Tuesday, September 28, 2021

Cessna 560 Citation XLS+, N560AR: Fatal accident occurred September 02, 2021 near Robertson Field Airport (4B8), Plainville, Hartford County, Connecticut

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

The National Transportation Safety Board traveled to the scene of this accident.
 
Additional Participating Entities: 
Federal Aviation Administration / Flight Standards District Office; Bradley, Connecticut
Textron Aviation; Wichita, Kansas

Brook Haven Properties LLC


Location: Farmington, CT 
Accident Number: ERA21FA346
Date & Time: September 2, 2021, 09:51 Local
Registration: N560AR
Aircraft: Cessna 560
Injuries: 4 Fatal, 1 Serious, 3 Minor
Flight Conducted Under: Part 91: General aviation - Personal

On September 2, 2021, at 0951 eastern daylight time, a Cessna 560XL airplane, N560AR, was destroyed when it was involved in an accident near Farmington, Connecticut. The two pilots 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 Part 91 personal flight.

The flight crew had filed an instrument flight rules (IFR) flight plan from Robertson Field Airport (4B8), Plainville, Connecticut to Dare County Regional Airport (MQI), Manteo, North Carolina. After obtaining their IFR clearance from air traffic control, the flight crew taxied the airplane onto runway 2 for departure.

Two witnesses observed the takeoff roll with one reporting the airplane was “going slower” than they had seen during previous takeoffs. When the airplane was about 2/3 down the runway, one witness noted a puff of blue colored smoke from the back side of the airplane. The other witness stated that the nose landing gear was still on the ground as the airplane passed a taxiway intersection near the mid-point of the runway and he said to a friend with him that something was wrong.

A third witness, who was beyond the departure end of the runway, noted the airplane departed the runway in a level attitude. After clearing the runway, the airplane’s nose pitched up, but the airplane was not climbing. The airplane then impacted a powerline pole, which caused a small explosion near the right engine followed by a shower of softball-size sparks. After hitting the pole, the noise of the engine went from normal sounding to a much more grinding, metallic sound. The airplane then began to oscillate about its pitch and roll axis before the witness lost sight of it behind trees.

Postaccident examination of the 3,665-ft-long runway revealed tire skid marks from the right main landing gear tire that were right of the runway centerline beginning about 2,360 ft from the approach end of the runway. The mark from the right tire continued, while a mark from the left main landing gear tire was noted left of runway centerline beginning about 2,480 ft from the approach end of the runway. The marks from both main landing gear tires continued and veered slightly to the right but were continuous from where first observed to the end of the runway and onto a short width of grass immediately adjacent to the departure end of the runway. The grassy terrain beyond the departure end of the runway then sloped steeply downward toward a road, and the elevation change between the runway area and the road was about 20 ft.

An approximate 3-ft-long section of airplane’s right inboard flap was found near the damaged power pole, which was located about 361 ft beyond the departure end of the runway. A ground scar was located in a grassy area adjacent to a building, about 850 ft north of the damaged power pole. The airplane subsequently impacted the building, and the cockpit, cabin, and wings were nearly consumed by the postimpact fire; the aft empennage, which remained outside the building, was relatively intact. Examination of the airframe revealed no evidence of any anomalies with any of the airplane’s primary or secondary flight control surfaces. Additionally, the parking brake handle in the cockpit, and the respective valve that it controlled, were both found in the brake set position.

According to preliminary data recovered from the airplane’s flight data recorder (FDR), both thrust levers were set at 66°, and both engines remained at 91% N1 throughout the takeoff roll. While at an airspeed of about 100 knots, the elevator control surface position increased to a positive value, reaching about 16°. At this time the pitch of the airplane minimally changed to about +1°. The weight-on-wheels (WOW) indication remained in an on-ground state until beyond the departure end of the runway where the terrain began sloping downward. After departing the runway at an indicated airspeed of about 120 knots, the elevator position increased to a maximum recorded value of about 17° deflection, the airplane’s pitch rapidly increased to about +22°. Immediately thereafter the elevator position rapidly decreased to about -1.0° and the stick shaker (aerodynamic stall warning) activated.

The FDR data further indicated that at about the time the WOW indication transitioned from on-ground to an in-air state, the airspeed accelerated from about 120 knots to a maximum airspeed of 123.75 knots. Additionally, the right engine fuel flow, N1, and N2 decreased with corresponding ITT increase about 1.8 seconds after the WOW transition. Given the airplane’s velocity between these two times, the deceleration of the right engine occurred when it was in close proximity to the power pole.

Parking brake valve position and normal brake application were not recorded by the FDR, and the airplane’s takeoff configuration warning system did not incorporate parking brake valve position as part of its activation logic.

Further review of the FDR data revealed that the longitudinal acceleration values recorded during the takeoff roll of the accident flight (0.245g) were less than the recorded values for the airplane’s two previous takeoffs (0.365g and 0.35g). Additionally, the time the airplane took to accelerate from 20 to 100 kts during the accident flight and the previous two takeoffs were 17 seconds, 11.5 seconds, and 12 seconds, respectively. Additionally, the elevator position and pitch attitude of the airplane at rotation during its previous takeoff were about 13°, and +1.6°, respectively. The pitch attitude then continued to increase to +10° and remained at that value as the airspeed increased and the elevator position decreased.

The airplane’s cockpit voice recorder was retained for read-out and transcription.

Aircraft and Owner/Operator Information

Aircraft Make: Cessna 
Registration: N560AR
Model/Series: 560 XL 
Aircraft Category: Airplane
Amateur Built:
Operator: 
Operating Certificate(s) Held: None
Operator Designator Code:

Meteorological Information and Flight Plan

Conditions at Accident Site: VMC 
Condition of Light: Day
Observation Facility, Elevation: KBDL,175 ft msl
Observation Time: 09:51 Local
Distance from Accident Site: 17 Nautical Miles 
Temperature/Dew Point: 19°C /13°C
Lowest Cloud Condition: Scattered / 2700 ft AGL
Wind Speed/Gusts, Direction: 12 knots / , 350°
Lowest Ceiling:
Visibility: 10 miles
Altimeter Setting: 29.77 inches Hg
Type of Flight Plan Filed: IFR
Departure Point: Farmington, CT
Destination: Manteo, NC (MQI)

Wreckage and Impact Information

Crew Injuries: 2 Fatal 
Aircraft Damage: Destroyed
Passenger Injuries: 2 Fatal 
Aircraft Fire: Both in-flight and on-ground
Ground Injuries: 1 Serious, 3 Minor 
Aircraft Explosion: On-ground
Total Injuries: 4 Fatal, 1 Serious, 3 Minor 
Latitude, Longitude: 41.69761,-72.86326 

Those who may have information that might be relevant to the National Transportation Safety Board (NTSB) investigation may contact them by email witness@ntsb.gov, and any friends and family who want to contact investigators about the accident should email assistance@ntsb.gov. You can also call the NTSB Response Operations Center at 844-373-9922 or 202-314-6290.


12 comments:

  1. The report on the 560 that crashed in Farmington has come out and parking brake WAS on. Sure would be good to have the post restored, perhaps without names, photos or comments if that would satisfy the objections that got the posting cancelled.

    From a safety perspective, KR's posting about the parking brake issue could save some lives.

    ReplyDelete
    Replies
    1. Perhaps the preliminary report is as detailed as it is because NTSB intends to take action to mitigate the lack of indication for missed parking brake in affected S/N's.

      If parking brake left on was also the cause of the 2019 N91GY accident, that still open investigation was a missed opportunity to raise awareness on the lack of warning before N560AR's accident.

      http://www.kathrynsreport.com/2019/08/cessna-560xl-citation-excel-n91gy.html

      Delete
    2. I get your point, but does the FAA really need to be liable when someone misses a checklist item?

      Delete
    3. @Kenneth- You are correct that the pilot is responsible to perform the checklist, but at the moment, there is no confirmation that the before take-off checklist for N560AR included verification that the parking brake is disengaged.

      A Citation 550 accident in 2015 revealed that the parking brake was not included in that model's before take-off checklist. Got written up formally as a safety item to Cessna. Customer Support should have issued revision sheets to add parking brake checklist verification to all effected models and S/N's. Did they?

      http://www.atsb.gov.au/publications/investigation_reports/2015/aair/ao-2015-114/si-01/

      Delete
  2. Replies
    1. A missed checklist item, an unverified response to a checklist action item, or failure to utilize a checklist will probably result in nothing going wrong. However, that behavior might not produce the same outcome one unfortunate time. There are some very high profile accidents that were the result of missteps by professional flight crew. It's unfortunate that the parking brake is not included in the takeoff configuration logic.

      Delete
    2. How does this happen...? Complacency

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    3. ATSB (Australia) claimed in a 2015 550 accident report that the manufacturer’s before take-off checklist did not include a check to ensure the parking brake is disengaged.

      One big reason this accident scenario can happen is because the aircraft can taxi with the parking brake knob pulled out if trapped brake line pressure is low. The pull-out parking brake knob at the pilot's left knee can't easily be seen by the co-pilot and airframes configured the same as the accident aircraft don't have an indicator or logic to catch a forgotten parking brake.

      It is important to understand that while the parking brake valve functions by trapping applied brake line pressure at the wheels when the knob is pulled out, trapped pressure will increase if toe brakes are used during taxi with the Citation's parking brake on.

      The system design includes pass through check valves inside the parking brake valve so that toe brake application is not blocked in the INCREASE PRESSURE direction if the parking brake is forgotten. Had to be designed that way or there would be taxi accidents after leaving the ramp from not being able to use the toe brakes if the parking brake was still on.

      During takeoff roll, heating and expansion of multilayer brake packs while the parking brake valve holds trapped pressure produces increased brake drag. Anti-skid couldn't relieve trapped brake line pressure even if logic design covered the circumstances because the anti-skid valves are not located between the parking brake valve and the wheels.

      The Australian Transportation Safety Board report is linked below. The report has a photo of the pull knob control on a 550, includes some history and discusses concern over checklist and indication shortfalls. There is an analysis that explains failure to rotate the nose due to braking moment opposing elevator deflection.

      2015 Report PDF:
      http://www.atsb.gov.au/media/5770811/ao-2015-114-final.pdf
      Original link:
      http://www.atsb.gov.au/publications/investigation_reports/2015/aair/ao-2015-114/

      Delete
  3. If the parking brake was engaged, just their seat of the pants feel on reduced acceleration should have queued the crew to abort. Two presumed experienced pilots in type. I am aghast at how this has occurred on more than one occasion. And this runway being short for XLS+ ops would have me on top of acceleration performance behind the controls.

    I mean let's get real here:

    "Additionally, the time the airplane took to accelerate from 20 to 100 kts during the accident flight and the previous two takeoffs were 17 seconds, 11.5 seconds, and 12 seconds, respectively."

    Who here wouldn't notice that massive degraded acceleration or not be worried enough to abort on a 7,000' runway let alone one half that length? If their engine gauges were reading normally, which apparently they were, that means a hanging brake. That in and of itself is a danger after takeoff and retraction as overheated dragging brakes can cause an internal fire after which has happened and has brought down aircraft.

    ReplyDelete
    Replies
    1. Agreed. Any indication of degraded performance is an I. Ediate abort, I don't care what aircraft or what runway. Hope isn't a strategy.

      Delete
  4. same plane, same crew, same base, same customers, same schedules, etc creates repeated routines, most very good, sadly one missed instinctive routine response led to tragic outcome ... still can't understand the failure to feel something was very wrong !

    ReplyDelete
  5. This hazard could be completely eliminated if Citation pilots developed a habit of making a maximum effort toe brake press before starting takeoff roll.

    With the parking brake left on, the maximum effort toe brake press will go through the parking brake valve's internal pass-thru check valves and trap that level of brakes applied pressure at the wheels.

    Starting the takeoff roll after maximum effort toe brake pressure is trapped by the parking brake valve would either produce no movement or brake drag that is so high that no pilot would continue.

    ReplyDelete

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