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Safety Recommendation Details

Safety Recommendation A-96-131
Details
Synopsis: ON 11/12/95, AT 0056 EASTERN TIME (EST), AMERICAN AIRLINES (AAL) FLIGHT 1572, A MCDONNELL DOUGLAS MD-80, REGISTERED IN THE UNITED STATES AS N566AA, STRUCK TREES ON A RIDGE LINE NORTHEAST OF THE AIRPORT, IN EAST GRANBY, CONNECTICUT, WHICH IS ABOUT 2.54 MILES FROM THE END OF RUNWAY 15, AT BRADLEY INTERNATIONAL AIRPORT (BDL) WINDSOR LOCKS, CONNECTICUT. THE TREE STRIKE OCCURRED DURING AN INSTRUMENT APPROACH TO RUNWAY 15 IN DARKNESS & IN VARIABLE WIND CONDITIONS. BOTH ENGINES SUBSEQUENTLY LOST POWER FOLLOWING INGESTION OF TREE LIMBS, BUT THE FLIGHTCREW WAS ABLE TO CONTINUE THE FLIGHT TO THE AIRPORT. THE AIRPLANE WAS SUBSTANTIALLY DAMAGED DURING THE EMERGENCY LANDING. ONE OF THE 72 PASSENGERS RECEIVED A MINOR INJURY DURING THE EMERGENCY EVACUATION, & NONE OF THE FIVE CREWMEMBERS WAS INJURED IN THE ACCIDENT. THE FLIGHT, WHICH WAS OPERATING UNDER 14 CODE OF FEDERAL REGULATIONS PART 121, ORIGINATED AT O"HARE INTERNATIONAL AIRPORT, CHICAGO, ILLINOIS, ABOUT 2 HOURS BEFORE THE ACCIDENT.
Recommendation: THE NTSB RECOMMENDS THAT THE FAA: INCLUDE A MORE COMPREHENSIVE SET OF GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS IN THE TERMINAL INSTRUMENT PROCEDURES (TERPS) (FAA ORDER 8260.3B) HANDBOOK, CLARIFYING THE DEFINITION OF PRECIPITOUS TERRAIN, & ESTABLISHING DEFINED CRITERIA FOR ADDRESSING THE POTENTIAL EFFECTS OF OF SUCH TERRAIN.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: EAST GRANBY, CT, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA96MA008
Accident Reports: Collision with Trees on Final Approach American Airlines Flight 1572, McDonnell Douglas MD-83, N566AA
Report #: AAR-96-05
Accident Date: 11/12/1995
Issue Date: 12/3/1996
Date Closed: 9/4/2008
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s):

Safety Recommendation History
From: NTSB
To: FAA
Date: 9/4/2008
Response: On November 20, 2006, the FAA informed the Safety Board that it was implementing software for identifying precipitous terrain and developing appropriate instrument procedures. In its May 15, 2008, letter, the FAA stated that over 1,600 new and revised instrument approach procedures had been evaluated for the effects of precipitous terrain and that this number increases with every instrument procedure publication cycle date. In previous meetings and letters, the FAA has stated that changes to the TERPS Handbook would be done through a notice of proposed rulemaking (NPRM). However, in its May 15, 2008, letter, the FAA indicated that effective December 7, 2007, without an NPRM, Change 20 to Order 8260.3B incorporated guidance/criteria for instrument approach procedures in precipitous terrain. With the issuance of Change 20 to FAA Order 8260.3B, the FAA has completed the action recommended. Consequently, Safety Recommendation A-96-131 is classified Closed Acceptable Action.

From: FAA
To: NTSB
Date: 5/15/2008
Response: Letter Mail Controlled 5/28/2008 11:24:36 AM MC# 2080271: Robert A. Sturgell, Acting Administrator, FAA, 5/15/08 The Federal Aviation Administration implemented precipitous terrain identification software evaluating instrument procedures within the last 2 years. A check with the National Flight Procedures Office indicates over 1,600 new and revised instrument approach procedures have been evaluated for the effects of precipitous terrain to date. This number increases with every instrument procedure publication cycle date. At a previous meeting, the FAA indicated that the Change 20 to the TERPS handbook would be done through a notice of proposed rulemaking (NPRM). Since then, without an NPRM, we have incorporated interim guidance/criteria for precipitous terrain into FAA Order 8260.3B, Change 20, and it’s titled “United States Standard for Terminal Instrument Procedures,” which was effective December 7, 2007 (copy enclosed). We have acted upon this safety recommendation and we are conducting precipitous terrain evaluations on every new instrument approach procedure, and during the biennial review process for existing procedures.

From: NTSB
To: FAA
Date: 4/19/2007
Response: In a letter dated September 14, 2000, the FAA reported that the National Center for Atmospheric Research (NCAR) had completed a software package to examine any segment of an approach for precipitous terrain and to specify a minimum adjustment to obstacle clearance. The FAA anticipated that new precipitous terrain criteria and associated software would be completed by April 2001, and that the FAA would revise the TERPS handbook to require use of the software. On November 20, 2000, the Safety Board classified this recommendation Open Acceptable Response. On December 12, 2003, staff from the Safety Board and the FAA met to discuss a number of open recommendations, including Safety Recommendation A-96-131. At that time, the FAA indicated that Change 20 to the TERPS handbook would include the actions recommended, and that a notice of proposed rulemaking (NPRM) for Change 20 was scheduled to be issued in January 2004, with final implementation to follow a few months later. After the meeting, the FAA staff updated this information to indicate that the NPRM would be issued by May 2004. In a recent letter, the FAA reports that it has completed the tasks to define precipitous terrain, and develop consistent criteria for adjustments in areas of precipitous terrain. The FAA further reports that, in cooperation with NCAR, it has developed algorithms for the declaration of precipitous terrain and its adjustment, and that software has been developed and implemented to identify precipitous terrain and to provide the precipitous terrain adjustment value. The FAA also states that a requirement to use the precipitous terrain identification software will be included in FAA Order 8260.3B, Change 20. In the November 20, 2006, letter, the FAA anticipated that the NPRM would be published by the end of 2006. Safety Board staff has since learned that the FAA now believes that the NPRM will be published by May 2007. In the interim, the FAA has issued a memorandum directing implementation of the precipitous terrain identification program as soon as possible; the software was officially implemented on September 6, 2005. Although the FAA is taking the actions recommended, the Safety Board is disappointed that the recommendation will be more than 10 years old by the time this effort is completed. The Board recognizes the efforts the FAA has made to implement interim improvements until the NPRM is published. The FAA’s activities to develop the improved precipitous terrain algorithm and software, and to implement these improvements until the NPRM is issued are responsive to this recommendation. Pending issuance by May 2007 of the NPRM adding Change 20 to Order 8260.3B, including a requirement to use the precipitous terrain identification software, Safety Recommendation A-96-131 remains classified Open Acceptable Response.

From: FAA
To: NTSB
Date: 11/20/2006
Response: Letter Mail Controlled 12/4/2006 10:14:08 AM MC# 2060578:The Federal Aviation Administration has completed the tasks to define precipitous terrain, and development of consistent criteria for adjustments in areas of precipitous terrain. The FAA, in cooperation with the National Center for Atmospheric Research, developed a set of algorithms that can be weighted and combined to give the declaration of precipitous terrain and its adjustment. Also, a software program was written, validated, and implemented that identifies precipitous terrain and provides the precipitous terrain adjustment value. The precipitous terrain software program is based upon the combined effect of five parameters computed from digital terrain elevation data, which has a data density of a 3 arc second separation or less (100 meters or less) between adjoining data points. The five parameters are determined over an entire flight segment plus a 2 nautical mile buffer beyond the segment's lateral boundaries. There are five weighted parameters that are used to determine whether the underlying terrain is high enough, steep enough, and/or rough enough to be considered precipitous. The five parameters are: The average elevation; The slope of the plane of best fit; The standard deviation from the plane of best fit; The maximum elevation differential over the entire area; and The maximum elevation differential among all 1 nautical mile diameter circles centered upon each data point within the entire area. Based upon the five weighted parameters as a model analysis, terrain underlying a flight segment is deemed precipitous if the software program identifies it as such. The requirement to use the computer driven precipitous terrain identification software program will be included in FAA Order 8260.3B, Change 20 of “United States Standard for Terminal Instrument Procedures” (TERPS). It is anticipated that Change 20 of the TERPS will be published by the end of 2006. In the interim, the FAA issued a memorandum to the National Flight Procedures Office (NFPO) directing implementation of the precipitous terrain identification program as soon as it could be integrated into the FAA’s procedures automation program. The NFPO officially implemented the program for approach procedure development effective September 6, 2005. The precipitous terrain program has been implemented for all new procedure development and will also be run for existing procedures as they come under biennial review, A detailed explanation of the weighted parameters and algorithms is enclosed for the Board’s information. The FAA will provide the Board with a copy of the TERPS change 20 as soon as it is issued.

From: NTSB
To: FAA
Date: 11/20/2000
Response: ALTHOUGH THE FAA'S ACTIONS ARE RESPONSIVE TO THE RECOMMENDATION, THE SAFETY BOARD WOULD APPRECIATE RECEIVING MORE INFORMATION ABOUT THE NCAR SOFTWARE AND THE FAA'S PLANS FOR USING THE RESULTS; THE WEIGHTED PARAMETERS TO BE USED TO DETERMINE WHETHER THE UNDERLYING TERRAIN IS HIGH ENOUGH, STEEP ENOUGH, AND/OR ROUGH ENOUGH TO BE CONSIDERED PRECIPITOUS; AND THE GUIDELINES TO BE USED FOR DETERMINING THE "MINIMUM ADJUSTMENTS" FOR TERRAIN. PENDING OUR RECEIPT OF FURTHER INFORMATION ABOUT THE FAA'S PROGRAM, A-96-131 REMAINS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 9/14/2000
Response: Letter Mail Controlled 09/20/2000 2:57:52 PM MC# 2001373 THE FAA IS CONTINUING ITS EFFORT TO REVISE THE GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS CURRENTLY CONTAINED IN THE TERMINAL INSTRUMENT PROCEDURES (TERPS) HANDBOOK. ON 4/30/00, THE NATIONAL CENTER FOR ATMOSPHERIC RESEARCH COMPLETED THE SOFTWARE PACKAGE TO EXAMINE ANY SEGMENT OF AN APPROACH FOR PRECIPITOUS TERRAIN. THE SOFTWARE WILL EXAMINE DIGITAL TERRAIN ELEVATION DATA FROM THE DEPT. OF DEFENSE MAPPING AGENCY'S TERRAIN ELEVATION DATA BASE. THIS SOFTWARE WILL USE WEIGHTED PARAMETERS TO DETERMINE IF THE TERRAIN UNDERLYING THE PRIMARY, SECONDARY, AND BUFFER AREA APPROACH SEGMENTS ARE HIGH ENOUGH, STEEP ENOUGH, AND/OR ROUGH ENOUGH TO BE CONSIDERED PRECIPITOUS. THE OUTPUT OF THIS SOFTWARE WILL SPECIFY THE MINIMUM ADJUSTMENT TO REQUIRED OBSTACLE CLEARANCE FOR PRECIPITOUS TERRAIN IN EACH SEGMENT. THE SOFTWARE IS BEING FIELD TESTED AND ADJUSTED AS NECESSARY. IT IS ANTICIPATED THAT IMPLEMENTATION OF THE NEW PRECIPITOUS TERRAIN CRITERIA AND ASSOCIATED SOFTWARE FOR PRECIPITOUS TERRAIN WILL BE COMPLETED BY APRIL 2001. ONCE THIS EFFORT IS COMPLETED, THE FAA WILL REVISE THE TERPS HANDBOOK TO REQUIRE THE USE OF THIS SOFTWARE TO IDENTIFY PRECIPITOUS TERRAIN AND TO DETERMINE THE MINIMUM REQUIRED ADJUSTMENT FOR SUCH TERRAIN. I WILL KEEP THE BOARD INFORMED OF THE FAA'S PROGRESS ON THIS RECOMMENDATION.

From: NTSB
To: FAA
Date: 8/20/1999
Response: A-96-131 ASKED THE FAA TO INCLUDE A MORE COMPREHENSIVE SET OF GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS IN THE TERMINAL INSTRUMENT PROCEDURES (TERPS) (FAA ORDER 8260.3B) HANDBOOK, CLARIFYING THE DEFINITION OF PRECIPITOUS TERRAIN, AND ESTABLISHING DEFINED CRITERIA FOR ADDRESSING THE POTENTIAL EFFECTS OF SUCH TERRAIN. PENDING FINAL MODIFICATION OF THE TERPS HANDBOOK, A-96-131 IS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 6/17/1999
Response: Letter Mail Controlled 6/18/99 3:33:09 PM MC# 990664 THE FAA IS CONTINUING ITS EFFORTS TO REVISE THE GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS CURRENTLY CONTAINED IN THE TERMINAL INSTRUMENT PROCEDURES (TERPS) HANDBOOK. THE NATIONAL CENTER FOR ATMOSPHERIC RESEARCH HAS DEVELOPED A PROTOTYPE SOFTWARE PACKAGE TO EXAMINE ANY SEGMENT OF AN APPROACH FOR PRECIPITOUS TERRAIN AND TO DETERMINE ADJUSTMENTS FOR PRECIPITOUS TERRAIN. THE SOFTWARE, WHICH IS UNDERGOING CONTINUED ANALYSIS WITHIN FAA, IS DESIGNED TO EXAMINE DIGITAL TERRAIN ELEVATION DATA FROM THE DEPT. OF DEFENSE MAPPING AGENCY'S TERRAIN ELEVATION DATA BASE. THIS SOFTWARE WILL USE WEIGHTED PARAMETERS TO DETERMINE IF THE TERRAIN UNDERLYING THE PRIMARY, SECONDARY, AND BUFFER AREA APPROACH SEGMENTS ARE HIGH ENOUGH, STEEP ENOUGH, AND/OR ROUGH ENOUGH TO BE CONSIDERED PRECIPITOUS. THE OUTPUT OF THIS SOFTWARE WILL SPECIFY THE MINIMUM ADJUSTMENT TO REQUIRED OBSTACLE CLEARANCE FOR PRECIPITOUS TERRAIN IN EACH SEGMENT. THE TERPS HANDBOOK WILL BE REVISED TO REQUIRE THE USE OF THIS SOFTWARE TO IDENTIFY PRECIPITOUS TERRAIN AND TO DETERMINE THE MINIMUM REQUIRED ADJUSTMENT FOR SUCH TERRAIN. I WILL KEEP THE BOARD INFORMED OF THE FAA'S PROGRESS ON THIS RECOMMENDATION.

From: NTSB
To: FAA
Date: 4/15/1998
Response: A-96-131 ASKED THE FAA TO INCLUDE A MORE COMPREHENSIVE SET OF GUIDELINES CONCERNING PRECIPITIOUS TERRAIN ADJUSTMENTS IN THE TERPS (FAA ORDER 8260.3D) HANDBOOK, CLARIFYING THE DEFINITION OF PRECITPITOUS TERRAIN, & ESTABLISHING DEFINED CRITERIA FOR ADDRESSING THE POTENTIAL EFFECTS OF SUCH TERRAIN. PENDING FURTHER RESPONSE FROM THE FAA, A-96-131 REMAINS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 1/28/1998
Response: THE FAA AGREES WITH THE INTENT OF THIS RECOMMENDATION & IS DEVELOPING A PLAN IN CONJUNCTION WITH THE GOVERNMENT INDUSTRY CHARTING FORUM TO REVISE THE GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS CURRENTLY CONTAINED IN THE TERMINAL INSTRUMENT PROCEDURES HANDBOOK. THE FAA HAS RECEIVED APPROPRIATE FUNDING FOR THIS EFFORT, & A CONTRACT HAS BEEN NEGOTIATED WITH THE NATIONAL CENTER FOR ATMOSPHERIC RESEARCH TO DEVELOP A PLAN OF ACTION TO ADDRESS THIS RECOMMENDATION. THE CONTRACT CALLS FOR THE FINDINGS TO BE PROVIDED TO THE FAA BY THE END OF FISCAL YEAR 1998.

From: NTSB
To: FAA
Date: 6/26/1997
Response: A-96-131 ASKED THE FAA TO INCLUDE A MORE COMPREHENSIVE SET OF GUIDELINES CONCERNING PRECIPITOUS TERRAIN ADJUSTMENTS IN THE TERPS (FAA ORDER 8260.3B) HANDBOOK, CLARIFYING THE DEFINITION OF PRECIPITOUS TERRAIN, & ESTABLISHING DEFINED CRITERIA FOR ADDRESSING THE POTENTIAL EFFECTS OF SUCH TERRAIN. PENDING RECEIPT OF THE REVISED GUIDELINES, A-96-131 IS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 2/24/1997
Response: THE FAA AGREES WITH THE INTENT OF THE RECOMMENDATION & IS DEVELOPING A PLAN TO REVISE THE PRECIPITOUS TERRAIN GUIDELINES IN THE TERPS HANDBOOK.