NTSB Identification: ATL93MA068.
The docket is stored on NTSB microfiche number 50563.
Accident occurred Thursday, April 01, 1993 in BLOUNTVILLE, TN
Probable Cause Approval Date: 03/16/1994
Aircraft: Fairchild SA227-TT, registration: N500AK
Injuries: 4 Fatal.

NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.

N500AK ENCOUNTERED ICING IN FLIGHT BEFORE START OF ILS APPROACH. RADAR DATA SHOWED THAT BEFORE REACHING OUTER MARKER, IT SLOWED IN A MANNER THAT WAS CONSISTENT WITH A POWER REDUCTION (OR PARTIAL LOSS OF POWER), THEN IT ENTERED A STEEP DESCENT & CRASHED. EXAMINATION REVEALED ENGINES WERE NOT OPERATING AT IMPACT & THAT PROPELLERS HAD BEEN FEATHERED. NO PREIMPACT PART FAILURE OR MALFUNCTION OF ENGINES, PROPELLERS OR ANTI-ICE SYSTEM WAS FOUND. THERE WAS EVIDENCE THAT ENGINE INLET ANTI-ICE ANNUNCIATOR LIGHTS & STABILITY AUGMENTATION SYSTEM (SAS) FAULT WARNING LIGHT WERE ILLUMINATED DURING IMPACT. THE ENGINE MANUFACTURER REPORTED THAT FLAMEOUTS HAD OCCURRED IN OTHER AIRCRAFT, DURING OR FOLLOWING OPERATION IN ICING CONDITIONS, SOMETIMES AFTER DESCENT INTO WARMER AIR. FLIGHT MANUAL NOTED THAT IF ICING WAS ENCOUNTERED WITH ANTI-ICE SYSTEM OFF, SELECT CONTINUOUS IGNITION & THEN SELECT ENGINE & PROPELLER HEAT (1 ENGINE AT A TIME, ENSURING FIRST ENGINE WAS OPERATING SATISFACTORILY BEFORE SELECTING SECOND ENGINE) & ENGAGE SAS HEAT.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

FAILURE OF THE PILOT TO FOLLOW PROCEDURES CONCERNING USE OF THE ENGINE INLET ANTI-ICE SYSTEM AND/OR CONTINUOUS IGNITION WHILE OPERATING IN ICING CONDITIONS, WHICH RESULTED IN PROBABLE ICE INGESTION AND LOSS OF ENGINE POWER; AND THE PILOT'S FAILURE TO MAINTAIN SUFFICIENT AIRSPEED WHILE COPING WITH THE ENGINE PROBLEM, WHICH RESULTED IN A STALL. FACTORS RELATED TO THE ACCIDENT WERE: DARKNESS, ICING CONDITIONS, AND ENGINE INLET (NACELLE) ICE.

Full narrative available

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