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Safety Recommendation Details

Safety Recommendation A-01-061
Synopsis: On June 1, 1999, at 2350:44 central daylight time, American Airlines flight 1420, a McDonnell Douglas DC-9-82 (MD-82), N215AA, crashed after it overran the end of runway 4R during landing at Little Rock National Airport in Little Rock, Arkansas. Flight 1420 departed from Dallas/Fort Worth International Airport, Texas, about 2240 with 2 flight crewmembers, 4 flight attendants, and 139 passengers aboard and touched down in Little Rock at 2350:20. After departing the end of the runway, the airplane struck several tubes extending outward from the left edge of the instrument landing system localizer array, located 411 feet beyond the end of the runway; passed through a chain link security fence and over a rock embankment to a flood plain, located approximately 15 feet below the runway elevation; and collided with the structure supporting the runway 22L approach lighting system. The captain and 10 passengers were killed; the first officer, the flight attendants, and 105 passengers received serious or minor injuries; and 24 passengers were not injured. The airplane was destroyed by impact forces and a postcrash fire. Flight 1420 was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 121 on an instrument flight rules (IFR) flight plan.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Provide additional information on the Low Level Windshear Alert System (LLWAS) in the Aeronautical Information Manual, including that an LLWAS alert is a valid indicator of windshear or a microburst.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: LITTLE ROCK, AR, United States
Is Reiterated: No
Is Hazmat: No
Accident #: DCA99MA060
Accident Reports: Runway Overrun During Landing, American Airlines Flight 1420, McDonnell Douglas MD-82
Report #: AAR-01-02
Accident Date: 6/1/1999
Issue Date: 12/10/2001
Date Closed: 8/10/2004
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Low Level Windshear, Weather, Wind

Safety Recommendation History
From: NTSB
Date: 8/10/2004
Response: On February 19, 2004, the FAA issued a new edition of the AIM that provides information to pilots on LLWAS and alert data for controllers. A corresponding change, effective February 19, 2004, was also included in the Aeronautical Information Publication. These revisions are fully responsive to Safety Recommendation A-01-61, which is now classified "Closed--Acceptable Action."

From: FAA
Date: 5/14/2004
Response: Letter Mail Controlled 5/24/2004 12:02:04 PM MC# 2040239 Additional information has been included in the February 19, 2004, edition of the Aeronautical Information Manual (AIM) to provide information to pilots on Low Level Wind Shear Alert System (LLWAS) and alert data for controllers. LLWAS provides windshear information but not microburst alerts. LLWAS "Network Expansion," which is integrated with Terminal Doppler Weather Radar (TDWR), and LLWAS "Relocation/Sustainment" provide the capability of displaying microburst alerts, windshear alerts, and wind information oriented to the threshold or departure end of a runway. TDWR and Weather Systems Processors (WSP) are designed to detect windshear and microburst activity. The Integrated Terminal Weather System (ITWS) also provides detection and alerting for possible tornado activity, microbursts, and windshear. The associated ribbon display allows the controller to read the displayed alert without any need for interpretation. I have enclosed a copy of the pertinent revisions to the AIM for the Board's information. The following is a summary of the changes: · Paragraph 4-l-23, Weather System Processor (WSP), was added to provide a description of the WSP system and the weather products to which it provides warnings, including microburst and other hazardous windshear. · Paragraph 4-3-7, Low Level Wind Shear/Microburst Detection Systems, was modified to provide more complete information about the LLWAS in the National Airspace System. The information in this paragraph not only defines LLWAS configurations, but also provides information about ITWS, WSP, and TDWR. This paragraph also includes an overview of these systems, including their capabilities. · Paragraph 7-l-26, Microbursts, was added to explain the effects of microbursts and the systems that detect this hazardous weather event. A corresponding change was included in the Aeronautical Information Publication (AIP), which was effective February 19, 2004. I have also enclosed a copy of the changes to the AIP for the Board's information. I believe that the FAA has satisfactorily responded to this safety recommendation, and I look forward to your response.

From: NTSB
Date: 10/17/2002
Response: The FAA reports that it is modernizing detection systems for windshear/microbursts and that, although LLWAS is incorporated in the reporting, other systems are, as well. The FAA will revise the AIM to provide pilots with a better understanding of the overall concept. Pending these revisions being made to the AIM, Safety Recommendation A-01-61 is classified "Open--Acceptable Response."

From: FAA
Date: 2/19/2002
Response: Letter Mail Controlled 02/21/2002 7:49:04 PM MC# 2020178 Prior to issuance of this safety recommendation, the FAA proposed changes to the section pertaining to windshear/microburst systems in the Aeronautical Information Manual (AIM). The FAA is modernizing detection systems for windshear/microbursts and although LLWAS is incorporated in the reporting, there are other systems as well. The AIM will be revised to provide pilots with a better understanding of the overall concept.