factor)
  - engine assembly,camshaft - worn (contributing factor)
  - engine assembly,rocker arm/tappet - worn (contributing factor)
  - aircraft performance,climb capability - other (contributing factor)
  - proper altitude - not maintained, pilot in command (cause)
  - airspeed - not maintained, pilot in command (cause)
  - stall/mush - inadvertent, pilot in command (cause)
  - terrain condition - mountainous/hilly (contributing factor)

## Analysis

THE ACFT HAD FLOWN 228 HRS, SINCE THE ENG WAS OVERHAULED. THE OVERHAUL WAS DONE BY THE OWNERS & SIGNED OFF BY AN A & P MECH. DRG THE OVERHAUL, THE CAM SHAFT WAS GROUND & THE TAPPETS RESURFACED. THE LYCOMING O/H MANUAL STATED THAT IF THE CAM SHAFT WAS REPLACED OR REGROUND, NEW TAPPETS MUST BE INSTALLED TO PREVENT SEVERE WEAR & SPALLING OF THE CAM LOBES & TAPPET BODIES. EXAM OF THE ENG REVEALED THAT THE CAM LOBES & TAPPETS FOR THE #1 & #2 CYLS WERE SEVERELY SPALLED & WORN DOWN TO ABOUT HALF THE NORMAL PROFILE. LYC TECH REPS SAID THE CAM LOBE WEAR WOULD CHANGE THE DURATION & AMOUNT OF VALVE ACTION, REDUCING THE POWER OUTPUT ABILITY. OTR DISCREPANCIES WERE FOUND DURING THE EXAM OF THE ENG. AFTER DEPG, THE ACFT CLIMBED TOWARD THE MTNS. THE TRRN RISE WAS ABOUT 470 FT/MI & THE ACFT WAS CAPABLE OF CLIMBING AT ABOUT 350 FT/MI. WITNESSES SAW THE ACFT APCH THE MTN RIDGE LOW & SLOW, THEN TURN LEFT AS IT BEGAN A DSCNT TO THE GND. HIGH WINDS WERE BLOWING ACROSS THE RIDGE AT THE TIME & CLOUDS TOPPED THE MTNS.

## Aircraft

- Registration: [N5655L](https://openairdocs.org/deregistered/N5655L-1993-07-29), registration cancelled 1993-07-29, S/N AA10055 (OpenAirDocs)
- Reported make and model: AMERICAN AA-1
- Registry model: [American AA-1](https://openairdocs.org/model/american-aa-1) (registry code 0630610) (OpenAirDocs)
- Category: Airplane
- Serial number: AA1-0055
- Engines: LYCOMING O-235-C2C 108 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Puffer, Gene L.
- Departed: L08, BOREGO SPRINGS, CA
- Destination: SEE, EL CAJON, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 32; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; flight hours: 1,201 total, 100 in this make and model, 1,052 as pilot in command, 55 in the last 90 days, 22 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 320° at 10 knots, gusting 15
- Visibility: 50 statute miles
- Lowest ceiling: 1,500 ft broken
- 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 19900310003789A](https://openairdocs.org/incident/19900310003789A), Mar 10, 1990: Gulstm AA1, Borrego Springs, CA, Substantial damage. Proceeded toward mountain ridge unable clear ridge due gross weight and downdrafts. Engine was in poor condition.

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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