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From:
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NTSB
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To:
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FAA
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Date:
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6/27/2008
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Response:
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[The Safety Board addressed this recommendation in its June 27, 2008, letter to the FAA issuing recommendations as a result of the February 18, 2007, runway overrun of Delta Connection flight 6448] At the time of the accident, Shuttle America did not require landing distance assessments based on conditions at the time of arrival. Safety Alert for Operators (SAFO)5 06012, "Landing Performance Assessments at the Time of Arrival (Turbojets)," which the FAA issued about 6 months before the accident, had urgently recommended that operators of turbojet airplanes develop procedures for flight crews to assess landing performance based on the actual conditions at the time of arrival, which might differ from the presumed conditions at the time of dispatch, and that an additional safety margin of at least 15 percent be added to actual landing distances.
The aircraft performance study included a landing performance data calculation that most closely matched the landing distance assessment that the flight crewmembers might have accomplished if Shuttle America had incorporated procedures that were consistent with SAFO 06012. This calculation was based on the reported winds, a braking action report of fair, and the accident airplane’s flaps 5 configuration. The calculation assumed a touchdown point of 1,400 feet, the use of maximum reverse thrust until 60 knots, and full wheel braking and included an additional 15-percent stopping distance margin. The landing performance calculation showed that, on the basis of the conditions that had been reported to the flight crew at the time, the airplane could have landed with a factored touchdown point of 1,610 feet and come to a safe stop on the runway with a ground roll distance of 3,262 feet, for a total distance of 4,872 feet. However, the airplane’s actual touchdown point and the flight crew’s use of reverse thrust and braking were not in accordance with the assumptions used in the landing performance calculation.
Before the issuance of SAFO 06012, the FAA had planned to issue Operations Specification (OpSpec) N 8400.C082 to all 14 CFR Part 91 subpart K, 121, 125, and 135 turbojet operators in response to Safety Recommendation A-06-16 (urgent), the intent of which was to ensure adequate safety margins for landings on contaminated runways.6 The FAA had intended for operators to comply with the OpSpec by October 2006 but instead encountered industry opposition to the OpSpec. Consequently, in August 2006, the FAA decided not to issue the mandatory OpSpec but rather to pursue formal rulemaking and issue the voluntary SAFO in the interim.
In its final report on the Southwest Airlines flight 1248 accident,7 the Safety Board concluded, "although landing distance assessments incorporating a landing distance safety margin are not required by regulation, they are critical to safe operation of transport-category airplanes on contaminated runways." As a result, on October 4 and 16, 2007, the Board issued Safety Recommendations A-07-57 (urgent) and -61, respectively, to further address the need for landing distance assessments.
Safety Recommendation A-07-57 asked the FAA to immediately require all Part 121, 135, and 91 subpart K operators to conduct arrival landing distance assessments before every landing that are based on existing performance data and actual conditions and incorporate a minimum safety margin of 15 percent. This recommendation, which superseded Safety Recommendation A-06-16, was classified "Open--Unacceptable Response" on October 4, 2007, because it maintained the previous classification of Safety Recommendation A-06-16 and the FAA had not yet required landing distance assessments that incorporated a minimum safety margin of 15 percent.
Safety Recommendation A-07-61 asked the FAA to require all Part 121, 135, and 91 subpart K operators to accomplish arrival landing distance assessments before every landing that are based on a standardized methodology involving approved performance data, actual arrival conditions, and a means of correlating the airplane’s braking ability with runway surface conditions using the most conservative interpretation available and that include a minimum safety margin of 15 percent. The Safety Board recognized that the standardized methodology recommended in Safety Recommendation A-07-61 would take time to develop and, thus, issued Safety Recommendation A-07-57 to ensure that landing distance assessments with at least a 15-percent safety margin were being performed in the interim.
In its December 17, 2007, response to Safety Recommendation A-07-57, the FAA reported that, on the basis of its survey of Part 121 operators, 92 percent of U.S. air carrier passengers were being transported by carriers that had adopted SAFO 06012 in full or in part. However, the FAA did not indicate the percentage of Part 121 carriers that had fully adopted the SAFO or those parts of the SAFO that had not been adopted by other Part 121 carriers. The Safety Board is especially concerned that among those parts of the SAFO that have not yet been adopted is the minimum 15-percent landing distance safety margin. Also, the FAA did not provide any information regarding whether SAFO 06012 had been adopted in full or in part by Part 135 and Part 91 subpart K operators. In addition, the FAA did not describe the actions that it would take to encourage those operators that have not complied with the SAFO (such as Shuttle America) to do so. Because all Part 121, 135, and 91 subpart K operators have not fully complied with SAFO 06012 and rulemaking that requires arrival landing distance assessments with a 15-percent minimum safety margin has not been implemented, Safety Recommendation A-07-57 remains classified "Open--Unacceptable Response."
In its January 8, 2008, response to Safety Recommendation A-07-61, the FAA stated that, in December 2007, it had announced the formation of an aviation rulemaking committee to review regulations affecting certification and operation of airplanes and airports for takeoff and landing operations on contaminated runways. The Safety Board recognizes that aviation rulemaking committees are part of the rulemaking process, but these committees have historically taken a long time to complete their work, and the FAA has not always acted in a timely manner after it receives recommendations from the committees. Pending the prompt completion of the aviation rulemaking committee’s work and the FAA’s timely action in response to the committee’s recommendations, Safety Recommendation A-07-61 is classified "Open--Acceptable Response." The Board continues to urge the FAA to act expeditiously on Safety Recommendations A-07-57 and -61 because landing distance assessments are critical to safe landing operations on contaminated runways.
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