ASN Wikibase Occurrence # 358013
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| Date: | Friday 17 November 1995 |
| Time: | 09:45 LT |
| Type: |  Saab 340B |
| Owner/operator: | Simmons Airlines |
| Registration: | N344SB |
| MSN: | 340B-344 |
| Total airframe hrs: | 4543 hours |
| Engine model: | GE CT7-9B |
| Fatalities: | Fatalities: 0 / Occupants: 33 |
| Aircraft damage: | None |
| Category: | Serious incident |
| Location: | Corsicana, TX -
 United States of America
|
| Phase: | Unknown |
| Nature: | Unknown |
| Departure airport: | Corpus Christi, TX (CRP |
| Dallas/ft Worth, TX | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
During descent, after exiting light icing conditions, the left engine lost power, & power fluctuations of the right engine were noted. The flightcrew declared an emergency, diverted to the nearest airport, & made an uneventful landing. There were indications of engine ice ingestion, but no engine damage. During ground runups, the right engine performed normally. The left engine ran normally, except its auto-ignition & overspeed protection were inoperative due to an open fuse in the Digital Electronic Control Unit (DECU). The open fuse would have prevented an automatic relight after a flameout. The Saab 340 fleet has a history of power losses associated with in-flight icing, dating back to 1985. The manufacturer (Saab) had determined that ice/slush could accumulate on the rear wall of the inlet protective device (bird catcher) & shed from the 'splitter lip' into the engine airflow path. As a preventive measure, Saab had developed an auto-ignition system to provide automatic relighting of the engine. Also, Saab was testing an improved heating system to prevent ice/slush from accumulating on the splitter lip. Title 14 CFR Part 25 requires that airplanes be designed so that engine inlet ice that would adversely affect engine operation cannot accumulate. During flight tests with the left engine inoperative & the propeller synchrophaser engaged, multiple power fluctuations of the right engine occurred. Instructions to turn the synchrophaser 'off' were not included in the engine failure checklist.
Probable Cause: Total loss of power in the left engine from ice ingestion; and failure of the left-engine auto-relight system caused by an open fuse in the Digital Electronic Control Unit (DECU), which prevented an automatic relight of the left engine. Factors relating to the incident were: inadequate design of the engine air inlet anti-ice system, which allowed ice/slush accumulation; inadequate action by the FAA to ensure compliance with certification requirements regarding inlet ice accumulation; and an inadequate procedure in the flight manual concerning use of the engine synchrophaser during single-engine operation.
Accident investigation:
 |
|
Sources:
NTSB FTW96IA045
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 14-Mar-2024 09:05 | ASN Update Bot | Added |
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