NTSB Identification: CHI99IA136.
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Scheduled 14 CFR MIDWEST EXPRESS AIRLINES
Incident occurred Friday, April 09, 1999 in DUBUQUE, IA
Probable Cause Approval Date: 05/09/2001
Aircraft: McDonnell Douglas DC-9-32, registration: N205ME
Injuries: 91 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
The airplane departed in rain with a surface temperature of 39 degrees Fahrenheit. Upon reaching cruise altitude, the flight crew discovered that the elevator control '...was found to be frozen and would not move.' The pilot said that the aircraft was flown using primary and alternate trim until a descent was made to 'warmer air', and the '... elevator thawed out...' and normal control was regained. An inspection of the aircraft after the incident failed to reveal any anomalies with respect or the aircraft or aircraft systems. On two other occasions, Midwest Express Airlines (MWEA) DC9 aircraft have experienced elevator control difficulties. On these occurrences, the aircraft departed in rain with temperatures of 46 degrees Fahrenheit and 39 degrees Fahrenheit respectively. On one of the occurrences, MWEA maintenance personnel found ice accretions in the elevator control bay of the vertical stabilizer.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: the frozen elevator control. Factors to the incident were the rain and the low temperature. Full narrative available
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