NTSB Identification: ATL88FA191.
The docket is stored on NTSB microfiche number 37492.
Accident occurred Thursday, June 09, 1988 in KNOXVILLE, TN
Probable Cause Approval Date: 11/16/1989
Aircraft: CESSNA 421B, registration: N700SC
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

DURING AN IFR FLT AT FL170, THE PLT RPTED AIRFRAME ICING AND REQUESTED A HIGHER ALT. THE PLT CLIMBED TO FL210 WHERE HE STARTED A DESCENT AND RPTED LOSS OF MANIFOLD PRESSURE IN THE LEFT ENGINE. THE PLT INDICATED THAT WX WAS IN HIS FLT PATH AND DESCENT WAS REQUIRED TO AVOID ICING. 90 SECONDS LATER THE PLT XMITTED '...LOSING IT...'. RADAR DATA INDICATED ACFT HAD AN INFLT BREAKUP AT APPROXIMATELY 17,000' MSL. THERE WAS NO EVIDENCE OF MECHANICAL OR STRUCTURAL MALFUNCTION PRIOR TO THE BREAKUP. THE ACFT DID NOT HAVE A COMPLETE CURRENT ANNUAL AND DE-ICE EQUIPMENT WAS INOP. THE PLT HAD NO ACTUAL INST EXPERIENCE AND WAS NOT CERTIFIED FOR MULTIENGINE IFR FLT. THE PLT HAD A MEDICAL HISTORY OF ANXIETY ATTACKS AND HAD BEEN TAKING PRESCRIPTION MEDICATION, XANAX AND TOFRANIL, FOR APPROX THREE YEARS PRIOR TO THE ACCIDENT. THE BLOOD CONTAINED 1.2 MCG/ML OF IMIPRAMINE(TOFRANIL) AND 2.6 MCG/ML DESIPRAMINE(METABOLITE OF TOFRANIL). XANAX (ALPRAZOLAM) WAS NOT RPTD IN BLOOD TOX. THESE DRUGS HAVE BEEN KNOWN TO PRODUCE SIDE EFFECTS THAT INCLUDE POOR JUDGEMENT.

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

DESIGN STRESS LIMITS OF AIRCRAFT..EXCEEDED..PILOT IN COMMAND

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

IN-FLIGHT PLANNING/DECISION..POOR..PILOT IN COMMAND

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

IMPAIRMENT(DRUGS)..PILOT IN COMMAND

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

FLIGHT INTO KNOWN ADVERSE WEATHER..INTENTIONAL..PILOT IN COMMAND


Contributing Factors

WEATHER CONDITION..THUNDERSTORM




Contributing Factors

OPERATION WITH KNOWN DEFICIENCIES IN EQUIPMENT..PERFORMED..PILOT IN COMMAND



Contributing Factors

WEATHER CONDITION..ICING CONDITIONS


Contributing Factors

FLIGHT CONTROL SURFACES/ATTACHMENTS..ICE


Contributing Factors

WEATHER CONDITION..RAIN


Contributing Factors

WEATHER CONDITION..TURBULENCE


Contributing Factors

LACK OF TOTAL INSTRUMENT TIME..PILOT IN COMMAND


Contributing Factors

OPERATION WITH KNOWN DEFICIENCIES IN EQUIPMENT..PERFORMED..PILOT IN COMMAND

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