CESSNA 560

Full Narrative

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 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. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site area revealed a broken telephone/electrical pole about 011° and 361 ft past the departure end of the runway, about 27 ft above ground level and about 1.8 ft lower than the departure end of the runway. An approximate 3ftlong section of the outboard end of the airplane’s right inboard flap was located in wetlands east of the impacted pole. Additional airplane wreckage was located close to the impacted pole.

Examination of the area north of the impacted pole revealed ground scars on grass about 850 ft from the damaged pole on a magnetic heading of 036° about 245 ft from the impacted building. The aft empennage came to rest inverted on a magnetic heading of 130° outside of the building, while the heatdamaged cockpit and cabin were just inside the impacted building. The wing, which exhibited extensive impact and fire damage, was both inside and immediately outside the building.

Wreckage including upper cabin material, were found along the ground impact energy path consistent with the airplane being inverted at impact. Flight control surfaces, and engine components were also noted along the energy path between the ground scar and the resting position of the airplane.

Examination of the wreckage revealed the wings, cockpit, and cabin were damaged and/or consumed by a post-crash fire. All primary and secondary flight control surfaces or the remains of them, both wingtips, the top of the vertical stabilizer and rudder, ends of both horizontal stabilizers and elevators were accounted for at the accident site.

Examination of the flight controls for roll, pitch, and yaw revealed no evidence of preimpact failure or malfunction. Both speed brakes were retracted. Although the positions of the flaps based on the flap actuators could not be determined, the FDR data reflected they were set to and remained at 15° throughout the recorded data. The two-position horizontal stabilizer was positioned to takeoff/land, and according to FDR data, it remained at that position throughout the recorded data. According to the FDR data during takeoff, the aileron trim was between 10° and 11° tab trailing edge down or left wing down, while the elevator trim was 18.02° ANU, which was beyond the maximum limit and did not change throughout the recorded data. The rudder trim actuator measured 1.9 inches, which equated to neutral. The elevator and aileron trim values recorded by the FDR during the accident flight were consistent with the same values for the entirety of data for each recorded by the FDR.

Examination of the parking brake handle revealed it remained partially attached to the tilt panel. The handle was extended about 2.5 inches and its sleeve was bent and fractured. Examination of the parking brake push/pull rod and knob with section of panel mount, deformed and fractured sleeve, and sections of control cable revealed that the fractured or cut surfaces of the sleeve, Bowden cable, and inner actuated cable were consistent, respectively, with overstress fractures or being cut in the field for recovery.

The field examination of both engines revealed no anomalies on either engine that would have precluded normal operation. FDR data further showed there were no fault codes for either engine recorded on its respective data collection unit, and both engines were operating normally until just past the impact with the pole.

Parking Brake Valve, Landing Gear, and Brake System Components

Examination of the parking brake valve revealed it was separated from the structure and thermally damaged. The cable remained attached to the lever, which was bent aft and positioned against the parking brake full-on stop toward the single structural attach bolt.

X-ray radiograph and computed tomography scanning of the parking brake valve revealed that the shaft flat was adjacent to the mechanisms (consistent with the valve being in the closed or brake set position), and the levertoshaft interface did not show any indications of cracks, missing material, or other abnormalities. Further, there were indications of high-density particles and possible debris consistent with burned material from outside the valve or from heated material within the valve. Comparison between the accident valve and an exemplar valve revealed that the accident valve was in a closed position when exposed to elevated temperatures, which was confirmed when disassembled. The parking brake valve position and normal wheel or parking brake application were not recorded by the FDR. Other than its closed position during operation, examination of the parking brake valve did not reveal any anomalies that would have precluded normal operation.

Examination of the left and right main landing gear revealed postimpact thermal damage and no anomalies that would have precluded normal operation.

Examination of the left brake revealed it could not be pressurized. The wear pin right of shuttle valve was bent and could not be measured, and without hydraulic pressure applied to the brake stack, the other wear pin left of shuttle valve was measured at 0.941 inch. The pistons appeared to be fully retracted. Disassembly of the brake stack revealed normal wear of the pressure plate, and the stators and rotors exhibited normal wear. No anomalies were noted with the left brake that would have precluded normal operation.

Examination of the right brake revealed it could not be pressurized. Without hydraulic pressure applied to the brake stack, one wear pin (right of shuttle valve) extension was 0.285 inch and the other wear pin (left of shuttle valve) extension was 0.300 inch. Disassembly of the brake stack revealed normal wear of the pressure plate, and the stators and rotors exhibited normal wear. No anomalies were noted with the right brake that would have precluded normal operation. ADDITIONAL INFORMATIONPerformance Study
An NTSB performance study with representatives of the airplane manufacturer and the FAA used data from the FDR, CVR, video footage, tire skid marks on the runway, witness information, environmental conditions, engine performance, weight and balance calculations, aerodynamics and engine data generated during flight test, and airplane flight manual data. The study found that for the accident flight conditions that day at 15° flap setting, the calculated values in terms of knots calibrated airspeed (KCAS) for target V1, rotational speed (Vr), and angle-of-climb speed (V2) speeds were 106, 111, and 120, respectively.

During the four preceding takeoffs, the calculated airplane braking coefficient values (the friction between the tires and the runway) during the takeoff ground roll were between about 0.02 to 0.03. During the accident takeoff ground roll, the calculated airplane braking coefficient values ranged from about 0.09 to 0.11 for groundspeeds below 100 knots and from 0.11 to 0.35 between 100 and 118 knots. Peak longitudinal acceleration was about 0.27 g during the accident flight and about 0.4 g during the previous 2 takeoffs. In both previous takeoffs, the elevator began deflecting at similar speeds to the accident takeoff attempt and the airplane rotated to about 10° over about 4 seconds, lifting off from the runway in both cases as it rotated. The FDR data showed that the recorded aileron and elevator trim readings during the accident flight takeoff were consistent with the previous four takeoff settings.

During the accident flight takeoff roll, FDR data showed that the crew began ANU elevator deflection near V1 and reached full ANU elevator deflection at Vr. The airplane accelerated while on the runway to an airspeed above 115 knots, but the airplane pitch attitude did not increase above 1° before the airplane’s departure from the improved pavement surface.

The study indicated that the Vr value correlated to about 105 knots ground speed. Using the vertical center of gravity value of 5.4 ft, at the Vr groundspeed, the calculated equivalent AND pitching moment due to adverse retarding force was about 12,420 ft pounds which was 77% greater than the nominal elevator/horizontal tail ANU pitching moment capability which was at least 7,000 ft pounds. Between 105 and 110 knots groundspeed, the equivalent AND pitching moment decreased to about 9,180 ft pounds but was still about 31% greater than the nominal elevator/horizontal tail ANU pitching moment capability. Beginning at 110 knots groundspeed, the equivalent AND pitching moment due to the adverse retarding force significantly increased from about 9,180 ft pounds and reached an equivalent AND pitching moment of 32,940 ft pounds at 118 knots.

For speeds at and beyond Vr, a successful takeoff with such an unexpected, adverse retarding force at the wheel/runway interface would have required an ANU pitching moment capability that exceeded the accident airplane’s certified envelope, as measured by the forward center of gravity limit of the weight and balance envelope.

Takeoff Checklists

A review of the FAA-approved airplane flight manual revealed that its checklists for preliminary cockpit inspection, before starting engines, and shutdown each include setting the parking brake. The static takeoff and rolling takeoff checklists both cite “Brakes…Release” with no specific mention of the wheel brakes or parking brake.

Airplane Location Correlated with Smoke

To determine the airplane’s location when smoke appeared, NTSB created a ground track reconstruction model overlaid onto aerial imagery, which included video surveillance frames, longitudinal acceleration from FDR data, and the measured runway tire marks. According to the model, the video frame time 0952:33 aligned with FDR time 5048.8. After this video frame time, the FDR showed a decrease in the longitudinal acceleration data – a decrease of 0.10/0.15 g to 0.1 g and lower. According to the time alignment with the model, the white smoke on the video aligned with where the runway marks associated with the right main landing gear darkened, 2,685 ft past the approach end of runway 2.

Previous Related Recommendations and Similar Accidents

During its investigation of this accident and another Cessna 560XL accident (NTSB case number WPR19FA230), the NTSB determined that without a parking brake indication, some Cessna 560XL pilots may not recognize that the parking brake is not fully released and attempt to take off, which could result in a runway overrun. Because Cessna 560XL airplanes continue to operate in the United States without a parking brake indication and the manufacturer continues to manufacture and deliver airplanes in the United States without such an alert, the NTSB issued the following safety recommendations:
Safety Recommendation A-22-8 to the FAA: Issue an airworthiness directive for in-service Cessna 560XL airplanes to require that they meet the parking brake indication requirements of Amendment 25-107 of 14 CFR 25.735.
Safety Recommendation A-22-9 to the FAA: Revise the type certification basis for Cessna 560XL airplanes and future derivative models to require that newly manufactured airplanes meet the parking brake indication requirements of Amendment 25-107 of 14 CFR 25.735. (NTSB Aviation Investigation Report NTSB/AIR-22-06, “Require Safeguards to Prevent Cessna 560XL Takeoff with Parking Brake Engaged.”)
In September 2015, the Australian Transport Safety Bureau (ATSB) investigated a similar accident near Lismore, New South Wales, Australia, involving a Cessna 550 that did not have cockpit annunciation to alert the pilots that the parking brake was set. The pilot did not release the parking brake before attempting to takeoff, which led to a rejected takeoff and runway overrun. The ATSB made recommendations for all Cessna Citation airplanes (including the Cessna 560XL) to include a parking brake annunciation. In an October 2017 response, the manufacturer stated that the recommended actions were not needed because it was “simple airmanship” to remember to release the parking brake before the takeoff run. (ATSB Transport Safety Report AO-2015-114, “Runway excursion involving Cessna 550, VH-FGK, Lismore Airport, New South Wales, 25 December 2015.”)
On October 3, 2018, a Cessna 560XL, 5N-HAR, was involved in a serious incident in Bauchi State, Nigeria. The XLS+ derivative model airplane, which was not equipped with parking brake annunciation, would not rotate during takeoff at Vr and the takeoff was aborted, which resulted in a wheel fire and no injuries. The Nigerian Accident Investigation Bureau (AIB) recommended the airplane manufacturer redesign the parking brake system to incorporate takeoff protection visual and aural warnings, and to make the position of the parking brake control visible to both flight crew members. The manufacturer stated that, as of the publication of this report, it was reviewing the recommendations but had not yet responded to AIB. (AIB Aircraft Accident Report NPF/2018/10/03/F, “Final Report on serious incident involving Cessna Citation 560 XLS+ aircraft with nationality and registration marks 5N-HAR operated by the Nigeria Police Airwing which occurred at Sir Abubakar Tafawa Balewa Airport Bauchi, Nigeria on 3rd October, 2018.”) FLIGHT RECORDERSThe airplane was equipped with a CVR and FDR.

The CVR did not show obvious signs of deformation damage but did show some evidence of heat damage. The recorder’s crash survivable memory unit and the internal non-volatile memory chip stack appeared undamaged. The chip stack and associated ribbon cable were in good condition and were read out normally using an L3 FA-2100 surrogate. The data downloaded normally from the CVR and produced files consistent with the logic of a 2-hour CVR. The audio quality for all channels was characterized as “good.”

The FDR was covered with dirt and carbon soot and combustion particles. The memory module ribbon cable, and connector showed no signs of heat stress. The temperature dot indicated the memory module was not compromised by heat exposure. The memory module was downloaded and contained approximately 197 hours of data. The event flight was the last flight of the recording, and its duration was approximately 6 minutes. MEDICAL AND PATHOLOGICAL INFORMATIONPostmortem examinations of the flight crew were performed by the Office of the Chief Medical Examiner, Farmington, Connecticut. The cause of death for the pilot was blunt injuries of head, torso, and extremities, and the cause of death for the copilot was blunt injuries of head, neck, torso, and extremities. The autopsy report for the copilot also cited moderate coronary artery atherosclerosis.

Toxicology testing performed by the FAA Forensic Sciences Laboratory on the pilot’s specimens detected 51 mg/dL glucose, along with unquantified amounts of atenolol (which is used to treat high blood pressure), acetaminophen (sometimes marketed as Tylenol), and salicylic acid (Aspirin), which are not generally considered impairing.

Toxicology testing performed by the FAA’s Forensic Sciences Laboratory on the copilot’s urine and vitreus detected 14 mg/dL and 48 mg/dL glucose, respectively, along with unquantified amounts of amlodipine, which the copilot had reported using to treat high blood pressure; these are not generally considered impairing. Toxicology testing also detected desmethylsildenafil (Viagra), which is not generally considered impairing, but the FAA states that pilots should wait 8 hours before flying to monitor for side effects such as symptomatic low blood pressure.