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Safety Recommendation Details

Safety Recommendation A-99-026
Details
Synopsis: On 9/8/94, about 1903:23 eastern daylight time, USAir (now US Airways) flight 427, a Boeing 737-3B7 (737-300), N513AU, crashed while maneuvering to land at Pittsburgh Int'l. Airport, Pittsburgh, PA. Flight 427 was operating under the provisions of 14 code of federal regulations (CFR) part 121 as a scheduled domestic passenger flight from Chicago-O'Hare Int'l. Airport, Chicago, Il, to Pittsburgh. The flight departed about 1810, with 2 pilots, 3 flight attendants, and 127 passengers on board. The airplane entered an uncontrolled descent and impacted terrain near Aliquippa, PA. All 132 people on board were killed, and the airplane was destroyed by impact forces and fire. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require Boeing to update its Boeing 737 simulator package to reflect flight test data on crossover airspeed and then require all operators of the Boeing 737 to incorporate these changes in their simulators used for Boeing 737 pilot training. (Supersedes Safety Recommendation A-96-107, A-96-109, A-96-112, and A-96-113)
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: ALIQUIPPA, PA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA94MA076
Accident Reports: Uncontrolled Descent and Collision With Terrain, USAir Flight 427, Boeing 737-300, N513AU
Report #: AAR-99-01
Accident Date: 9/8/1994
Issue Date: 4/16/1999
Date Closed: 1/3/2002
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Simulator,Training and Education

Safety Recommendation History
From: NTSB
To: FAA
Date: 1/3/2002
Response: Although the Board is concerned that the FAA did not confirm, as requested, that it had verified that the simulators provide realistic responses when demonstrating crossover at all altitudes when the rudder limiter has failed, the Board believes that the actions taken by the FAA meet the basic intent of the recommendation. Consequently, Safety Recommendation A-99-26 is classified "Closed--Acceptable Action."

From: FAA
To: NTSB
Date: 10/1/2001
Response: Letter Mail Controlled 10/05/2001 12:57:13 PM MC# 2010796: As stated in the FAA's letter dated February 27, 2001, all Boeing 737 series flight simulators have been updated to reflect aerodynamic revisions related to roll and yaw characteristics of the Boeing 737-100, -200, -300, -400, and -500 series airplanes more accurately. The National Simulator Program has evaluated each 737 simulator and found that they accurately reflect these models and the changes in 737 rudder operations as directed in Airworthiness Directive (AD) 97-14-03. The AD requires installation of a newly designed rudder-limiting device that reduces rudder authority during specific flight conditions and installation of a newly designed yaw damper system. On June 14, 2001, the Board stated that while it believes the FAA's action meets the intent of the safety recommendation, it would like assurance that the simulator will provide crossover speed training at all altitudes with the rudder limiter failed. The FAA has updated the simulators with the model and flight test data that has been made available by Boeing to the operators. There are no outstanding concerns regarding related issues as the simulators have been checked out thoroughly against all available data within the realm of reasonable simulation. Failure of the rudder limiter and hardover rudder malfunctions may be inserted by various methods, and it is normal practice to leave the exact methods to each operator's discretion in its training program. Under the current regulations, the FAA has no reason to believe that the aerodynamic model implemented in the simulators and the responses associated with the related malfunctions as described do not behave as expected based on the data available. I consider the FAA's action to be completed on this safety recommendation.

From: NTSB
To: FAA
Date: 6/14/2001
Response: The FAA's action appears to meet the intent of this recommendation. However, the Safety Board would like to be sure that the new simulator package includes the ability to insert a failure of the rudder limiter and that the aerodynamic model covers rudder motion to blow down. That is, the Safety Board would like assurances that the simulator will provide crossover speed training at all altitudes with the rudder limiter failed. Pending further correspondence, Safety Recommendation A-99-26 remains classified "Open--Acceptable Response."

From: FAA
To: NTSB
Date: 2/27/2001
Response: Letter Mail Controlled 03/05/2001 3:54:31 PM MC# 2010187 All Boeing 737 series flight simulators have been updated to reflect aerodynamic revisions related to roll and yaw characteristics of the Boeing 737-100, -200, -300, -400, and -500 series airplanes more accurately. The National Simulator Program has evaluated each 737 simulator and found that they accurately reflect these models and the changes in 737 rudder operations as directed in Airworthiness Directive (AD) 97-14-03. The AD required installation of a newly designed rudder-limiting device that reduces rudder authority during specific flight conditions and installation of a newly designed yaw damper system.

From: NTSB
To: FAA
Date: 4/12/2000
Response: The FAA stated that on April 30, 1999, Boeing, based on new flight test results, updated the 737-300 aerodynamic model, which more accurately represents roll and yaw characteristics of 737-300s. As a result of the new Boeing flight test data, the FAA sent a letter to all U.S. operators of 737-300 simulators on May 28, 1999, requiring that the 737-300 aerodynamic revisions be incorporated in the 737-300 flight simulators by October 1, 1999. In addition, similar handling characteristics exhibited by other 737 models will result in the development of revisions to other 737 simulator models. The FAA will issue letters to applicable 737 operators requiring that these revisions be incorporated into applicable flight simulators when Boeing completes the revisions to other 737 models. The Safety Board is interested to know whether flight tests will be conducted of other 737 series airplanes to obtain the necessary crossover speed data. Additionally, the Safety Board requests that the FAA provide a schedule as to when the updated simulation models for the other 737 series will be available to the operators. Pending the revisions to all 737 series flight simulators, Safety Recommendation A-99-26 is classified "Open-- Acceptable Response."

From: FAA
To: NTSB
Date: 6/25/1999
Response: Letter Mail Controlled 6/30/99 3:02:35 PM MC# 990699: On April 30, 1999, the Boeing Aircraft Company, based upon new flight test results, updated the Boeing 737-300 aerodynamic model, which more accurately represents roll and yaw characteristics of the Boeing 737-300 aircraft. In addition, similar handling characteristics exhibited by other Boeing 737 models will result in the development of revisions to other Boeing 737 simulator models. As a result of new Boeing flight test data, the FAA sent a letter to all U.S. operators of Boeing 737-300 simulators on May 28, 1999, requiring that the Boeing 737-300 aerodynamic revisions be incorporated in the Boeing 737-300 flight simulators by October 1, 1999. I have enclosed copies of the letters for the Board's information. The FAA will also issue similar letters to applicable operators when Boeing completes the revisions to other Boeing 737 models. I consider the FAA's action to be completed on this safety recommendation.