Farmington, CT, USA
N560AR
CESSNA 560
The flight crew was conducting a personal flight with two passengers onboard. Before departure, the cockpit voice recorder (CVR) captured the pilots verbalizing items from the before takeoff checklist, but there was no challenge response for the taxi, before takeoff, or takeoff checklists. Further, no crew briefing was performed and neither pilot mentioned releasing the parking brake. The left seat pilot, who was the pilot flying (PF) and pilot in command (PIC), initiated takeoff from the slightly upsloping 3,665-ft-long asphalt runway. According to takeoff performance data that day and takeoff performance models, the airplane had adequate performance capability to take off from that runway. Flight data recorder (FDR) data indicated each thrust lever angle was set and remained at 65° while the engines were set and remained at 91% N1. During the takeoff roll, the CVR recorded the copilot, who was the pilot monitoring (PM) and second in command (SIC), making callouts for “airspeed’s alive,” “eighty knots cross check,” “v one,” and “rotate.” A comparison of FDR data from the accident flight with the previous two takeoffs showed that the airplane did not become airborne at the usual location along the runway, and the longitudinal acceleration was about 33% less. At the time of the rotate callout, the airspeed was about 104 knots calibrated airspeed, and the elevator was about +9° airplane nose up (ANU). Three seconds after the rotate callout, the CVR recorded the sound of physical straining, suggesting the pilot was likely attempting to rotate the airplane by pulling the control yoke. The CVR also captured statements from both the copilot and pilot expressing surprise that the airplane was not rotating as they expected. CVR and FDR data indicated that between the time of the rotate callout and the airplane reaching the end of the airport terrain, the airspeed increased to about 120 knots, the weight-on-wheels (WOW) remained in an on-ground state, and the elevator position increased to a maximum value of about +16° ANU. However, the airplane’s pitch attitude minimally changed. After the airplane cleared the end of the airport terrain where the ground elevation decreased 20 to 25 ft, FDR data indicate that the WOW transitioned to air mode with near full ANU elevator control input, and the airplane pitched up nearly 22° in less than 2 seconds. FDR data depicted forward elevator control input in response to the rapid pitch-up, and the CVR recorded a stall warning then stick shaker activation. An off airport witness reported seeing the front portion of the right engine impact a nearby pole past the departure end of the runway. The airplane then rolled right to an inverted attitude, impacted the ground, then impacted an off-airport occupied building. There was no evidence of preimpact failure or malfunction of the flight controls or engines before impact with the pole. Postaccident examination and computed tomography of the parking brake valve revealed the parking brake was in the ON (or closed) position at the time of the accident. There was no evidence of preimpact failure or malfunction of the brakes, parking brake knob, cable, or parking brake valve. The closed position of the parking brake valve would have continued to apply pressure to both main landing gear wheel brakes during the takeoff roll, and resulted in the continuous rubber transfer from both main landing gear tires on the runway that was observed from the starting point of each to the departure end of the runway. Additionally, the smoke that witnesses observed and the surveillance video captured trailing the airplane as it traveled down the runway was likely the result of the brakes still being applied. An NTSB performance study found that the retarding force at the wheel/runway interface that would have resulted from application of the wheel brakes during the takeoff roll created an airplane-nose-down (AND) pitching moment that opposed airplane-nose-up (ANU) rotation. When the airplane reached Vr, the pitching moment opposing the ANU rotation likely overpowered the elevator’s ability to rotate the airplane nose up and prevented the airplane from taking off. When the retarding force at the wheel/runway interface was no longer present after the airplane reached the end of the airport terrain, the airplane responded aerodynamically to the near-full aft control yoke/column input and began pitching up rapidly. Although the airplane flight manual takeoff checklist included an item for “brake release,” it did not specifically indicate “parking brake release.” While a specific and unambiguous checklist item that directed flight crews to verify that the parking brake had been released prior to takeoff might generally provide a mechanism for flight crews to consistently perform this pre-takeoff task, it is unlikely that a specific mention to release the parking brake in the takeoff checklist would have mitigated this accident because there were no challenge responses to checklists during the flight. The ON position of the parking brake knob and its associated valve could not be observed by the copilot (due to its obscured location on the lower left side of the left seat pilot), therefore only by completing a challenge response as part of a specified checklist could the copilot have any knowledge of the position of the parking brake. Further, the status of the parking brake was not indicated or annunciated in the cockpit and was not part of the NO TAKEOFF configuration warning system. The accident airplane was manufactured as an XLS+ derivative model of the Cessna 560XL, which was certified to a parking brake standard that was first issued in 1965. Cessna Aircraft Company (now Textron Aviation, Inc.), the airplane manufacturer, applied to the Federal Aviation Administration (FAA) for certification of the XLS+ as a derivative airplane in February 2006, nearly 4 years after a change to the parking brake regulation that required indication in the cockpit when the parking brake was not fully released. Because there were no substantial changes to the parking brake system of the XLS+ from the original type design, the FAA process for certification of a derivative aircraft allowed the parking brake system to be certified to the original 1965 standard without a parking brake indication. It is likely that a cockpit indication when the parking brake was not fully released would have alerted both the pilot and copilot of the parking brake’s status so that they could have immediately aborted the takeoff attempt and prevented the accident. To address this safety issue, which was also identified in NTSB case number WPR19FA230, the NTSB issued recommendations to the FAA on May 4, 2022, to require that in-service (A-22-8) and newly manufactured Cessna 560XL airplanes and future derivative models (A-22-9) meet the in-cockpit parking brake indication requirements of the updated certification standard. Based on a similar accident in 2015 involving a Cessna 550 and a serious incident in 2018 involving a Cessna 560XLS+, the Australian Transport Safety Bureau (ATSB) and Nigerian Accident Investigation Bureau (AIB), respectively, also recommended that the manufacturer include a parking brake indication. In addition, the FAA’s certification process for derivative aircraft or changed aeronautical product did not consider or require compliance with regulation changes to systems like the Cessna 560XL parking brake indication because it determined that there were no significant changes to the parking brake system. Although the FAA accurately followed the certification process for derivative aircraft, identifying and requiring the safety benefit of a parking brake indication during that process could have prevented this accident and at least one other serious incident. Therefore, the certification process for the Cessna 560XL, as a derivative aircraft, likely contributed to this accident by not evaluating the impact that the updated certification standards would have and did not identify the safety enhancing value that requiring a parking brake indication would provide.
HISTORY OF FLIGHTOn September 2, 2021, at 0951 eastern daylight time, a Cessna 560XLS+ airplane, N560AR, was destroyed when it was involved in an accident near Farmington, Connecticut. All four airplane occupants (the pilot, copilot, and two passengers) were fatally injured. One person on the ground sustained serious injuries, and three people sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. According to FAA air traffic control audio recordings and CVR transcription, about 0913, the copilot contacted the Yankee Terminal Radar Approach Control Facility to obtain an instrument flight rules clearance to Dare County Regional Airport (MQI), Manteo, North Carolina. The controller provided the clearance and advised the flight to hold for release. About 0948, the copilot contacted the controller and advised that the flight was taxiing and would be ready in 1 minute, and the controller instructed the flight crew to hold for release. The flight taxied toward runway 2, and at 0948:20, the CVR recorded the controller advising the flight crew that the flight was released for departure and to enter controlled airspace on a 20° heading. The copilot, who was the PM and seated in the right seat as SIC, repeated the instruction. The CVR recorded the PM discussing the departure frequency and transponder code while the PF, who was seated in the left seat and was PIC, said, “kay flaps. trim three times. pitot heat on.” The copilot then said that the pitot static was coming on. Those items were part of the before takeoff checklist, but there was no challenge response for the taxi, before takeoff, or takeoff checklists, and the flight crew did not perform a crew briefing. Further, there was no mention in the CVR recording of releasing the parking brake before takeoff was initiated. FDR data did not indicate any flight control movements consistent with a check of the flight controls. The CVR recorded the copilot make a radio call on the airport common traffic advisory frequency advising that the flight would be departing runway 2 straight out and that the final and base legs of the airport traffic pattern appeared clear. The sound of engine power advancing was heard at 0950:15. According to data from the airplane’s FDR, both thrust levers were set at about 65°, and both engines were set at and remained at 91% N1 throughout the takeoff roll. While accelerating on the runway the CVR recorded the copilot stating that “power is set…airspeed’s alive… eighty knots cross check… v one”, with the v one call occurring about 1,670 ft down the 3,665-ft-long runway. The flight continued on the runway and at 0950:44, the copilot called, “Rotate.” According to the data from the FDR, the airplane was about 2,000 ft down the runway at about 104 knots calibrated airspeed and the elevator was about +9° when the copilot made the rotate callout. Three seconds later, the CVR recorded the copilot stating, “Oht oht ‘sa matter,” followed 1.7 seconds later by a sound of heavy strain from the pilot and him stating, “it’s [not] rotating.” Then 2.4 seconds later, a sound of physical strain/grunt was recorded from the pilot. The airplane continued along the runway centerline with left rudder input between 2° and 4,° which decreased to about 0.3° when the airplane was about 2,375 ft down the runway. The flight crew applied an increasing amount of right rudder input to a maximum of about 10°, while the right rudder input remained until the flight was about 2,500 ft down the runway, and a slight deviation to the right began. Several on- and off-airport video cameras that captured the takeoff roll and final portion of the flight showed smoke trailing the airplane, and a ground track reconstruction model determined the smoke appeared about 2,685 ft down the runway (the model is further discussed in the Additional Information section of this report). While deviating to the right, the flight crew applied left rudder input to a maximum of about 18°, and the deviation to the right ended about 0950:52 when the airplane was about 3,125 ft down the runway. The rudder values remained near neutral from the point when the right deviation stopped and the airplane track remained straight to the end of the runway, though the airplane path was offset right of the runway centerline. When the airplane reached the end of the airport terrain, FDR data indicated the airspeed had increased to about 120 knots, the elevator deflection increased to a maximum value of about +16°, the WOW remained in an on-ground state, and the pitch of the airplane minimally changed briefly to +1° then decreased to 0°. The FDR data further indicated that past the end of the airport terrain where the ground elevation decreased 20 to 25 ft, the WOW indication changed from on-ground to air mode, the elevator position increased to a maximum recorded value of about +17° deflection (or ANU), and the airplane’s pitch increased to about +22° in less than 2 seconds. While the airplane rapidly pitched up, the elevator position rapidly decreased to about 1.0°. At 0950:54, the CVR recorded the sound of electronic stall warning followed one-tenth of a second later by stick shaker activation. Two witnesses on the ground reported seeing a puff of blue smoke behind the airplane during the takeoff roll. One witness noted the airplane appeared to be “going slower” compared to previous flights, and because of that, he knew there was a problem. That same witness also reported that the airplane never lifted off from the runway. A witness who was located about 280 ft north-northeast of the departure end of the runway reported seeing the airplane come off the runway in a level attitude. As the airplane continued, it pitched into a nose-up attitude but was not climbing. He noted the front portion of the right engine impact a nearby pole followed by a shower of sparks and a metallic grinding sound. FDR data showed that the N1 and N2 values of the No. 2 engine were 91.0% and 99.4%, respectively before the airplane impacted the pole past the departure end of the runway. After impacting the pole, the right engine N1 and N2 values immediately decreased to 80.1% and 95.1%, respectively, then both continued to decrease despite the thrust lever angle for both engines remaining at 65° for the remainder of the recording. The airplane began a roll to the right and became inverted in about 3.5 seconds. The airplane impacted the ground then an occupied building, whose sprinkler system was activated. The building and its contents sustained significant structural and fire damage. PERSONNEL INFORMATIONPilot The pilot was a salaried pilot employed by Interstate Aviation, Inc., which was the accident operator. He received transition training in a level D simulator for the Cessna 560XL (Excel), which was the original type design of the accident airplane, at Flight Safety International (FSI) in December 2009. He subsequently obtained recurrent training at FSI in the Excel in 2017, and recurrent training in the XLS+ (a derivative model of the Cessna 560XL) in 2018, 2019, 2020, and 2021. All training was conducted in a level D simulator, and he passed all of the practical tests on the first attempt. On the paperwork for his latest training, Citation XLS+ Recurrent Pilot-In-Command Course, the instructor remarked during one flight that he observed no weaknesses, and his strengths were, “Good aircraft control, CRM [crew resource management], and procedures.” The accident operator’s president, who normally flew as copilot with the accident pilot, reported that during typical takeoffs, the accident pilot would center the airplane on the runway, then when almost to a full stop, he would begin the takeoff. The accident pilot would not normally stop on the runway, apply the brakes, then advance thrust and release the brakes. When they flew together, they used the checklist and performed challenge and response. During takeoff, they would call airspeed alive, 80 knots crosscheck, takeoff-decision speed (V1), rotate. At V1, the flight crew’s hands would move from the thrust levers to the control yoke, then engage the autopilot at 400 ft. Copilot The copilot was a contract pilot for the accident operator. A review of his available training records revealed that he completed initial training at FSI in a Cessna 525 (Citation Jet) in November 2015. He also received training in the Gulfstream G450 in 2018 and recurrent training at FSI in the Gulfstream G550 on two occasions in 2019. The latest training performed in a level D simulator between November 18, 2019, and November 23, 2019, consisted of 6 hours as the PF and 6 hours as the PM. A review of provided logbook entries revealed no entries showing a sign off as SIC specifically for the accident make and model airplane. Entries between September 2020 and July 29, 2021, showed that he logged 11 flights as SIC in the accident airplane totaling 25 hours. The remarks section for the flights in the accident airplane did not indicate whether he had performed engine-out procedures, maneuvering with an engine out while acting as pilot-in-command, and CRM training. The attorney representing the copilot’s estate cited the flights in the accident airplane but reported the copilot’s family was unable to locate any records concerning simulator training and had no recollection of whether he had attended training for the Cessna 560 series. AIRCRAFT INFORMATIONAccording to the airplane’s type certificate data sheet and FAA-approved airplane flight manual, the minimum flight crew for all operations were one pilot and one copilot. Inspections of the airplane and its systems as part of the manufacturer’s scheduled inspection program were last performed last on July 2, 2021. At the beginning of the accident flight, the airplane had accumulated 11.3 hours since the last inspections were completed. According to the aircraft status report, the airplane’s parking brake valve, which is considered an on-condition item, was original to the airplane when it was manufactured in 2009. A pilot who had flown the airplane on August 10, 2021, and again on August 13, 2021, reported there were “zero squawks” on either flight. The parking brake knob was located on the tilt panel forward of the left seat pilot’s seat adjacent to the occupant’s knee and was not visible to the right seat occupant. Per the airplane operating manual, the parking brake is set by depressing the toe brakes in the normal manner, then pulling out the parking brake pull knob on the left lower side of the tilt panel. That action mechanically actuates the parking brake valve, trapping fluid in the brakes. The parking brake is released by pushing in the parking brake pull knob. Figure 1. Pictures from an exemplar 560 XLS+ showing the parking brake off (left) and set (right). The airplane was equipped with a crew alerting system (CAS) that did not incorporate parking brake valve position as part of its activation logic, nor was there an indication or annunciation in the cockpit when the parking brake was not fully released. A red NO TAKEOFF warning CAS message would display a NO TAKEOFF aural warning for some conditions that would impede a safe takeoff, such as if the throttles were advanced beyond the climb setting or the flaps were not configured for takeoff. Certification The parking brake standard outlined in 14 CFR 25.735, Brakes and Braking Systems, was first issued in 1965 and remained the standard until May 2002. To meet the original requirements of 14 CFR 25.735 in force between 1965 and 2002, the parking brake must prevent the airplane from rolling on a paved, level runway when set by the pilot and with takeoff power on the critical engine. In May 2002, the regulation was changed to Amendment 25-107, which incorporated, in part, indication in the cockpit when the parking brake was not fully released. The FAA’s aircraft certification process in 14 CFR 21.101, Certification Procedures for Products and Parts - Changes to Type Certificates, allowed an aircraft manufacturer to introduce a derivative model (or “changed aeronautical product”) as a design update on a previously certificated aircraft and to add the changed product to an existing type certificate. The FAA approved changes for derivative models if it found that (1) if the change was not significant, (2) for those areas or components not affected by the change, (3) if such compliance would not contribute materially to the level of safety, and (4) if such compliance would be impractical. That process enabled a manufacturer to introduce design updates without resubmitting the entire aircraft design for certification review. When the accident aircraft manufacturer applied to the FAA for certification of the XLS+ on February 17, 2006, 14 CFR 21.101 Amendment 21-77 was effective and stated that an applicant must show that the changed product complies with the airworthiness regulations in effect on the date of the application. However, the applicant may show compliance with an earlier amendment of a regulation for a change the FAA finds not to be significant. Although the location and movement of the parking brake knob in the cockpit for the XLS+ changed from the previous design, there was no change to the parking brake architecture or operation. Because there were no significant changes to the parking brake system, the FAA did not require recertification of the parking brake system on the XLS+. Thus, the XLS+ was certificated on May 30, 2008, to the 1965 parking brake standard. AIRPORT INFORMATIONAccording to the airplane’s type certificate data sheet and FAA-approved airplane flight manual, the minimum flight crew for all operations were one pilot and one copilot. Inspections of the airplane and its systems as part of the manufacturer’s scheduled inspection program were last performed last on July 2, 2021. At the beginning of the accident flight, the airplane had accumulated 11.3 hours since the last inspections were completed. According to the aircraft status report, the airplane’s parking brake valve, which is considered an on-condition item, was original to the airplane when it was manufactured in 2009. A pilot who had flown the airplane on August 10, 2021, and again on August 13, 2021, reported there were “zero squawks” on either flight. The parking brake knob was located on the tilt panel forward of the left seat pilot’s seat adjacent to the occupant’s knee and was not visible to the right seat occupant. Per the airplane operating manual, the parking brake is set by depressing the toe brakes in the normal manner, then pulling out the parking brake pull knob on the left lower side of the tilt panel. That action mechanically actuates the parking brake valve, trapping fluid in the brakes. The parking brake is released by pushing in the parking brake pull knob. Figure 1. Pictures from an exemplar 560 XLS+ showing the parking brake off (left) and set (right). The airplane was equipped with a crew alerting system (CAS) that did not incorporate parking brake valve position as part of its activation logic, nor was there an indication or annunciation in the cockpit when the parking brake was not fully released. A red NO TAKEOFF warning CAS message would display a NO TAKEOFF aural warning for some conditions that would impede a safe takeoff, such as if the throttles were advanced beyond the climb setting or the flaps were not configured for takeoff. Certification The parking brake standard outlined in 14 CFR 25.735, Brakes and Braking Systems, was first issued in 1965 and remained the standard until May 2002. To meet the original requirements of 14 CFR 25.735 in force between 1965 and 2002, the parking brake must prevent the airplane from rolling on a paved, level runway when set by the pilot and with takeoff power on the critical engine. In May 2002, the regulation was changed to Amendment 25-107, which incorporated, in part, indication in the cockpit when the parking brake was not fully released. The FAA’s aircraft certification process in 14 CFR 21.101, Certification Procedures for Products and Part
The pilot-in-command’s failure to release the parking brake before attempting to initiate the takeoff, which produced an unexpected retarding force and airplane-nose-down pitching moment that prevented the airplane from becoming airborne within the takeoff distance available and not before the end of the airport terrain. Contributing to the accident were the airplane’s lack of a warning that the parking brake was not fully released and the Federal Aviation Administration’s process for certification of a derivative aircraft that did not identify the need for such an indication.
Source: NTSB Aviation Accident Database
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