10 Dead in Small Plane Crash at Dallas Area Airport

Incident report:

• Date: June 30, 2019
• Location: Addison Airport, Addison TX, USA
• Airline: Private
• Type of Aircraft: Beech King Air 350
• Type of Incident: Crashed on Takeoff
• Total Passengers: 8 + 2 Crew
• Fatalities: 10

(Addison Airport, Addison, TX, USA -July 1, 2019) On Sunday morning, June 30, 2019, a twin-engine turboprop powered Beech King Air 350 crashed on takeoff from the Addison Municipal Airport near Dallas, Texas. Eyewitnesses reported the following important information:

• The aircraft had just lifted off from the runway when it veered to the left and then dropped its left wing and crashed into an empty hanger;
• The aircraft looked like it was operating at a clearly reduced power output; and, “you could tell it couldn’t climb.”
• The aircraft rolled over before impacting the hanger.
• The plane did not sound “right” on takeoff.

There is much information that can be discerned from these factual observations. Most twin engine, fixed wing, propeller-driven aircraft produce power to sustain flight (aerodynamic lift) from an engine located on each wing. Beech King Air 350 aircraft are powered by two Pratt & Whitney turboprop engines located on the inboard section of each wing. If one engine fails, the other engine’s propellers will continue to produce power (thrust), however, the asymmetric thrust created from one operating and one failed engine will cause the airplane to quickly yaw toward the failed engine.

Pilot Control Critical in Engine Failure

In that circumstance, it is critical for the pilot to maintain directional control of the aircraft. To do so, the pilot faced with this emergency condition must immediately counter the adverse yaw by application of full opposite rudder, (in other words, depressing the rudder pedal that is located on the side of the operating engine). The rudder pedals are controlled by the pilot’s feet. If the left engine quits, the airplane will yaw to the left and the pilot will push down on the right rudder pedal; and if the right engine quits the airplane will yaw to the right and the pilot will push down on the left rudder pedal.

Airspeed is crucially important during this emergency flight maneuver. Another critical factor is that upon engine failure on a Beech King Air 350 aircraft, the propellers on the failed engine must “feather” by turning into a knife-like fixed position toward the relative air passing over the airplane. On the Beech King Air 350, the propellers on a failed engine should “auto feather” if the system is operating properly, however, the pilot must still use the rudder to maintain directional control of the airplane.

Aerodynamicists and design engineers calculate certain speed limitations for the safe and successful flight of an aircraft. The limitations applicable in the Addison, Texas, crash are called: VYSE, which is the indicated airspeed (velocity) for best single-engine rate of climb, also called “Blue Line”; VYXE, which is the indicated airspeed (velocity) for best single engine angle of climb; and, VMC, which is the minimum indicated airspeed needed to control the airplane in flight. Ideally, with an engine loss on takeoff, the pilot should maintain directional control and set the airplane speed at VYSE (Blue Line). Under no circumstances should the airspeed be allowed to decrease below VMC, (the slowest indicated airspeed at which a twin-engine aircraft can operate with one engine inoperative). As the airspeed decreases and approaches VMC, the yawing effect will become ever more pronounced and eventually, the wing with the powered engine will create more lift than the wing with the failed engine, causing the aircraft to roll over in what is commonly called a VMC roll. This phenomenon is most dangerous at takeoff.

Eyewitnesses reported that the plane did not sound right on takeoff, that the aircraft looked like it was at reduced power, that it veered left, and rolled over. These accounts all lead to a potential for failure of the left engine and a loss of directional control.

NTSB Investigation

The NTSB will invite Beechcraft (now owned by Textron, Inc.) and Pratt and Whitney to participate in the accident investigation and evaluate their products. The family of the victims of the crash will not be permitted to have a representative attend inspections of the wreckage or be privy to the findings and discussions among the NTSB, Beechcraft, and Pratt and Whitney. Instead, Beech and Pratt & Whitney, potential defendants in any litigation arising from the crash, will have the first chance to evaluate their products and provide their recommendations to the NTSB on the question of its determination of the probable cause of the accident. Fortunately for the victims of this tragedy, the U.S. Congress enacted a law that renders the final conclusions of the NTSB inadmissible in any civil litigation.

Written by Bradley Stoll