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General Aviation Safety
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.
TO THE FEDERAL AVIATION ADMINISTRATION: Establish a joint Government-industry working group to address, understand, and develop effective operational strategies and guidance to reduce thunderstorm penetrations, and verify that these strategies and guidance materials are incorporated into air carrier flight manuals and training programs as the strategies become available. The working group should focus its efforts on all facets of the airspace system, including ground- and cockpit-based solutions. The near-term goal of the working group should be to establish clear and objective criteria to facilitate recognition of cues associated with severe convective activity and guidance to improve flight crew decision-making.
Original recommendation transmittal letter:
Closed - Unacceptable Action
LITTLE ROCK, AR, United States
Runway Overrun During Landing, American Airlines Flight 1420, McDonnell Douglas MD-82
Addressee(s) and Addressee Status:
FAA (Closed - Unacceptable Action)
Decision Making, Flightcrew, Thunderstorms/Rain/Snow, Training and Education, Weather
Safety Recommendation History
The FAA replied that it believes that the January 19, 2006, issuance of Advisory Circular (AC) 120-88A, Preventing Injuries Caused by Turbulence, meets the intent of this recommendation. The AC was the product of a Government-industry working group, the Commercial Aviation Safety Team. The FAA stated that the AC contains effective operational strategies and guidance for avoiding turbulence from all sources, including thunderstorms. The FAA emphasized that Appendix 2 of the AC is based on guidance used by the US Air Force regarding avoidance of thunderstorm penetrations and that this guidance includes clear and objective criteria. Although the FAA had not written to the Safety Board about this recommendation since February 19, 2002, it was discussed in detail at meetings between FAA and Board staff on December 12, 2003, and August 30, 2004. In advance of the August 30, 2004, meeting, the FAA provided a draft copy of AC 120-88A. What is now Appendix 2 of AC 120-88A was included in this draft, and FAA staff indicated at the meeting their belief that this appendix was fully responsive to the recommendation. Board staff disagreed and replied that the recommendation sought (1) to determine the reasons why pilots penetrate convective activity and (2) to develop operational strategies and guidance to reduce thunderstorm penetrations. Board staff believed that the draft AC did not address thunderstorm penetrations on final approach. Board staff were also concerned that this guidance had been included in an appendix of an AC about avoiding turbulence injuries, whereas the issue addressed by the recommendation was windshear and other hazards associated with continued flight in convective activity. In the letter that transmitted this recommendation to the FAA, the Safety Board stated that most airlines and flight training programs instruct pilots to avoid thunderstorms during routine operations. However, data gathered from accident and incident investigations demonstrate that pilots frequently penetrate thunderstorms—in some cases with catastrophic results. A June 1999 report sponsored by the National Aeronautics and Space Administration (NASA) and based on research conducted by Massachusetts Institute of Technology’s Lincoln Laboratory used weather radar and air traffic radar data to document 60 hours of observations of flight crew behavior in the Dallas/Fort Worth, Texas, terminal area during convective activity. This research documented that pilots routinely penetrated thunderstorms with precipitation intensity levels of 3 (strong), 4 (very strong), and 5 (extreme) rather than deviate around them, especially when approaching an airport to land. Of the 1,952 encounters with thunderstorm cells recorded in these data, pilots penetrated the thunderstorms 1,310 times (67 percent). A followup study conducted at Memphis Airport found similar results. The letter transmitting this recommendation further stated that some air carriers provide their flight crews with only general, advisory information regarding severe weather avoidance, leaving individual flight crews responsible for making decisions about whether to continue an approach near convective activity. Such decisions are typically based on the pilots’ subjective assessment of the severity of the situation and on their experience. However, other carriers provide their pilots with specific operational guidance, including decision aids and flow charts in quick reference checklists and detailed lists of specific cues and operational criteria from which flight crews can easily assess weather conditions and objectively determine whether they can safely continue or need to take a different course of action. The intent of Safety Recommendation A-01-55 was the issuance of guidance/decision aids to improve the safety of operations in terminal areas when thunderstorms are present. Although the Safety Board believes that AC 120-88A is beneficial, it is of limited relevance to Safety Recommendation A-01-55. Unlike the FAA, the Board does not believe that the guidance provided in Appendix 2 of the AC is an improvement over FAA guidance about thunderstorm avoidance that was available when the Little Rock accident occurred. Despite detailed discussions with Board staff 4 years ago about why this guidance is not responsive to the recommendation, the FAA’s position has not changed. Consequently, Safety Recommendation A-01-55 is classified Closed Unacceptable Action.
Letter Mail Controlled 6/17/2008 10:38:05 AM MC# 2080332: Robert A. Sturgell, Acting Administrator, FAA, 6/11/08 The Federal Aviation Administration published Advisory Circular (AC) 120-88A, Preventing Injuries Caused by Turbulence, January 19, 2006 (copy enclosed). This AC was the product of a government-industry working group, the Commercial Aviation Safety Team, and the FAA believes it addresses the Board’s concern. AC 120-88A contains effective operational strategies and guidance for avoiding turbulence from all sources, including thunderstorms, considering all facets of the airspace system, including ground and cockpit-based solutions. The AC also recommends that the practices become a part of the standard operating procedures and be reinforced in training. Appendix 2 is devoted specifically to avoidance of thunderstorm penetrations and includes clear and objective criteria. Safety Alert for Operators 05007, issued December 7, 2005, (copy enclosed) announced the availability of AC 120-88 and recommended that directors of safety, directors of operations, trainers, aircraft dispatchers, and crewmembers of transport category airplanes be familiar with the content of AC 120-88 and should apply that content as appropriate in their daily operations.
The Safety Board disagrees that current guidance is satisfactory. The letter that transmitted this recommendation to the FAA discusses a June 1999 study sponsored by the National Aeronautics and Space Administration and conducted by the Massachusetts Institute of Technology's Lincoln Laboratory. This study documented flight crew behavior during 60 hours of observations in the Dallas/Fort Worth terminal area during convective activity. This research documented that pilots routinely penetrated thunderstorms with precipitation intensity levels of 3 (strong), 4 (very strong), and 5 (extreme) rather than deviate around them, especially when approaching an airport to land. Of the 1,952 encounters with thunderstorm cells recorded in these data, pilots penetrated the thunderstorms 1,310 times (67 percent). Since the recommendation letter was issued, Safety Board staff has received an update on this research that found similarly high levels of thunderstorm penetrations at the Memphis terminal. The Board notes that these studies were conducted after the results of the FAA's 1987 and 1997 activities, indicating that the training aids have not been effective in reducing pilot penetration of thunderstorm activity when landing. Safety Recommendation A-01-55 asks for the working group to develop effective operational strategies; verify that these strategies and guidance have been incorporated into air carrier training and manuals; and, for the near-term, establish clear and objective criteria to facilitate recognition of cues associated with severe convective activity and guidance to improve flight crew decision-making near thunderstorms in the terminal area. The Safety Board cannot determine from the FAA's description of the CAST working group's charter whether the group has these goals. Pending clarification of the CAST working group goals and the FAA's reconsideration, Safety Recommendation A-01-55 is classified "Open--Unacceptable Response."
Letter Mail Controlled 02/21/2002 7:49:04 PM MC# 2020178 Joint government-industry working groups have been convened in the past and have produced useful strategies relating to the reduction of thunderstorm penetrations. Those strategies have been captured in the FAA's 1987 Windshear Training Aid and the 1997 joint FAA-industry Turbulence Training Aid. Both training aids establish clear and objective criteria to facilitate near-term recognition of cues associated with severe convective activity and guidance to improve flightcrew decision-making. Both training aids have been widely distributed and remain available to the public upon request to the National Technical Information Service. More recently, another working group has been convened under the Commercial Aviation Safety Team (CAST) to focus, once again, on turbulence and severe convective activity. The charter of the working group is to look at new strategies to include ground- and cockpit-based solutions. The FAA is carefully watching the progress of the working group for outputs to supplement existing material in the training programs and manuals used by flightcrews. I believe that the FAA has addressed this safety issue completely, and I consider the FAA's action to be completed on this safety recommendation.
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