Aviation Accident Summaries

Aviation Accident Summary LAX98LA025

DESERT CENTER, CA, USA

Aircraft #1

N153JC

Ciernia GLASAIR-III

Analysis

The aircraft is equipped with dual electronic ignition instead of magnetos. After leveling off on top, the pilot noticed that his panel indicated a loss of electrical power. After the battery was depleted, the engine quit and the aircraft descended into IMC conditions. After breaking out, he initiated a forced landing. The aircraft struck a berm and slid to a stop. The pilot stated that the alternator switch was on and that the alternator out warning light had not illuminated prior to his electrical loss. After recovery, the batteries were charged and the engine was started. When the alternator switch was moved to the off position, the alternator out warning light did not illuminate. The continuity of the light bulb was confirmed. The light socket failed a similar continuity check. The flight instructor who checked the pilot out in the aircraft reported that he did not always use the checklist and had forgotten to turn the alternator switch on before starting on several occasions.

Factual Information

On October 11, 1997, at 1315 hours Pacific daylight time, an experimental Ciernia Glasair-III, N153JC, made a forced landing near Desert Center, California, following a loss of power. The aircraft sustained substantial damage; however, the pilot, the sole occupant, was not injured. The aircraft was being operated as a personal flight by the pilot/owner when the accident occurred. The flight originated in Mesa, Arizona, at 1145. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he had been cruising at 10,500 feet msl when he encountered IMC conditions. He initiated a climb to 16,500 feet in order to maintain VFR. About 30 to 60 seconds after leveling off at the higher altitude, he looked at the panel and noticed that he no longer had any indications of electrical power. After the remaining battery charge was depleted, the engine quit and the aircraft descended into IMC conditions. After descending into the cloud layer, the instrument rated pilot maintained a wings level attitude with reference to the attitude indicator, until breaking out about 3,000 to 4,000 feet agl. He saw Eagle Mountain Airport toward the left front of the aircraft, but concluded that he was not within gliding distance of the runway. He then selected a dirt road and initiated a wheels up, forced landing. As he approached touchdown, the pilot noticed that the road had berms on either side that he had not seen from the air. During touchdown, the aircraft's left wing struck a berm and the aircraft yawed left. The aircraft slid to a stop with the tail on the right berm and the nose at the base of the berm on the left. The pilot was able to shut down the aircraft and exit without difficulty. The before starting checklist specifies that the alternator switch be turned on prior to starting the engine. The pilot stated that the alternator switch was on and that the alternator out warning light did not illuminate at any time prior to his loss of engine power. A postaccident inspection of the aircraft by a Federal Aviation Administration (FAA) airworthiness inspector revealed that the aircraft was equipped with a dual electronic ignition system that does not utilize magnetos. The damaged aircraft propeller was replaced and fuel was introduced to the engine through the fuel line. The batteries were reconnected and their voltage was checked with a panel mounted voltmeter. The check showed that battery No. 1 registered 10.4 volts, while battery No. 2 registered 10.7 volts. When the starter was engaged, the engine did not respond. A battery charger was connected to both batteries in parallel and remained in place until the voltage of both batteries exceeded 12 volts. The starter was engaged and the engine started and ran. With the alternator switch in the on position, the voltmeter read 12.6 volts. However, when the alternator switch was moved to the off position, the discharge light illuminated but the alternator out warning light did not illuminate. The alternator out light bulb was removed from the panel and its electrical continuity was confirmed using a multimeter. The alternator out light socket failed to show continuity during a similar check with the engine running and the alternator switch in the off position. The flight instructor, who had previously checked the pilot out in the aircraft, reported that they had flown together on 5 flights, totaling 10.2 hours. During those flights, he said the pilot did not always use the checklist, and forgot to turn the alternator switch to the on position before starting on several occasions.

Probable Cause and Findings

A loss of engine power due to the eventual loss of electrical power which resulted from the pilot's failure to ensure the alternator switch was on as specified in the before starting checklist. The inoperative alternator out warning light was a factor in this accident.

 

Source: NTSB Aviation Accident Database

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