Aviation Accident Summaries

Aviation Accident Summary FTW99LA084

MESQUITE, TX, USA

Aircraft #1

N3819D

Beech BE-76

Analysis

During a night landing with a simulated right engine failure, the multi-engine rated instrument student flared 'higher than normal.' The airspeed decreased to 'approximately 68 knots,' near the airplane's minimum control speed of 65 knots. The flight instructor (CFI) called for the student to add power. The student increased the power to the left engine only. The CFI was unaware that power was applied on only one engine until the airplane went out of control and turned to the right. The CFI attempted to regain control; however, the right wing struck the ground on the right side of the runway. The CFI stated that a breakdown in communication and the time of day were both significant factors. After the student placed both prop controls full forward during final approach, the CFI assumed, but did not verbally confirm, that the student was making a normal approach and landing. He was unable to see that the student was only grasping the left throttle due to the lack of light in the cockpit.

Factual Information

On February 19, 1999, at 1920 central standard time, a Beech BE-76 twin engine airplane, N3819D, impacted terrain following a loss of control during a simulated single engine landing near Mesquite, Texas. The airplane was owned by a private individual and operated by Ari-Ben Aviators, Ft. Pierce, Florida. The commercial pilot/instrument flight instructor was not injured and the private pilot/instrument student received minor injuries. The airplane sustained substantial damage. Night visual meteorological conditions prevailed for the instrument instructional flight conducted under simulated instrument conditions. A flight plan was not filed for the Title 14 Code of Federal Regulations (CFR) Part 91 flight. The flight departed Addison, Texas, approximately 1830. According to the Pilot/Operator Aircraft Accident Reports (NTSB Form 6120.1/2) submitted by the flight instructor and the instrument student, at the time of the accident, the flight instructor and instrument student had accumulated 227.0 hours and 33.8 hours respectively in multiengine aircraft. The flight instructor's time included 125 hours of instruction given in multiengine aircraft. After departing Addison Airport, the instrument student and flight instructor proceeded to the Mesquite Metro Airport. The flight instructor stated that, after monitoring the Common Traffic Advisory Frequency for the Mesquite Metro Airport, he determined that the weather "conditions were VFR with a reported wind of 7 knots from the southeast." Both the flight instructor and instrument student reported that dark night conditions prevailed at the time of the accident. According to the National Weather Service surface observation for Dallas Love Field (24 nautical miles northwest of Mesquite Metro Airport) at 1753, the wind was from the southeast at 8 knots with 10 statute miles visibility. The flight instructor instructed the student to perform the "full procedure Localizer Back Course for runway 35, circle to land runway 17." While on the outbound leg of the back course approach, the flight instructor simulated a failure of the right engine by setting "the right engine manifold pressure to 10 inches" and "the right engine propeller control to 2000 RPM." The instrument student proceeded to complete the approach with the right engine simulated inoperative. Upon reaching the missed approach point, the flight instructor directed the instrument student to "remove his view limiting device (hood) and execute the circle to land maneuver." The instrument student made a right turn and entered the left downwind entry for runway 17. The instrument student proceeded to perform the landing with a simulated failure of the right engine. After crossing the "runway threshold", on final approach, the flight instructor noticed that the aircraft's speed was "indicating approximately 68 knots and decreasing, and the rate of descent began to increase." The flight instructor told the student to add power. According to the flight instructor, the instrument student "failed to add sufficient power to slow the descent rate." The flight instructor then "called loudly and emphatically, power, power, power." The flight instructor further stated, "as the aircraft crossed the threshold at approximately 30-40 feet on the final approach, the pilot began a roundout maneuver higher than normal." After yelling "power, power, power," he "heard engine power increasing rapidly." The aircraft then rolled into a right bank of approximately 45 to 50 degrees at which point the flight instructor attempted to take control of the aircraft. The flight instructor increased power on the right engine while applying left aileron and left rudder. He stated that "the aircraft initially failed to execute a roll back to the left, so I then reduced the power on the left engine and held the right throttle control full forward." The flight instructor further stated that the aircraft "immediately began to correct towards a wings level attitude and the right wing was still coming up as we contacted the ground to the right of runway 17, heading approximately 45 degrees off runway heading in a nose low attitude." According to the statement submitted by the instrument student, the flight instructor called for him to add power "six or eight times in total." At this point the instrument student estimated the aircraft to be 15 feet above the runway. He added, "Immediately after I pushed the throttle most of the way forward [the flight instructor] yelled "My Airplane". After [the flight instructor] grabbed the yoke, we veered to the right." The aircraft then rolled to a 30 to 35 degree bank and began heading to the right. The instrument student also stated that he "believe[d] that the right wingtip struck the ground first." According to the FAA Approved Airplane Flight Manual for the Beechcraft Duchess 76, the One Engine Inoperative Final Approach speed is 85 knots (minimum). Also, the minimum controllable indicated airspeed for this airplane is 65 knots. Examination of the airplane by the FAA inspector revealed structural damage to the wings. Other damage included a cracked windshield, collapsed left main and nose landing gear, separated left propeller, bent right propeller, separated right wingtip and damaged nose section. No fire was reported. In a letter dated December 20, 1999, the flight instructor stated that he "did not (attempt to) take control until such time as the aircraft departed controlled flight due to asymmetrical thrust applied by the instrument student who was flying the airplane." He further stated that he was "unaware that [the student] was applying power on only one engine until the aircraft went out of control." According to the flight instructor, the simulation of the engine failure had ended when the student placed both propeller controls in the full forward position after the airplane was established on final approach. Regarding how the accident might have been prevented, the instructor stated the following: The breakdown in communication and time of day were both significant factors. After briefing the instrument student to "place the prop controls full forward during final approach," I assumed he was performing the landing under normal circumstances after he placed the prop controls forward and maintained a normal approach speed. I believe he may have failed to grasp the right throttle during final due to the fact that he had regulated power with only the left throttle during the entire approach. The throttle levers on the BE-76 are extremely close together. The instrument student's hand was covering both throttle handles just before he applied power to the left engine during the flare. It is now apparent that he only had a grasp on the left throttle lever. However, I was not able to see his actual grip on the throttles due to their close proximity, the lack of lighting in the cockpit and the fact that we did not continue to communicate throughout the final approach.

Probable Cause and Findings

The flight instructor's inadequate supervision of the multi-engine rated instrument student during a simulated single engine landing, resulting in loss of control of the airplane. Factors were the dark night light condition, the flight instructor's inadequate communication with the student, and the student's improper use of the throttle control.

 

Source: NTSB Aviation Accident Database

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