Safety By Design Flight Certification AE 6362 Airbus Derivative Team Project Dr. Daniel P. Schrage Course Instructor
Safety By Design Flight Certification AE 6362 Presentation Outline Description of the Crash of American Airlines 587, an Airbus A Description of Resulting Certification Issues Description of the key disciplines and their interactions that were involved with the accident Some Key References Project Approach
Safety By Design Flight Certification AE 6362 Description of the Crash of American Airlines Flight 587, an Airbus A On Nov. 12, 2001, at about 9:17 a.m. American Airlines Flight 587, an Airbus A , N14053, crashed in Belle Harbor, NY, several minutes from Kennedy International Airport. The plane was on a scheduled flight to Santo Domingo, Dominican Republic. All 251 passengers and nine crewmembers aboard the plane died, as did 5 on the ground (making it the second worst aviation disaster in U.S. history) While the Composite Vertical Tail snapped off during a series of full, opposite rudder deflections, the cause of the large rudder deflections resulted from a number of extenuating circumstances: –Two wake encounters from a JAL 747 aircraft which took off approximately 1 minute and 45 seconds before Flight 587 –The pilot applied pedal inputs at a high speed flight condition (~250kts), where pedal inputs are usually not used –A rudder system design which produces identical percentages of deflection with different inputs (different from the Boeing wide-bodies). On an A , full available rudder travel of 9.3 degrees at 250 knots requires about 32 lbs of force on the pedal (the breakout force is 22 lbs) required, NTSB said. But full travel available on the ground, which is 30 degrees because it’s not restricted by a rudder limiter, requires 65 lbs of force
Safety By Design Flight Certification AE 6362 Description of Resulting Certification Issues Analysis showed that Flight 587’s tail experienced forces well beyond “ultimate load” – the limit of an airframe’s bend-but-don’t- break range that, even under the most extreme circumstances, is rarely approached The National Transportation Safety Board (NTSB) investigators on the accident question how can the aviation system be improved to prevent similar occurrences and are looking closely at whether certifications are adequate The NTSB said it is “noteworthy” that certification rules don’t require manufacturers to prove their designs can withstand certain, extreme combinations of rudder movements, such as the ones that the AA 587 jet experienced just before its tail snapped off NTSB also expressed concern about variances in rudder system design Airline pilots are perturbed by NTSB recommendations which state flight crews must be made aware that aggressive rudder input can induce structural damage or failure but do not define ways to recognize or prevent disaster – Pilots want clear-cut definitions, and quickly
Safety By Design Flight Certification AE 6362 Description of the key disciplines and their interactions that were involved with the accident Aerodynamics – to understand the air wakes and air loads on the vertical tail Structures – to understand the structural loads and structural integrity of the vertical tail Flight Mechanics & Controls – to understand the flight path encountered and the flight control functions applied, both manually and automatically Human Factors – to understand the pilot actions in responding before and after the air wake encounters System Safety and Reliability – to understand and be able to model the complex interactions between hardware, software and live-ware (human interaction)
Safety By Design Flight Certification AE 6362 Some Key References Numerous Aviation Week articles: NTSB-American Airlines Flight 587: NTSB Safety Recommendation, Feb. 8, 2002 NTSB Human Performance Report, Aug. 16, 2002 NTSB Systems Group Chairman’s Factual Report of Investigation, Oct 9, 2002, Docket No. SA-522 A310/A FCOM Bulletin, March 2002, Subject No. 40: Use of Rudder on Transport Category Airplanes Raymond, E.T., Aircraft Flight Control Actuation System Design, SAE, 1993 NRC Study: Aviation Safety and Pilot Control: Understanding and Preventing Unfavorable Pilot-Vehicle Interactions, National Academy Press, Washington, D.C
Safety By Design Flight Certification AE 6362 Project Approach Follow the approach outlined in the AE6362 Team Project, including meeting all deliverables Concentrate on modeling and evaluating the rudder and its control system, to include hardware, software, and human design assessment Identify deficiencies and shortcomings in the current FAR 25 Certification requirements Recommend a derivative change to the A to insure better system safety and reliability Develop a supplemental type certicate (STC) plan for incorporating the changes to the A Derivative
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362
Safety By Design Flight Certification AE 6362