Source: https://ntsb.gov/safety/safety-recs/_layouts/ntsb.recsearch/Recommendation.aspx?Rec=A-04-056
Timestamp: 2019-08-24 03:03:43
Document Index: 444386403

Matched Legal Cases: ['art 121', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 25', 'art 121', 'art 121', 'arts 65', 'art 121', 'art 135', 'art 25', 'art 25', 'art 25']

Safety Recommendation A-04-056
Synopsis: On November 12, 2001, about 0916:15 eastern standard time, American Airlines flight 587, an Airbus Industrie A300-605R, N14053, crashed into a residential area of Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport, Jamaica, New York. Flight 587 was a regularly scheduled passenger flight to Las Americas International Airport, Santo Domingo, Dominican Republic, with 2 flight crewmembers, 7 flight attendants, and 251 passengers aboard the airplane. The airplane’s vertical stabilizer and rudder separated in flight and were found in Jamaica Bay, about 1 mile north of the main wreckage site. The airplane’s engines subsequently separated in flight and were found several blocks north and east of the main wreckage site. All 260 people aboard the airplane and 5 people on the ground were killed, and the airplane was destroyed by impact forces and a postcrash fire. Flight 587 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: Modify 14 Code of Federal Regulations Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity.
Location: Belle Harbor, NY, United States
Accident #: DCA02MA001
Accident Reports: In-Flight Separation of Vertical Stabilizer American Airlines Flight 587, Airbus Industrie A300-605R, N14053
Report #: AAR-04-04
Accident Date: 11/12/2001
Addressee(s) and Addressee Status: FAA (Open - Unacceptable Response)
Keyword(s): Rudder
Response: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration's (FAA) notice of proposed rulemaking (NPRM) titled, “Yaw Maneuver Conditions—Rudder Reversals,” which was published at 83 Federal Register 32807 on July 16, 2018. The proposed rule was prompted by accident and incident data showing that pilots sometimes make rudder reversals during flight, even though such reversals are unnecessary and discouraged by flight crew training programs. One such occurrence was the November 12, 2001, accident involving American Airlines flight 587, an Airbus A300-600-series airplane that crashed in Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport.1 The NTSB determined that the probable cause of that accident was, in part, the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer's unnecessary and excessive rudder pedal inputs. One of the recommendations issued as a result of our investigation was Safety Recommendation A-04-56, which asked the FAA to take the following action: Modify 14 Code of Federal Regulations Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. Safety Recommendation A-04-56 is currently classified “Open—Unacceptable Response” due to the FAA’s many delays in issuing this NPRM. Issuing a final rule based on the NPRM will likely satisfy Safety Recommendation A-04-56.
Response: We note that you continue to develop a notice of proposed rulemaking (NPRM) to address this recommendation. We understand that your rulemaking resources are limited and that some rulemaking projects respond to congressional direction and to NTSB safety recommendations; however, we are concerned because this recommendation is more than 12 years old and, after the NPRM has been published, the final rule must still be issued. Accordingly, pending our review of the published NPRM, Safety Recommendation A-04-56 is classified OPEN—UNACCEPTABLE RESPONSE.
Response: -From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) confirms that we are continuing to process the planned proposed rule under the revised title "Yaw Maneuver Capability." The intent of the rule remains to establish a new load condition that requires applicants to demonstrate fin strength in the presence of rudder reversals. Since our April 14, 2015, correspondence, our rulemaking schedule was delayed due to other rulemaking priorities. We now estimate publishing the notice of proposed rulemaking by late 2017. I will keep the Board informed of the FAA's progress on this recommendation and provide an update by July 31, 2017.
Response: We note that, in December 2013, you received the final report and recommendations of the Aviation Rulemaking Committee’s Flight Controls Harmonization Working Group (FCHWG) that you had formed to address this recommendation. We further note that, based on the working group’s recommendations, you have initiated rulemaking and expect to publish a notice of proposed rulemaking (NPRM) in May 2016. We have been concerned with the slow pace of your response to this recommendation. However, although the NPRM is not scheduled to be published until 11 1/2 years after we issued Safety Recommendation A-04-56, and the final rule is unlikely to be issued until almost 20 years after the American Airlines flight 587 accident, we believe that the rule, if adopted as proposed, will satisfy the recommendation. Accordingly, pending publication of the NPRM and final rule as proposed, Safety Recommendation A-04-56 remains classified OPEN—ACCEPTABLE RESPONSE.
Response: From CC# 201500244: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM), titled “Airworthiness Directives; Airbus Airplanes,” which was published at 80 Federal Register 11960 on March 5, 2015. The NPRM proposes to adopt a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This proposed AD would require modification of the pin programming of the flight warning computer (FWC) to activate the stop rudder input warning (SRIW) logic, an inspection to determine the part numbers of the FWC and the flight augmentation computer (FAC), and replacement of the FWC and FAC if necessary. The FAA is proposing this AD to prevent detachment of the vertical tail plane and consequent loss of control of the airplane. This proposed AD was prompted by a determination that, in specific flight conditions, the allowable load limits on the vertical tail plane could be reached and possibly exceeded, which could result in detachment of the vertical tail plane. The proposed AD results, in part, from in service incidents involving Airbus A319 and A320 models. On January 10, 2008, about 0848 central standard time, Air Canada flight 190, an Airbus A319, Canadian registration C-GBHZ, experienced a sudden in-flight upset after encountering wake turbulence from a 747 while climbing from flight level (FL) 360 to FL370. With the autopilot on, the airplane initially rolled 28° to the left and then rolled back to 10° to the right. A series of large oscillatory inputs on the lateral and longitudinal side-stick controller and on the rudder pedals followed. During these inputs, the airplane continued to oscillate in roll, achieving roll angle peaks of up to 56° left and 37° right before returning to level flight. At the same time, the lateral load factor also underwent large oscillations, with peaks from -0.46G to +0.49G. The vertical load factor achieved peaks from -0.77G to 1.57G. The airplane lost about 1,000 ft of altitude during the upset. The flight crew declared an emergency and diverted the flight to Calgary, where it landed uneventfully. Of the 5 crew members and 83 passengers on board, 2 crew members and 8 passengers sustained minor injuries. In addition, the proposed AD results from Safety Recommendations A 04 56 through 58, which the NTSB issued after its investigation of a November 12, 2001, accident involving American Airlines flight 587, an Airbus Industrie A300-605R, N14053, which crashed into a residential area of Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport, Jamaica, New York. Following an encounter with wake turbulence from a preceding 747 and a series of alternating rudder pedal inputs by the first officer, the airplane’s vertical stabilizer and rudder separated in flight and were found in Jamaica Bay, about 1 mile north of the main wreckage site. All 260 people aboard the airplane and 5 people on the ground died, and the airplane was destroyed by impact forces and a postcrash fire. As a result of this accident, the NTSB issued several recommendations, including the following recommendations to the FAA: Modify 14 Code of Federal Regulations Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. (A-04-56) After the yaw axis certification standard recommended in Safety Recommendation A-04-56 has been established, review the designs of existing airplanes to determine if they meet the standard. For existing airplanes designs that do not meet the standard, the FAA should determine if the airplanes would be adequately protected from the adverse effects of a potential aircraft-pilot coupling (APC) after rudder inputs at all airspeeds. If adequate protection does not exist, the FAA should require modifications, as necessary, to provide the airplanes with increased protection from the adverse effects of a potential APC after rudder inputs at high airspeeds. (A-04-57) Review the options for modifying the Airbus A300-600 and the Airbus A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds and, on the basis of this review, require modifications to the A300 600 and A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds. (A-04-58) In response to Safety Recommendation A-04-58, on November 9, 2012, the FAA published AD 2012-21-15 for all Airbus A300-600 and Airbus A310 series airplanes. The AD requires either incorporating a design change to the rudder control system and/or other systems or installing an SRIW modification to prevent loads on the vertical stabilizer that exceed ultimate design loads. The NTSB has noted its concerns about a warning light alone to address issues with the yaw control and rudder system. When the FAA proposed the SRIW in a May 19, 2011, NPRM, we submitted comments on July 5, 2011, stating our concern that a warning light alone will not rectify the unsafe condition identified in the NPRM. We reiterated this concern in a February 4, 2013, letter to the FAA regarding Safety Recommendation A-04-58. However, we noted that the SRIW and other design modifications would likely increase protection from potentially hazardous rudder pedal inputs at high airspeeds and classified Safety Recommendation A-04-58 “Closed—Acceptable Action.” Although the A320 SRIW is named similarly to the A300/A310 SRIW and each has an aural component, we note that the NPRM and European Aviation Safety Agency (EASA) AD 2014-0217, on which the NPRM is based, do indicate differences. For example, the A300/A310 SRIW has a glare shield red warning lamp that lights when the SRIW is activated; the NPRM and EASA AD do not mention a warning light as part of the A320 SRIW. More importantly, however, we also note that the A320 SRIW incorporates some measure of vertical tail “protection” or unloading based on FAC modification. As stated in EASA AD 2014 0217, “Airbus has developed modifications within the flight augmentation computer (FAC) to reduce the vertical tail plane stress and to activate a conditional aural warning within the flight warning computer (FWC) to further protect against pilot induced rudder doublets” (emphasis added). However, neither the NPRM nor the EASA AD mentions specific details of this aspect of the SRIW. Without these details, we cannot fully assess the A320 SRIW’s responsiveness to Safety Recommendations A-04-56 and -57. We anticipate that the FAA has fully analyzed the SRIW with respect to these safety recommendations as well as the future criteria for Part 25 yaw control changes. However, we cannot determine whether the A320 SRIW includes a warning light like the A300 SRIW or whether it has more comprehensive protection, and we encourage the FAA to address these details in the final rulemaking. The NTSB appreciates the opportunity to comment on the information that is contained in this NPRM and looks forward to receiving additional information and clarification on the issues presented.
Response: -From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) tasked the Aviation Rulemaking Advisory Committee Flight Controls Harmonization Working Group (FCHWG) to address Safety Recommendation A-04-56. In December of2013, the FCHWG completed their work and sent a final report with FCHWG recommendations to the FAA. Based on the FCHWG's recommendations, the FAA initiated rulemaking that will address Safety Recommendation A-04-56. If adopted, the proposed rule would require type certificate applicants to show that their airplanes are protected from loads induced by pi lot commanded pedal reversals, sometimes called doublets. This proposed rule would be performance based, and type certificate applicants could comply in several ways. We expect most applicants will use control laws or system architecture. These methods ensure that the airplane will not reach sideslip angles where rudder commands can induce high fin loads. These methods also reduce the airplane sensitivity to pedal commands. The proposed rule should prevent future occurrences of high fm loads that we have seen in the past, including those in the American Airlines flight 587 accident. We expect to issue a Notice of Proposed Rulemaking (NPRM) in May 2016.
Response: The FAA previously indicated that it had completed a five-part study of the issues associated with rudder usage on transport airplanes. On March 28, 2011, the FAA published a Federal Register notice concerning the formation of, and expected results from, a new Aviation Rulemaking Advisory Committee (ARAC) task developing recommendations for new standards and guidance addressing safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. Among the specific issues to be addressed by the ARAC were revisions to Part 25 in response to Safety Recommendation A-04-56, the application of the new standards to in-service aircraft, and requirements for possible revisions to in-service aircraft as recommended in Safety Recommendation A-04-57. In its June 17, 2011, letter, the FAA stated that the ARAC was scheduled to finish its work in August 2012. In its current letter, the FAA indicated that the ARAC’s Flight Controls Harmonization Working Group (FCHWG) met for the first time in December 2011 and is now expected to release its report in February 2013. We have previously stated that the five-part study was a positive step in addressing these recommendations, but we were concerned about the slow pace of the FAA’s actions. It took seven years to complete the five-part study, and only now has the ARAC started to make recommendations to revise the appropriate certification standards. The scheduled date for completion of that work has now slipped by six months to March 2013, after which the FAA will still have several years of work before revisions to the standards will be complete, followed by several more years work to analyze in-service aircraft and require revisions where needed. Despite these concerns, however, pending appropriate revisions being made to the certification standards based on the five-part study, Safety Recommendation A-04-56 remains classified OPEN—ACCEPTABLE RESPONSE. Also, despite the same concerns, pending the application of all criteria developed as a result of the five-part study to existing airplane designs and appropriate actions being taken for airplane designs that do not meet the new standards, Safety Recommendation A-04-57 remains classified “Open—Acceptable Response.”
Response: -From Michael P. Huerta, Acting Administrator: The FAA -sponsored Aviation Rulemaking Advisory Committee Flight Controls Harmonization Working Group (FCHWG) met in December 2011 and again in February 2012. Because the first FCHWG meeting was delayed until December 2011, due to the formation of the working group, their report is now expected to be released in February 2013. We expect to use the report to develop new advisory material and if necessary, initiate new rulemaking.
Response: The FAA has completed its five-part study to better understand the issues associated with rudder usage on transport airplanes and has now tasked the Aviation Rulemaking Advisory Committee (ARAC) with developing recommendations for new standards and guidance addressing safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. The NTSB reviewed the March 28, 2011, Federal Register notice concerning the formation and expected results from the new ARAC task. Among the specific issues that will be addressed by the ARAC are revisions to Part 25 in response to Safety Recommendation A-04-56, the application of the new standards to in-service aircraft, and requirements for possible revisions to in-service aircraft as recommended in Safety Recommendation A-04-57. The NTSB has previously stated that the five-part study is responsive to this recommendation, and its completion 7 years after these recommendations were issued represents progress. The FAA briefed NTSB staff on the study as it progressed, and those briefings indicated that the study would be comprehensive; accordingly, now that it has been completed, we request available copies of any reports about the study and its results for our review. The NTSB is concerned about the slow pace of the FAA’s response to these recommendations. As stated above, it took 7 years to complete the five-part study, and only now has the ARAC started to make recommendations to revise the appropriate certification standards. That work is scheduled for completion in August 2012, after which the FAA will still have several years of work before revisions to the standards will be complete, followed by several more years work to analyze in-service aircraft and require revisions where needed. Nevertheless, despite our concern over the FAA’s slow pace, pending appropriate revisions being made to the certification standards based on the five-part study, Safety Recommendation A-04-56 remains classified OPEN—ACCEPTABLE RESPONSE. Also, despite the same concern, pending the application of all criteria developed as a result of the five-part study to existing airplane designs and appropriate actions being taken for airplane designs that do not meet the new standards, Safety Recommendation A-04-57 remains classified “Open—Acceptable Response.”
Response: Notation 8322: The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM) titled “Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and Model C4-605R, Variant F Airplanes (Collectively Called A300-600 Series Airplanes); and Model A310 Series Airplanes,” which was published in 76 Federal Register 28914 on May 19, 2011. The NPRM proposes a new airworthiness directive (AD) for Airbus A300-600 series and A310 series airplanes. The proposed AD would require actions to address excessive rudder pedal inputs and the consequent high loads on the vertical stabilizer. It would also address the higher rudder pedal sensitivity in these airplanes than other transport-category airplane designs, which could result in rudder overcontrol and contribute to hazardous rudder inputs, such as rudder reversals. The proposed AD results from safety recommendations issued by the NTSB following the investigation of the November 12, 2001, accident involving American Airlines flight 587, an Airbus Industrie A300-605R, N14053, which crashed into a residential area of Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport, Jamaica, New York. Following an encounter with wake turbulence from a preceding Boeing 747 and a series of alternating rudder pedal inputs by the first officer, the airplane’s vertical stabilizer and rudder separated in flight and were found in Jamaica Bay, about 1 mile north of the main wreckage site. All 260 people aboard the airplane and 5 people on the ground were killed, and the airplane was destroyed by impact forces and a postcrash fire. Further, the NTSB is aware of other events of a similar nature. One event, during stall recovery in an A300-600 airplane, resulted in alternating rudder pedal inputs, high vertical stabilizer loads and serious injury to one passenger among the 165 persons on board. Another incident, during stall recovery after an aborted landing attempt in an A310 airplane operated by a German airline, resulted in alternating rudder inputs and high vertical stabilizer loads that exceeded the ultimate design loads. Among the recommendations the NTSB issued to the FAA as a result of the American Airlines flight 587 accident investigation were the following: Modify 14 Code of Federal Regulations Part 25 standards to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. (A 04-56) After the yaw axis certification standard recommended in Safety Recommendation A-04-56 has been established, review the designs of existing airplanes to determine if they meet the standard. For existing airplane designs that do not meet the standard, the FAA should determine if the airplanes would be adequately protected from the adverse effects of a potential aircraft-pilot coupling (APC) after rudder inputs at all airspeeds. If adequate protection does not exist, the FAA should require modifications, as necessary, to provide the airplanes with increased protection from the adverse effects of a potential APC after rudder inputs at high airspeeds. (A-04-57) Review the options for modifying the Airbus A300-600 and the Airbus A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds and, on the basis of this review, require modifications to the A300 600 and A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds. (A-04-58) The NTSB is encouraged that various actions, as indicated in the proposed rulemaking, are under consideration but is concerned that the rulemaking does not appear to propose a definitive fix of the rudder system; the rulemaking mentions the pedal traveler limiter unit (PTLU) but notes that it is just one option that is currently under review to address excessive rudder pedal inputs. The exact details of the proposed PTLU fix have not yet been documented, and, without a careful review of the proposed modification, the NTSB is unable to determine to what extent it might provide protection from the adverse effects of APC issues in rudder system use, as recommended. In addition, the NTSB notes that the FAA anticipates approving a design change that meets the proposed requirements within the next 3 years and that operators would be required to take action within 4 years of the rulemaking. It is unfortunate that almost 10 years after the Belle Harbor accident, no design change has yet been made available to operators. Finally, the NTSB understands that a warning light for the flight deck that does not incorporate any mechanical changes to the rudder system is under development by Airbus. The NTSB is concerned that a warning light alone will not rectify the unsafe condition identified in the NPRM. The NTSB would appreciate any information regarding cooperation between the FAA and the European Aviation Safety Agency on this matter. It is encouraging that industry and the FAA are exploring options for addressing excessive rudder inputs, and the NTSB supports the intent of this NPRM, as well as the underlying industry work to provide increased protection against APC issues in the rudder input of A300-600 series and A310 series airplanes. We remain concerned, however, about the lack of specificity and the length of time it is taking to make a design change available to operators. The NTSB appreciates the opportunity to comment on this NPRM.
Response: CC#201100255: - From J. Randolph Babbitt, Administrator: The FAA Five Part Rudder Study to better understand the issues associated with rudder usage on transport airplanes is complete. This study enabled the FAA to appropriately task the Aviation Rulemaking Advisory Committee (ARAC), which includes industry and foreign certification authorities, to develop recommendations for new standards and guidance. The Aviation Rulemaking Advisory Comn1ittee; Transport Airplane and Engine Issues-New Task (enclosure 2), was published on March 28, 2011, in the Federal Register, and the first meeting of the ARAC is anticipated to occur before July 2011. The ARAC report is scheduled to be completed by August 2012. The ARAC has also been tasked to consider possible revisions to part 25 that addresses Safety Recommendation A-04-56, and will be examining modification options for Safety Recommendation A-04-57.
Response: The NTSB appreciates receiving the table summarizing the preliminary results of the FAA’s five-part study of the issues associated with rudder usage on transport airplanes. On January 14, 2010, the FAA briefed NTSB staff on its activities in response to the recommendations issued as a result of the AA587 accident. The five-part study, which is responsive to this recommendation, was discussed at that briefing. The NTSB notes that, as an interim action since the AA587 accident, the FAA has required applicants for type certification of large transport category airplanes to address oscillatory rudder pedal inputs. On August 3, 2010, the NTSB sent the FAA a letter reiterating Safety Recommendations A-04-56 and -57, prompted by our participation in the Transportation Safety Board (TSB) of Canada’s investigation of the January 10, 2008, in-f1ight upset after encountering wake turbulence of Air Canada flight 190 (ACA190), an Airbus A319. The circumstances of the two accidents are similar. The investigation of the ACA190 accident revealed a series of three to four alternating rudder pedal inputs over 15 seconds in response to the upset. Because of the severity of the upset, following the airplane’s emergency landing at Calgary, it was grounded pending an inspection by Airbus engineers. Although no damage to the stabilizer was found, an Airbus’s analysis of the accident indicated that the attachment fitting of the rear vertical stabilizer had sustained loads that were 29 percent above its design limit load. Simulation work performed by Airbus revealed that these high loads were primarily the result of the flight crew’s series of alternating rudder pedal inputs. In reiterating Safety Recommendations A-04-56 and -57, we stated The similarities between the Air Canada flight 190 and American Airlines flight 587 crewmembers’ responses to wake encounters indicate that the Airbus A320 family is also susceptible to potentially hazardous rudder pedal inputs at higher airspeeds. In both events, the vertical stabilizer limit loads were exceeded by a large margin as a result of the alternating rudder inputs. In the Air Canada flight 190 accident, the pilot applied three alternating rudder inputs and exceeded the limit load by 29 percent. In the American Airlines flight 587 accident, the pilot applied four full alternating rudder inputs; after the fourth input, the aerodynamic loads on the vertical stabilizer exceeded the vertical stabilizer’s ultimate design load (at about twice the maximum load), and it separated from the airplane. The Air Canada flight 190 accident demonstrates that the need remains to revise the certification standards for transport-category aircraft regarding yaw sensitivity to rudder pedal inputs and that these revised standards need to be applied to current in-service aircraft. As discussed above, the Airbus A320 rudder control system design characteristics are comparatively similar to those of the Airbus A300-600 and A310 and may serve as a trigger for an APC event at high airspeeds. The NTSB believes that the yaw axis handling qualities standard envisioned by Safety Recommendation A-04-56 will preclude such characteristics. Further, the NTSB notes that, if the FAA had performed the review of existing airplane designs as asked for in Safety Recommendation A-04-57 to see if they meet new yaw characteristic standards developed for A-04-56, the FAA may have noted that the A320 airplane also needed increased protection from potentially hazardous rudder inputs at high airspeeds. Therefore, the NTSB reiterates Safety Recommendations A-04-56 and -57. Based on information available to the NTSB, the five-part study is responsive to these recommendations; when it is completed and appropriate revisions have been made to the certification standards regarding handling qualities in the yaw axis, the FAA will have met the intent of Safety Recommendation A-04-56. The NTSB also believes that the certification requirement for new type certificates to address oscillatory rudder pedal inputs is an effective interim action. The NTSB reemphasizes, however, the point we made when these recommendations were reiterated on August 3, 2010: because of the similarity of the rudder control system designs of the A320 series and A300-600/A310 aircraft, the A320 family is also susceptible to potentially hazardous rudder pedal inputs, as demonstrated in the ACA190 event. The five-part study may not meet the original intent of Safety Recommendation A-04-56 unless the study recognizes these similarities and addresses the potential for hazardous rudder pedal inputs on the A320 series of aircraft. Accordingly, pending completion of the five-part study and appropriate revisions being made to the certification standards based on the study and the findings of the American Airlines flight 587 and Air Canada flight 190 accident investigations, Safety Recommendation A-04-56 remains classified OPEN – ACC EPTABLE RESPONSE. Pending the application of all criteria developed as a result of the five-part study to existing airplane designs and appropriate actions being taken for airplane designs that do not meet the new standards, Safety Recommendation A-04-57 remains classified “Open—Acceptable Response.”
Response: CC# 201100047 - From Patrick Goudou, Executive Director, European Aviation Safety Agency: This letter is from the European Aviation Safety Agency (EASA). EASA notes the FAA initial response to A-04-56 and -57 in which the FAA indicated that the current standards in FAR Part 25 may need to be redefined and that it was evaluating these and conducting a study to identify critical rudder control system parameters and human interaction with those controls. EASA acknowledges that such a study is appropriate and we would be willing to work with the FAA to develop the research already conducted in order to determine whether and how existing certification standards could be revised. When the study concludes that Certification Standards need to be revised, a new task will be introduced in the EASA rulemaking programme and it will be developed following the usual rulemaking procedure, which includes a regulatory impact assessment to set the priority and schedule, and the best harmonisation with the FAA. At this stage it is worth noting that our general objective, when amending existing or developing new certification standards, is to identify clearly the safety objective to be met by the applicant and wherever possible to avoid making the standards too prescriptive. With this in mind, our general approach to this particular subject would be to consider the pilot, flight control and aircraft interactions, including the structural capability of the airframe to withstand an abuse case, rather than to focus too closely on specific parameters within an individual control circuit design. Regarding progress on the development of the reduced pedal travel limiter unit for the A300-600 and A310, EASA has received an overall engineering certification and embodiment programme from Airbus, which shows that such a solution will take several years to develop, certify and embody. Airbus has in parallel proposed a new alternative design which is aimed at de-coupling the pilot input. Airbus has included in its proposal a development, certification and embodiment plan which is considerably shorter than for the R-PTLU. The new design monitors rudder input parameters and triggers flight deck visual and aural warnings, which would require the pilot to release the pedals, thus preventing an escalation of the coupling. EASA is carefully evaluating the new concept and has started the certification process of the associated design change, in coordination with the FAA. In respect of the A320 family, which is mentioned in the NTSB letter, EASA has previously acknowledged that there are some similarities between the Air Canada flight 190 event and the American Airlines flight 587 accident; both were triggered by a wake vortex encounter at high airspeed. It is however important to restate that the crew reactions were very different. In the AC 190 event the crew inputs combined side-stick and pedals were not aggressive whereas in the AA587 accident the crew reaction reflected the negative training from the AAMP. This difference indicates to us that if a crew is caught unaware in a wake vortex encounter there is a possibility that they would react by making control inputs, but they would not necessarily make repetitive aggressive inputs. Consistent with our approach to the rulemaking review, we have tasked Airbus with conducting an aircraft level evaluation of the A320 design to ensure that the design as a whole is robust enough to withstand such a low probability event.
Response: CC# 201100010: - From J. Randolph Babbitt, Administrator: We conducted a five-part study to better understand the issues associated with rudder usage on transport airplanes. Summarizing this study, the Outline of the FAA Five Part Rudder Study (enclosure 2) describes the parts and the preliminary results and conclusions drawn from the study. A determination of how to address this recommendation will be made when this study is complete, which is projected to occur by April 2011. It is important to note that since the American Airlines flight 587 accident, applicants for type certification of large transport category airplanes must address oscillatory pedal inputs. Most applicants chose to address this issue through the design of their rudder control system control laws. I will keep the Board informed of the FAA's progress on this safety recommendation, and I will provide an update by April 2011.
Response: Notation 8216: On November 12, 2001, about 0916 eastern standard time, an Airbus A300-605R, N14053, operated as American Airlines flight 587, crashed into a residential area of Belle Harbor, New York, shortly after takeoff from John F. Kennedy International Airport, Jamaica, New York. Following an encounter with wake turbulence from a preceding Boeing 747 (747), the first officer made a series of full alternating rudder pedal inputs before the airplane’s vertical stabilizer and rudder separated in flight; both were found in Jamaica Bay about 1 mile north of the main wreckage site. The National Transportation Safety Board (NTSB) determined that the probable cause of the American Airlines flight 587 accident was the in-flight separation of the vertical stabilizer as a result of the loads beyond ultimate design that were created by the first officer’s unnecessary and excessive rudder pedal inputs. Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program (AAMP). The circumstances of the American Airlines flight 587 accident are similar to a more recent accident involving an Airbus model A319. On January 10, 2008, about 0848 central standard time, an Airbus Industrie A319, Canadian registration C-GBHZ, operated as Air Canada flight 190, experienced an in-flight upset after encountering wake turbulence from a 747 while climbing from flight level (FL) 360 to FL370. The flight crew declared an emergency and diverted the flight to Calgary, where it landed uneventfully. Of the 5 crewmembers and 83 passengers on board, 2 crewmembers and 8 passengers sustained minor injuries, and 3 passengers sustained serious injuries. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed for the scheduled domestic passenger flight from Victoria International Airport, British Columbia, Canada, to Toronto Pearson International Airport, Ontario, Canada. The Transportation Safety Board of Canada (TSB) investigated this accident; the NTSB and Bureau d’Enquêtes et d’Analyses provided accredited representatives and technical advisors to the investigation. Data from the flight data recorder (FDR) indicate that, during the upset, the airplane experienced several roll and vertical load factor oscillations and lost about 1,000 feet of altitude. Although the autopilot was engaged during the start of the wake vortex encounter, after about 3 seconds, the autopilot was disengaged, and there was a series of large oscillatory inputs on the left side stick controller. In addition, the FDR recorded a series of three to four alternating rudder pedal inputs (right pedal, then left pedal) over the next 15 seconds. During these inputs, the airplane continued to oscillate in roll, reaching a maximum roll of 55º. At the same time, the recorded acceleration was also oscillating, with peaks of -0.46 G to +0.49 G of lateral load factor and peaks of -0.76 G to +1.57 G of vertical load factor. Because of the severity of the upset, following the emergency landing at Calgary, the airplane was grounded pending an inspection by Airbus engineers. During an extensive inspection, the vertical stabilizer was removed from the airplane and scanned ultrasonically to inspect for damage to the stabilizer’s composite components. No damage was found, and the stabilizer was reattached and the airplane returned to service. Although no damage to the stabilizer was found, an analysis of the accident performed by Airbus indicated that the rear vertical stabilizer attachment fitting sustained loads 29 percent above its design limit load. Simulation work performed by Airbus revealed that these high loads were primarily the result of the flight crew’s series of alternating rudder pedal inputs and were not the result of the wake turbulence. Information and animations provided by Airbus showed that if the pilots had not made any control inputs after the wake encounter, the airplane would have righted itself with minimum altitude loss and g-loading. Pilot Rudder Pedal Inputs, Yaw Axis Certification, and Rudder Pedal Sensitivity In both the American Airlines flight 587 and Air Canada flight 190 accidents, the vertical stabilizer limit loads were exceeded by a large margin as a result of the alternating full scale rudder inputs. The NTSB’s investigation of the American Airlines flight 587 accident revealed that the Airbus A320 airplane family, which includes the A319, and the Airbus A300/A310 airplane family both use a variable-stop rudder travel limiter, which mechanically limits available rudder pedal deflection as airspeed increases. Consequently, at high airspeeds, these systems require lighter pedal forces and smaller pedal displacements to obtain maximum available rudder than at low airspeeds. Investigation of the American Airlines flight 587 accident revealed that variable-stop systems produce dramatically larger aircraft responses to the same rudder input at higher airspeeds than at lower airspeeds, which can surprise a pilot and serve as a trigger for an aircraft pilot coupling (APC) event. As a result of findings from the American Airlines flight 587 investigation, the NTSB issued Safety Recommendation A-04-58, which asked the Federal Aviation Administration (FAA) to do the following: Review the options for modifying the Airbus A300-600 and the Airbus A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds and, on the basis of this review, require modifications to the A300 600 and A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds. In the same report, the NTSB issued a companion recommendation, A-04-63, to the French Direction Générale de l’Aviation Civile. On April 6, 2009, the European Aviation Safety Agency (EASA) indicated that Airbus is developing a reduced pedal travel limiting unit (PTLU). On March 19, 2010, EASA further indicated that “its previously held position on the pilot training out as being an efficient and sufficient measure to avoid any new hazardous situations has to be reconsidered following more recent service experience which confirms that crew use of rudder pedal inputs in upset encounters cannot be ‘trained out.’” EASA therefore indicated that it plans to require the PTLU on Airbus A310 and A300-600 aircraft models. The NTSB will consider how the proposed changes are responsive to Safety Recommendation A 04 58 when the FAA provides further details about the PTLU. In the report on the American Airlines flight 587 accident, the NTSB also issued Safety Recommendations A-04-56 and -57, which asked the FAA to do the following: Modify 14 Code of Federal Regulations [CFR] Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. (A-04-56) After the yaw axis certification standard recommended in Safety Recommendation A-04-56 has been established, review the designs of existing airplanes to determine if they meet the standard. For existing airplane designs that do not meet the standard, the FAA should determine if the airplanes would be adequately protected from the adverse effects of a potential [APC] after rudder inputs at all airspeeds. If adequate protection does not exist, the FAA should require modifications, as necessary, to provide the airplanes with increased protection from the adverse effects of a potential APC after rudder inputs at high airspeeds. (A-04-57) On March 1, 2005, the FAA indicated that the current standards governing the performance and design of yaw control systems may need to be redefined. The FAA added that it was evaluating the existing standards and conducting a study to identify critical rudder control system parameters and human interaction with those controls. The FAA further indicated that, based on the results of the study, it would determine whether the current standards need to be updated and would work with industry to develop rudder control standards. On August 3, 2005, the NTSB classified Safety Recommendations A-04-56 and -57 “Open—Acceptable Response.” The similarities between the Air Canada flight 190 and American Airlines flight 587 crewmembers’ responses to wake encounters indicate that the Airbus A320 family is also susceptible to potentially hazardous rudder pedal inputs at higher airspeeds. In both events, the vertical stabilizer limit loads were exceeded by a large margin as a result of the alternating rudder inputs. In the Air Canada flight 190 accident, the pilot applied three alternating rudder inputs and exceeded the limit load by 29 percent. In the American Airlines flight 587 accident, the pilot applied four full alternating rudder inputs; after the fourth input, the aerodynamic loads on the vertical stabilizer exceeded the vertical stabilizer’s ultimate design load (at about twice the maximum load), and it separated from the airplane. In a January 14, 2010, meeting, the FAA informed NTSB staff that the study of rudder control systems was complete and should be published in the first half of 2010. Furthermore, the FAA indicated that, as a result of the study, it may initiate rulemaking to revise certification standards for large airplane yaw control systems. The NTSB looks forward to the opportunity to review the results of the study and to further FAA action to develop yaw axis handling qualities standards as envisioned in Safety Recommendation A-04-56. The Air Canada flight 190 accident demonstrates that the need remains to revise the certification standards for transport-category aircraft regarding yaw sensitivity to rudder pedal inputs and that these revised standards need to be applied to current in-service aircraft. As discussed above, the Airbus A320 rudder control system design characteristics are comparatively similar to those of the Airbus A300-600 and A310 and may serve as a trigger for an APC event at high airspeeds. The NTSB believes that the yaw axis handling qualities standard envisioned by Safety Recommendation A-04-56 will preclude such characteristics. Further, the NTSB notes that, if the FAA had performed the review of existing airplane designs as asked for in Safety Recommendation A-04-57 to see if they meet new yaw characteristic standards developed for A 04-56, the FAA may have noted that the A320 airplane also needed increased protection from potentially hazardous rudder inputs at high airspeeds. Therefore, the NTSB reiterates Safety Recommendations A-04-56 and -57. Because of the FAA’s delay in responding to Safety Recommendation A-04-56, which asked the FAA to modify 14 CFR Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity, the NTSB is uncertain that the PTLU that Airbus is developing in response to A-04-58 will ensure that the A300/A310 airplanes will pass any yaw characteristic standards that the FAA develops. Because of the amount of time that has passed since the issuance of A-04-58 and the limited work that has been accomplished to date, the NTSB reiterates Safety Recommendation A-04-58. Pilot Training for Upset Recovery As a result of the Air Canada flight 190 accident investigation, on November 18, 2008, the TSB issued Aviation Safety Advisory A08W0007 D1 A1, “Pilot Training for Upset Recovery in Transport Category Aircraft,” to Transport Canada. In the advisory letter, the TSB noted that the accident “pilots were exposed to the material contained in the Airbus Flight Crew Operations (FCOM) No. 828/1” during Air Canada’s initial type training and recurrent ground school instruction every 24 months. However, although the pilots received upset training in the simulator, according to the letter, the training “concentrated on recovery from unusual attitudes in the pitch axis, with limited attention to proper rudder pedal usage during recoveries from large roll axis excursions.” The letter concluded by indicating that “Transport Canada may wish to communicate to transport category operators in Canada, the necessity to include roll scenarios in upset training and the appropriate use of rudder control during recoveries.” The NTSB has advocated upset recovery training since it issued Safety Recommendation A-96-120 on October 18, 1996, asking the FAA to do the following: Require 14 CFR Part 121 and 135 operators to provide training to flight crews in the recognition of and recovery from unusual attitudes and upset maneuvers, including upsets that occur while the aircraft is being controlled by automatic flight control systems, and unusual attitudes that result from flight control malfunctions and uncommanded flight control surface movements. On August 11, 1999, the FAA indicated that it was developing a notice of proposed rulemaking (NPRM) to revise 14 CFR Part 121, subparts N and O, to include training in recognition and recovery from unusual attitudes and upset maneuvers. However, by October 26, 2004, the FAA had not yet issued the NPRM and was unable to indicate when it would be published. Because of the lack of progress towards requiring air carrier pilots to participate in unusual attitude training, the NTSB reclassified Safety Recommendation A 96 120 “Open—Unacceptable Response.” On January 12, 2009, the FAA issued an NPRM titled “Qualification, Service, and Use of Crewmembers and Aircraft Dispatchers” to revise 14 CFR Parts 65, 119, 121, 135, and 142. The NTSB reviewed this NPRM and, on May 7, 2009, provided comments to the FAA. The NTSB noted that, in response to Safety Recommendation A 96 120, the NPRM includes training on recognizing and recovering from “special hazards,” which are sudden or unexpected aircraft upsets. The NTSB noted that this proposal would also include a requirement giving FAA principal operations inspectors (POIs) the authority to review and require changes to training programs that do not adequately address a special hazard. Lack of such authority was a concern identified during the American Airlines flight 587 accident investigation, in which the NTSB learned that the POI knew that aspects of the American Airlines training program had undesirable effects but lacked the authority to require American Airlines to change its program. In addition, the NPRM addresses recovery from loss of control due to airplane design, airplane malfunction, human performance, and atmospheric conditions. The “Upset Recognition and Recovery” section of the NPRM lists a number of items that should be covered, including noting that catastrophic damage may result from rapidly alternating full flight control inputs and that, on some airplanes, progressively lighter pedal forces and smaller pedal movements will command the maximum rudder deflection as speed increases. The NTSB notes that although this NPRM is responsive to Safety Recommendation A-96-120, it proposes requirements for Part 121 operators only; similar action for Part 135 operators will be needed before the recommendation can be closed. The FAA plans to issue the final rule in 2010. Early in its investigation of the American Airlines flight 587 accident, the NTSB determined that the first officer’s series of full alternating rudder pedal inputs resulted in excessive loads on the airplane’s vertical stabilizer and rudder, leading to their in-flight separation. As a result, on February 8, 2002, the NTSB issued Safety Recommendation A-02-01, which asked the FAA to do the following: Require the manufacturers and operators of transport-category airplanes to establish and implement pilot training programs that: (1) explain the structural certification requirements for the rudder and vertical stabilizer on transport category airplanes; (2) explain that a full or nearly full rudder deflection in one direction followed by a full or nearly full rudder deflection in the opposite direction, or certain combinations of sideslip angle and opposite rudder deflection can result in potentially dangerous loads on the vertical stabilizer, even at speeds below the design maneuvering speed; and (3) explain that, on some aircraft, as speed increases, the maximum available rudder deflection can be obtained with comparatively light pedal forces and small pedal deflections. The FAA should also require revisions to airplane and pilot operating manuals that reflect and reinforce this information. In addition, the FAA should ensure that this training does not compromise the substance or effectiveness of existing training regarding proper rudder use, such as during engine failure shortly after takeoff or during strong or gusty crosswind takeoffs or landings. On April 15, 2002, the FAA stated that it reviewed several Airbus operators’ training programs and found that none of the operators conduct training on the rudder in a way that could result in dangerous combinations of sideslip angles and rudder position. The FAA also indicated that it issued a notice directing POIs to notify their air carriers that sequential full opposite rudder inputs may result in structural loads that exceed those addressed by the 14 CFR Part 25 requirements; that the rudder limiter systems installed on most transport-category airplanes will not prevent sequential full opposite rudder deflections from damaging the structure; and that on some airplane types, full available rudder deflections can be achieved with small pedal movements and comparatively light pedal forces. The FAA stated that manufacturers would prepare and distribute to their operators flight technical operations bulletins that address the concerns of this recommendation. Finally, the FAA indicated that it was considering implementing the changes in the approved sections of the airplane flight manuals (AFM) of affected aircraft by the airplane manufacturers. On July 22, 2002, the NTSB responded that the FAA’s plan to use nonregulatory means to meet the intent of Safety Recommendation A-02-01 might represent an acceptable alternative; however, the NTSB would assume, until the FAA indicated otherwise, that the FAA would develop some regulatory changes in pilot training programs in response to Safety Recommendation A 02 01. Pending completion of changes to pilot training programs and the determination of whether these revisions will be implemented through AFM and technical operations bulletin changes or through regulatory changes, Safety Recommendation A-02-01 was classified “Open—Acceptable Response.” However, in the 8 years since the FAA’s April 15, 2002, letter, the FAA has not provided any additional information about its activities in response to Safety Recommendation A-02-01. The NTSB notes that the January 12, 2009, NPRM is partially responsive to the requirement to explain that catastrophic damage may result from rapidly alternating full flight control inputs and that on some airplanes, progressively lighter pedal forces and smaller pedal movements will command the maximum rudder deflection as speed increases. However, the FAA has yet to issue the final rule and respond to the first part of Safety Recommendation A-02-01, which seeks pilot training programs that explain the structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes. In its final report on the American Airlines flight 587 accident, the NTSB also issued Safety Recommendation A-04-59, which asked the FAA to do the following: Develop and disseminate guidance to transport-category pilots that multiple full deflection, alternating flight control inputs should not be necessary to control a transport-category airplane and, thus, should be avoided. In response to this recommendation, on October 25, 2005, the FAA issued Safety Alert for Operators (SAFO) 05002, “Multiple full deflection, alternating flight control inputs.” This SAFO urges directors of safety, directors of operations, fractional ownership program managers, and pilots of transport-category airplanes to (1) familiarize themselves with the location, availability, and content of the “Airplane Upset Recovery Training Aid” and (2) pay particular attention to the cautions against control reversals and pilot-induced oscillations that are repeated throughout the training aid. Following issuance of SAFO 05002, the NTSB classified Safety Recommendation A-04-59 “Closed—Acceptable Action” on June 9, 2006. The NTSB is concerned that, despite Safety Recommendations A-96-120, A-02-01, and A-04-59; FAA SAFO 05002; Airbus FCOM No. 828/1; and the wide distribution of the “Airplane Upset Recovery Training Aid,” pilots may still resort to unnecessary alternating control inputs—including rudder pedal inputs—in an attempt to control their airplanes during a perceived or actual upset, as evidenced by the Air Canada flight 190 accident. The actions taken by the FAA to date, including reviews by POIs, issuance by manufacturers of technical operations bulletins, and distribution of other guidance material, do not appear to have been effective in informing pilots of proper rudder use during upset recovery. Guidance in training aids cautioning against such control inputs and pilot-induced oscillations was not effective in preventing the Air Canada pilots from using alternating rudder inputs in an attempt to control their airplane. The NTSB notes that pilot training regarding rudder system sensitivity and structural certification requirements for the rudder and vertical stabilizer on transport-category airplanes would have provided the accident pilots with additional information about the specific hazard of alternating rudder inputs on these airplanes and the sensitivity of the A320 rudder system at high airspeeds. The actions of the Air Canada flight 190 pilots demonstrate that the need remains for the actions in Safety Recommendation A-02-01. In the 8 years since this recommendation was issued, the FAA has not taken the actions recommended. Therefore, the NTSB reiterates Safety Recommendation A-02-01 and reclassifies it “Open—Unacceptable Response.” Therefore, the National Transportation Safety Board reiterates the following recommendations to the Federal Aviation Administration: Modify 14 Code of Federal Regulations Part 25 to include a certification standard that will ensure safe handling qualities in the yaw axis throughout the flight envelope, including limits for rudder pedal sensitivity. (A-04-56) After the yaw axis certification standard recommended in Safety Recommendation A-04-56 has been established, review the designs of existing airplanes to determine if they meet the standard. For existing airplane designs that do not meet the standard, the FAA should determine if the airplanes would be adequately protected from the adverse effects of a potential aircraft-pilot coupling (APC) after rudder inputs at all airspeeds. If adequate protection does not exist, the FAA should require modifications, as necessary, to provide the airplanes with increased protection from the adverse effects of a potential APC after rudder inputs at high airspeeds. (A-04-57) Review the options for modifying the Airbus A300-600 and the Airbus A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds and, on the basis of this review, require modifications to the A300 600 and A310 to provide increased protection from potentially hazardous rudder pedal inputs at high airspeeds. (A-04-58) In addition, the National Transportation Safety Board reiterates and reclassifies as “Open—Unacceptable Response” the following recommendation to the Federal Aviation Administration: Require the manufacturers and operators of transport-category airplanes to establish and implement pilot training programs that: (1) explain the structural certification requirements for the rudder and vertical stabilizer on transport category airplanes; (2) explain that a full or nearly full rudder deflection in one direction followed by a full or nearly full rudder deflection in the opposite direction, or certain combinations of sideslip angle and opposite rudder deflection can result in potentially dangerous loads on the vertical stabilizer, even at speeds below the design maneuvering speed; and (3) explain that, on some aircraft, as speed increases, the maximum available rudder deflection can be obtained with comparatively light pedal forces and small pedal deflections. The FAA should also require revisions to airplane and pilot operating manuals that reflect and reinforce this information. In addition, the FAA should ensure that this training does not compromise the substance or effectiveness of existing training regarding proper rudder use, such as during engine failure shortly after takeoff or during strong or gusty crosswind takeoffs or landings. (A-02-01) The National Transportation Safety Board issued two safety recommendations and reiterated one safety recommendation (A 04 63) to the European Aviation Safety Agency.
Response: The Safety Board notes that the FAA is evaluating existing certification standards by conducting a study to identify critical rudder control system parameters and human interaction with those controls. The FAA states that, based on the results of the study, it will determine whether the standards need to be updated. Pending the results of the FAA's study and appropriate revisions to Part 25, Safety Recommendation A-04-56 is classified "Open--Acceptable Response." The FAA also indicates that as part of its study, the FAA is developing criteria for assessing the existing fleet of aircraft. Pending completion of the study, application of the criteria to existing airplane designs, and appropriate actions for airplane designs that do not meet the new standards, Safety Recommendation A-04-57 is classified OPEN -- ACCEPTABLE RESPONSE.
Response: Letter Mail Controlled 3/17/2005 12:28:54 PM MC# 2050112 - From Marion C. Blakey, Administrator: The Federal Aviation Administration (FAA) agrees that current standards governing the performance and design of yaw control systems may need to be redefined. To evaluate the existing standards, the FAA is conducting a study to identify critical rudder control system parameters and human interaction with those controls. The FAA will also work with industry to develop a rudder control system standard. Based on the results of the study, the FAA will determine if standards need to be updated. I will keep the Board informed of the FAA's progress on this safety recommendation.