Cessna 560 accident near Farmington, Connecticut, September 2, 2021

The NTSB's narrative final · quoted from the NTSB record

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 pilotincommand (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 secondincommand (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 nearfull 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.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.