LAX99LA221 · Cessna 172M
Plus One Flyers Cessna 172M · Accident: airframe, component or system failure en route
From Montgomery-Gibbs Executive Airport (MYF) to an unrecorded destination
Event
- NTSB case
- LAX99LA221
- 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
Cessna 172M
- Aircraft type
- Cessna 172
- Category
- Airplane
- 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
- N61560
- Operator
- Plus One Flyers
- Onboard fatalities
- Unknown
- Route
- From Montgomery-Gibbs Executive Airport (MYF)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
- 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
- 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
- Destroyed
Cause areas
- Electrical system › Failure, total
- Electrical system, alternator › Unapproved part
- Electrical system, voltage regulator › Loose
- Other maintenance personnel › Maintenance, installation, improper
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During a practice instrument approach on a dark night, the aircraft began losing electrical power. The airplane was over a low cloud layer and the pilot cancelled his IFR clearance, informed ATC that he was losing electrical power and that he would fly back to home base under visual flight rules. He then flew in a southerly direction, following roads until he decided that he had flown far enough to locate his home airport. He was unable to locate the airport, made a 180-degree turn in an attempt to locate another airport, and found that he was unsure of his position. He elected to land on a large well-lit parking lot and collided with concrete barriers during the landing roll. An automotive alternator was found installed on the airplane, with a nonapproved support bracket that allowed for pulley misalignment, slack belt tension, and excessive vibration. The voltage regulator, alternator, and associated wiring harnesses were removed for functional testing. The voltage regulator and the alternator as separate units passed functional tests. The power input connector on the regulator fit loosely and allowed an intermittent electrical connection. Failure of the connection would allow the alternator to cease operating. A month prior to the accident, in response to pilot reports of intermittent low system output, a mechanic removed the alternator for repair. The automotive shop that performed the work found the unit had an acceptable voltage output, but the amperage was low. A diode in the bridge rectifier was replaced and the mechanic reinstalled the alternator on the engine. The mechanic said the alternator had been on the airplane for several years and 'it never occurred to [him] to check the Type Certificate Data Sheet' to ensure the alternator was approved for airplanes.
Probable cause
The mechanic's improper installation of nonapproved automotive electrical system parts, and his failure to ensure that all electrical connections were secure during the reinstallation, which resulted in the failure of the electrical system. The pilot's becoming lost and disoriented during the subsequent attempt to find an airport on the dark night flight was a factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX99LA221
- Event ID
- 20001212X19032
- Case number
- LAX99LA221
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1999-06-21.
- API snapshot SHA-256: f4e599825aa55e105118c67d1640a2bd9248b0dae82f2e7dbd00fead5bbb2b2f; retrieved 2026-09-21T10:59:05.678Z.