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Safety Recommendation Details

Safety Recommendation A-10-065
Details
Synopsis: On January 15, 2009, about 1527 eastern standard time,1 US Airways flight 1549, an Airbus Industrie A320-214, N106US, experienced an almost total loss of thrust in both engines after encountering a flock of birds and was subsequently ditched on the Hudson River about 8.5 miles from LaGuardia Airport (LGA), New York City, New York. The flight was en route to Charlotte Douglas International Airport (CLT), Charlotte, North Carolina, and had departed LGA about 2 minutes before the in-flight event occurred. The 150 passengers, including a lap-held child, and 5 crewmembers evacuated the airplane via the forward and overwing exits. One flight attendant and four passengers received serious injuries, and the airplane was substantially damaged. The scheduled, domestic passenger flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 121 on an instrument flight rules flight plan. Visual meteorological conditions prevailed at the time of the accident.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: During the bird-ingestion rulemaking database (BRDB) working group‘s reevaluation of the current engine bird-ingestion certification regulations, specifically reevaluate the 14 Code of Federal Regulations (CFR) 33.76(d) large flocking bird certification test standards to determine whether they should 1) apply to engines with an inlet area of less than 3,875 square inches and 2) include a requirement for engine core ingestion. If the BRDB working group‘s reevaluation determines that such requirements are needed, incorporate them into 14 CFR 33.76(d) and require that newly certificated engines be designed and tested to these requirements.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Weehawken, NJ, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA09MA026
Accident Reports: Loss of Thrust in Both Engines, US Airways Flight 1549 Airbus Industrie A320-214, N106US
Report #: AAR-10-03
Accident Date: 1/15/2009
Issue Date: 5/21/2010
Date Closed: 3/1/2016
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Engine,Rulemaking,Wildlife

Safety Recommendation History
From: NTSB
To: FAA
Date: 8/24/2018
Response: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM) titled, “Medium Flocking Bird [MFB] Test at Climb Condition,” which was published at 83 Federal Register 31479 on July 6, 2018. The NTSB investigated the January 15, 2009, accident involving US Airways flight 1549, an Airbus A320-214, which experienced an almost total loss of thrust in both engines after encountering a flock of birds and was subsequently ditched on the Hudson River about 8.5 miles from LaGuardia Airport (LGA), New York City, New York. The flight had departed LGA about 2 minutes before the bird encounter occurred; the airplane was at an altitude of 2,818 ft above ground level and a distance of about 4.5 miles north-northwest of the departure end of runway 4 at LGA. The NTSB determined that the probable cause of this accident was the ingestion of large birds into each engine, which resulted in an almost total loss of thrust in both engines and the subsequent ditching on the Hudson River.2 As a result of its investigation, the NTSB issued numerous safety recommendations, including the following two recommendations to the FAA: Modify the 14 Code of Federal Regulations 33.76(c) small and medium flocking bird certification test standard to require that the test be conducted using the lowest expected fan speed, instead of 100-percent fan speed, for the minimum climb rate. (A-10-64) During the bird-ingestion rulemaking database (BRDB) working group’s reevaluation of the current engine bird-ingestion certification regulations, specifically reevaluate the 14 Code of Federal Regulations (CFR) 33.76(d) large flocking bird certification test standards to determine whether they should 1) apply to engines with an inlet area of less than 3,875 square inches and 2) include a requirement for engine core ingestion. If the BRDB working group’s reevaluation determines that such requirements are needed, incorporate them into 14 CFR 33.76(d) and require that newly certificated engines be designed and tested to these requirements. (A-10-65) In its NPRM, the FAA indicated that, as a result of the accident, it began studying how to improve engine durability with respect to engine core bird ingestion. The Aviation Rulemaking Advisory Committee (ARAC) working group produced a report titled, “Turbofan Bird Ingestion Regulation Engine Harmonization Working Group Report,” dated February 19, 2015, which concluded that modern fan blades (such as those on the accident airplane’s engines) have relatively wider fan blade chords than those in service when the current MFB ingestion test (in 14 CFR 33.76[c]) was developed and adopted. The ARAC working group report also pointed out that the current MFB ingestion test is conducted with the engine operating at 100% takeoff power or thrust; this setting is ideal for testing the fan blades but does not represent the lower fan speeds used during the climb and descent phases of aircraft flight. The FAA indicated that it agrees with the ARAC working group conclusion that, for modern engine designs, the existing 14 CFR 33.76(c) small and medium flocking bird test does not demonstrate engine core flow robustness against bird ingestion as intended. The FAA indicated that the ARAC working group report included recommendations consistent with this proposed rule and that the ARAC working group addressed both A-10-64 and -65. In response to A-10-64, the ARAC working group recommended the tests in this proposed rule. The FAA noted that the ARAC working group found that its recommendation would also address the intent of A-10-65 because the kinetic energy of the bird in the proposed rule is of the same magnitude as that required for the large flocking bird test. Safety Recommendation A-10-64 is currently classified “Open—Acceptable Alternate Response” pending the FAA’s proposed revisions to 14 CFR 33.76. The proposed rule, when implemented, would satisfy the intent of Safety Recommendation A-10-64. Safety Recommendation A-10-65 was classified “Closed—Acceptable Action” on March 1, 2016, in part because the ARAC found that the new climb condition MFB test will further assure the robustness of the engine core. The NTSB supports issuance of the proposed revisions and appreciates the opportunity to comment on this NPRM.

From: NTSB
To: FAA
Date: 3/1/2016
Response: You previously told us that a joint FAA and Aerospace Industry Association working group (1) completed its update of the BRDB, (2) reevaluated the large flocking bird certification requirements of section 33.76(d), and (3) found that engines with an inlet area of less than 3,875 square inches are currently operating near the safety objective of the current rule, and that it believed no further revisions are appropriate at this time. We told you that these actions satisfied part (1) of Safety Recommendation A-10-65, and that the ARAC would address part (2) by considering large flocking bird species and whether a new core ingestion requirement is necessary. We note that the ARAC found that (1) the existing medium flocking bird test is at least as stringent for this size engine as the large flocking bird test is for larger engines and (2) a new climb condition medium flocking bird test will further assure the robustness of the engine core. We also note that, based on these findings, the ARAC determined that a new engine core ingestion requirement is not needed. We believe that the ARAC’s consideration of whether a requirement for engine core ingestion is needed satisfies the final part of Safety Recommendation A-10-65, which is classified CLOSED—ACCEPTABLE ACTION.

From: FAA
To: NTSB
Date: 11/10/2015
Response: -From Michael P. Huerta, Administrator: A dedicated FAA and Aerospace Industry Association (AIA) working group updated the BRDB and re-evaluated the large Flocking bird certification requircn1ents of § 33.76(d). As noted in our previous letters, the final report of the AIA working group found that Class D size engines with inlet area less than 3,875 square inches are currently operating near the safety objective of the current rule, even though only 22 percent of engines represented in the updated database are designed to the latest regulations. The AIA found the same for core ingestion events. However, this class of engine is the most statistically significant bird risk category because it accrues the highest number of total flights within the transport category world fleet. The ARAC working group, therefore, considered large flocking bird species and specifically whether a new core ingestion requirement is necessary. The ARAC working group found that the existing medium flocking bird test, including the additional integrity requirement, is at least as stringent for this size engine as the large flocking bird test is for larger engines. In addition, the new climb condition medium flocking bird test proposed in our response to Safety Recommendation A-10-64 will fut1her assure the robustness of the engine core. For these reasons, the working group agrees that no new large nocking bird requirement is needed. I believe that the FAA has effectively addressed Safety Recommendation A- 10-65 and consider our actions complete.

From: NTSB
To: FAA
Date: 2/21/2014
Response: We note that a joint FAA and Aerospace Industry Association working group (1) completed its update of the BRDB, (2) reevaluated the large flocking bird certification requirements of Section 33.76(d), and (3) found that engines with an inlet area of less than 3,875 square inches are currently operating near the safety objective of the current rule and no further revisions are appropriate at this time. This completes part (1) of Safety Recommendation A-10-65. As part of its work described above in response to Safety Recommendation A-10-64, the ARAC will address part (2) by considering large flocking bird species and whether a new core ingestion requirement is necessary. Pending completion of part (2) of Safety Recommendation A-10-65, the recommendation remains classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 12/24/2013
Response: -From Michael P. Huerta, Administrator: As noted in our previous response, a dedicated FAA and Aerospace Industry Association (AIA) working group has completed its task to update the BRDB and to reevaluate the large flocking bird certification requirements of§ 33.76(d). The working group detem1ined whether the existing requirements could be relied upon to provide the intended level of safety over time with respect to the large flocking bird threat observed in service. In its final repot1, the AIA working group found that engines with an inlet area of less than 3,875 square inches are currently operating near the safety objective of the current rule. This class of engine statistically has the most significant bird risk because it accrues the highest number of total flights within the transport category world fleet. As part of the ongoing task, the ARAC working group (noted in the response to A-1 0-64) will consider large flocking bird species, and specifically, whether a new core ingestion requirement is necessary. The FAA believes our planned actions are consistent with the general intent of these recommendations and would help keep our engine type certification regulations relevant. I will keep the Board informed of the FAA's progress on these safety recommendations and provide an updated response by December, 2014.

From: NTSB
To: FAA
Date: 12/26/2012
Response: We note that the FAA working group has updated the BRDB and has reevaluated the large flocking bird certification requirements of 14 CFR 33.76(d). The FAA reported that Class D–size engines do not need to be included in the large flocking bird engine test requirements; however, it believes that additional conservatism within the type certification requirements would be wise. To address this concern, the FAA stated that it is considering a rulemaking project in 2012 that would identify a reasonable means to ensure that the world fleet of Class D engines meets the intended safety objective of the current rule. In addition, the FAA reported that a core ingestion test specific to large flocking birds is not necessary, but the FAA plans to strengthen the medium bird core ingestion element, which it believes will result in an increased core ingestion capacity for all bird threats. Pending our review of the FAA’s plan for ensuring that the world fleet of Class D engines meets the intended safety objective of the current rule, Safety Recommendation A-10-65 remains classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 8/24/2012
Response: -From Michael P. Huerta, Acting Administrator: A dedicated FAA and AIA working group has completed its task to update the BROB and to reevaluate the large flocking bird certification requirements of § 33 .76(d). The goal of the reevaluation was to determine whether the existing requirements can be relied upon to provide the intended level of safety over time with respect to the large flocking bird threat observed in service. The FAA has reviewed the working group interim report and has the following comments: 1. Class D size engines (inlet area less than 3,875 square inches) are currently operating near the safety objective of the currel1l rule. However, only 22 percent of engines represented in the updated database are designed to the latest regulations, while older engines are designed to less stringent requirements. The FAA expects that overall fleet capability and safety margins will increase markedly in the future as engines designed to the current rule become more prominent in the world fleet. Therefore, there is no current need to include this class engine in the large flocking bird engine test requirement. Nevertheless, this class of engine is the most statistically significant bird risk category because it accrues the highest number of total flights within the transport category world fleet. This is an important consideration as exposure to bird ingestion events primarily occurs during the takeoff and landing phases of flight. Based on these observation s, the FAA believes additional conservatism within the type certification requirements is prudent for these engines to ensure their continued acceptable performance in the future. Therefore, the FAA plans to initiate a rulemaking project in 2012 to identify a reasonable means to ensure that the world fleet of Class D engines meets the intended safety objective of the current rule. 2. Core ingestion of large flocking birds is a relatively small percentage of the overall risk of multi-engine power loss. Because power losses are predominately driven by fan blade fracture and damage, the current engine certification test is considered the best demonstration of overall engine capability against this threat. Also, previous rulemaking efforts revealed that fan ingestions make up the majority of related risk, and that the safety objective of the rule is met without a core ingestion test. Therefore, the FAA does not see the need to add a core ingestion test specific to large flocking birds. However, as discussed above, the FAA plans to initiate a rulemaking project in 2012 to revise and strengthen the medium bird core ingestion element of current § 33.76(c) to make future engine models more tolerant to the general core ingestion threat. Large flocking bird species will be considered in this rulemaking. The strengthened medium bird test will result in increased core ingestion capability for all bird threats. The FAA believes its planned act ions are consistent with the general intent of these recommendations and plans to keep its engine type certification regulations modern and relevant. I will keep the Board informed of the FAA's progress on these safety recommendations and provide an update by July 2013.

From: NTSB
To: FAA
Date: 1/10/2012
Response: The NTSB notes the continued efforts of the working group to evaluate these two recommendations, and we look forward to reviewing the group’s findings. Pending completion of that evaluation and appropriate FAA action to implement the recommended revision, Safety Recommendations A-10-64 and -65 remain classified OPEN—ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 10/4/2011
Response: From J. Randolph Babbitt, Administrator: A dedicated FAA and AIA working group was formed and is evaluating § 33.76(d). The Pat1 33 BROB was last updated in 2000. The latest update is nearing completion, and has added about 12,000 new bird ingestion records for the 2000-2009 time period. A preliminary review of the data shows that the in-service, multi-engine ingestion rates for this time period are not significantly greater than the rates from the 2000 data, and are close to the predicted rates for 2010. The current regulation is based on the predicted rates for 2010. Also, the new data shows that engine power loss rates for a given ingestion have generally improved over this time period. This is likely because the world-wide fleet now includes a greater number of newer, more capable engine models. These preliminary observations tell us that the overall large flocking bird threat has not significantly worsened in this time period. However, much work remains to determine whether the current regulation will continue to meet our overall safety objective or if new rulemaking, policy, or method of compliance guidance is required. I will keep the Board informed of the FAA's progress on these safety recommendations and provide an update by August 2012.

From: NTSB
To: FAA
Date: 3/17/2011
Response: The NTSB looks forward to reviewing the findings of the working group led by the FAA and the Aerospace Industries Association (AIA) that is evaluating these two recommendations. Pending completion of that evaluation and appropriate FAA action to implement the recommended revision, Safety Recommendations A-10-64 and -65 are classified OPEN – ACCEPTABLE RESPONSE.

From: FAA
To: NTSB
Date: 9/23/2010
Response: CC# 201000368: - From J. Randolph Babbitt, Administrator: The FAA/ AIA working group referenced in our response to recommendation A-10-64 will also re-evaluate § 33.76(d). New rulemaking, policy, or method of compliance guidance could result from this effort.