Event Details


Title:Loss of elevator control, Douglas DC-9-14, March 21, 1999
Micro summary:This Douglas DC-9-14 experienced loss of elevator control while in cruise flight.
Event Time:1999-03-21 at 1945 CST
File Name:1999-03-21-US.pdf
Publishing Agency:National Transportation Safety Board (NTSB)
Publishing Country:USA
Report number:CHI99IA115
Pages:5
Site of event:Grand Rapids, MI
Departure:Newark Liberty International Airport, Newark & Elizabeth, New Jersey, USA
Destination:General Mitchell International Airport, Milwaukee, Wisconsin, USA
Airplane Type(s):Douglas DC-9-14
Flight Phase:Cruise
Registration(s):N600ME
Operator(s):Midwest Express Airlines
Type of flight:Revenue
Occupants:64
Fatalities:0
Serious Injuries:0
Minor/Non-Injured:64
Other Injuries:0
Executive Summary:

NTSB short summary:

the frozen elevator control. Factors were the rain and the low temperatures.

NTSB synopsis:

On two separate flights, the flight crews determined that the elevator would not respond to control input. During the first occurrence, the flight crew continued to fly the airplane using pitch trim and descended to a lower altitude where elevator control returned. During the second occurrence, the flight crew applied elevator backpressure until the elevator '...bump[ed} free and control was restored.' After the first occurrence, maintenance personnel found ice accretions in the elevator control bay of the vertical stabilizer. They also found debris obstructing the drain holes in this area. Maintenance personnel were unable to find any anomalies after the second occurrence. On both occasions, the airplane departed in rain showers with surface temperatures of 46 degrees (F) and 39 degrees (F) respectively.

NTSB factual narrative text:

On March 21, 1999, at 1945 central standard time (cst), a McDonnell Douglas DC-9-14, N600ME, operated by Midwest Express Airlines (MWEA), Inc., experienced a loss of elevator control while in cruise flight over Grand Rapids, Michigan. The 14 CFR Part 121 flight departed Newark International Airport (EWR), Newark, New Jersey, en route to General Mitchell International Airport (MKE), Milwaukee, Wisconsin. The flight crew piloted the aircraft using the elevator trim system until regaining elevator control after descent. The airplane landed at General Mitchell International Airport without further incident. There were no reported injuries to the four-person crew or to the 60 passengers.

Weather at the departure airport, approximately 19 minutes prior to departure, was reported as heavy rain showers and mist, and a temperature of 46 degrees (F). Upon arrival, at MKE, MWEA maintenance personnel inspected the aircraft and found ice accretions in the elevator control bay of the vertical stabilizer. Debris was also found covering the drainage holes within this bay. No other anomalies were detected with respect to the incident aircraft. No ice was found in any area that would have prevented movement of the elevator.

On April 9, 1999, approximately 0745 cst, the same airplane, N600ME, experienced a similar occurrence while in cruise flight. The aircraft had departed MKE en route to EWR. The weather, at MKE, at the departure time, was reported as rain showers and mist, and a temperature of 39 degrees (F). After leveling off at 29,000 feet altitude, the pilots determined that the elevator control would not respond to control inputs. The captain stated, in a written report, that he "applied more and more elevator backpressure until I [he] finally felt [the] elevator control 'bump' free and control was restored." The flight continued to EWR with no further difficulties.

After the April 9, 1999 occurrence, MWEA maintenance personnel inspected the aircraft and no anomalies were noted with respect to the elevator control difficulties.
Learning Keywords:Operations - Icing
Systems - Elevator, Stabilizer, Rudder, Ailerons
Systems - Flight Control System
Close match:Pitch control problems, Boeing 767-300, March 27, 2001
Frozen elevator control, Douglas DC-9-32, April 9, 1999
Frozen aileron cable, Boeing 767-222, June 7, 2000
Frozen elevators, McDonnell Douglas MD-82, February 5, 1999
Flight control system problems following icing, Avro 146-RJ100 and others, G-JEAV, January 17, 2006
Flight control difficulties, McDonnell Douglas MD-11-C, I-DUPA, January 14, 2003

 




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