CEN16FA172

The pilot's failure to promptly feather the left propeller upon the initial loss of engine power shortly after takeoff and his failure to maintain airspeed while maneuvering with one engine inoperative, which resulted in a loss of control at a low altitude. Also causal was the partial loss of left engine power during initial climb for reasons that could not be determined because examination of the airplane did not reveal any evidence of mechanical malfunction that would have precluded normal operation.

The commercial pilot was conducting a checkride in the multi-engine airplane with an airline transport pilot-certificated designated pilot examiner. The pilot reported that, during the initial climb after takeoff, the left engine experienced a partial loss of power. At this time, the airplane was climbing at its single-engine best rate-of-climb speed (Vyse). The pilot reported that he was able to maintain control of the airplane with partial right rudder and right aileron inputs, and chose not to shut down and secure the engine because it was still providing "positive thrust." The examiner reportedly agreed with the decision to keep the engine running and to make left turns in the traffic pattern due to the increased number of landing options in that direction. The left turns, toward the partially running left engine, would have decreased the directional control of the airplane. While on the downwind leg of the traffic pattern, the left engine lost further power, and the pilot then attempted to feather the left propeller. Although he moved the left propeller control full aft, the propeller did not feather. Radar data indicated a continual loss of airspeed as the airplane turned from the upwind to downwind leg and from the downwind leg toward the airport. The airplane reached a maximum altitude about 255 ft above ground level on the downwind leg. As it turned toward the airport, the airplane collided with terrain in a 45° left bank and slight nose-down pitch attitude and was subsequently destroyed by a postcrash fire. The postaccident airframe, engine, and propeller examinations did not reveal any evidence of a mechanical malfunction that would have prevented normal operation; however, the airplane sustained significant postimpact fire damage, which prevented a full assessment of the fuel system and its configuration at the time of the accident. Examination of left propeller determined it was not in a feathered position at the time of impact, and that both blades appeared to be at or near the start lock position. The propeller was equipped with start locks that engaged below 800 rpm to prevent feathering of the blades during engine shutdown on the ground. In the event of an in-flight engine shutdown, the propeller must be feathered before engine speed decays to 800 rpm. It is likely that the pilot allowed the left engine rpm to decay below the start lock engagement speed, which prevented the propeller from feathering and, instead, remain windmilling. This would have resulted in a large amount of parasitic drag and a significant decrease of the airplane's single-engine climb performance. Due to the windmilling propeller, it is likely that the airplane would not have been able to maintain altitude even if the pilot had maintained Vyse; however, the pilot should have maintained this speed to minimize altitude loss and maintain controllability of the airplane. As the pilot maneuvered the airplane back toward the airport, he allowed the airspeed to decay such that the airplane no longer had the flight control authority to counteract the yaw and roll produced by the operating right engine, which resulted in a loss of control at a low altitude.

ORK, a public airport located about 4 miles north of North Little Rock, was owned and operated by the City of North Little Rock, Arkansas. The airport field elevation was 545 ft msl. The airport was served by two runways, runway 5/23 (5,002 ft by 75 ft, concrete) and runway 17/35 (3,019 ft by 75 ft, asphalt). The airport was not equipped with an air traffic control tower. According to Hartzell Propeller Owner's Manual No. 115N, the constant-speed propellers were hydraulically operated with feathering capability. Oil pressure provided by the propeller governor was used to move the blades toward low pitch (blade angle). A feathering spring, counterweights, and an air charge moved the blades toward high pitch and into feather in the absence of governor oil pressure. The propellers were also equipped with spring-energized latches (start locks) to keep the propeller blade angle low to minimize torque during engine start. The start locks engage the feathering high pitch stops when engine speed decreases below about 800 rpm. According to the propeller manufacturer, for a propeller to be found on the start locks after an accident, the propeller blade angle at impact was either at or below the start lock angle when engine speed decreased below 700-900 rpm, or the blade forces during impact moved the blade angle into a start lock position after engine speed decreased below 700-900 rpm. FAA Special Airworthiness Information Bulletin No. CE-05-51 describes a scenario in which the propeller of an inoperative engine did not feather because the windmilling speed had decreased below the propeller's start lock engagement speed. The bulletin states that a windmilling propeller produces a large amount of parasitic drag in a twin-engine airplane with one engine inoperative, which can result in the airplane's total drag exceeding the power available and an inability to maintain level flight. The Cessna 310F Owner's Manual states that, in an event of a loss of engine power shortly after liftoff, a pilot should maintain the Vyse speed of 111 mph unless there are obstructions which require a steep climb to avoid. The manual further stipulates that allowing the airspeed to fall below the Vxse speed of 95 mph would reduce or eliminate the airplane's ability to climb with one engine inoperative. The Cessna Pilot Safety and Warning Supplements states that, in event of a loss of engine power during takeoff, "prompt retraction of the landing gear, identification of the inoperative engine, and feathering of the propeller is of utmost importance if the takeoff is to be continued." The supplement further states that a windmilling propeller will severely degrade climb performance with one engine inoperative. Additionally, the supplement states that if an immediate climb is not necessary for obstacle clearance, a pilot should maintain Vyse, because it will provide the best chance of climb or least altitude loss during single-engine flight. A postaccident review of available meteorological data established that day visual meteorological conditions prevailed at the accident site. The nearest aviation weather reporting station was located at Bill and Hillary Clinton National Airport/Adams Field (LIT), Little Rock, Arkansas, about 7.7 miles south-southeast of the accident site. At 1253, about 38 minutes before the accident, the LIT automated surface observing system reported wind from 320° at 13 knots with wind gusts of 19 knots, 10 miles surface visibility, few clouds at 25,000 ft agl, temperature 24°C, dew point 5°C, and an altimeter setting of 30.01 inches of mercury. At 1353, about 22 minutes after the accident, LIT reported wind from 340° at 7 knots, surface visibility 10 miles, few clouds at 4,500 ft agl, temperature 25°C, dew point 5°C, and an altimeter setting of 29.99 inches of mercury. The Arkansas State Crime Laboratory, Little Rock, Arkansas, performed an autopsy on the pilot examiner. The cause of death was attributed to thermal injuries sustained during the accident. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology tests on specimens obtained during the autopsy. The pilot examiner's toxicology results were negative for carbon monoxide, ethanol, and all tested drugs and medications. --- Pilot --- According to FAA records, the 30-year-old pilot held a commercial pilot certificate with single-engine land, multi-engine land, and instrument airplane ratings. He was type-rated for the Mitsubishi MU-300 and Hawker 400 twin-turbofan business jets. His most recent FAA first-class medical certificate was issued on November 25, 2015, with no restrictions or limitations. The pilot's application for the airline transport pilot certificate, dated May 4, 2016, listed a total flight time of 950 hours, of which 612 hours were accumulated in multi-engine airplanes. He reported 377 hours of flight experience as pilot-in-command, 194 hours at night, 162 hours in instrument conditions, and 4 hours in Cessna 310F airplanes. The pilot was a captain with the Air National Guard who typically flew four-engine turboprop Lockheed C-130 airplanes. According to available records, the pilot's most recent military flight was flown on April 9, 2016, in a Lockheed C-130H3 airplane. --- Pilot Examiner --- According to FAA records, the 56-year-old pilot examiner held an airline transport pilot certificate with a rating for airplane multi-engine land and commercial privileges for airplane single-engine land and sea. He was type-rated for the Cessna 500, Cessna 560XL, Cessna 650, Dassault Falcon 50, and Dassault Falcon 900 business jets. He also held a flight instructor certificate with airplane single- and multi-engine and instrument airplane ratings. His most recent FAA second-class medical certificate was issued on July 24, 2015, with a limitation for corrective lenses. His initial authorization as an FAA designated pilot examiner was on September 28, 1995, and his latest examiner renewal was approved by the FAA on January 21, 2016. He was designated an examiner for private, commercial, instrument airplane, air transport pilot, flight instructor, flight instructor renewals, sport pilot, and sport pilot instructor certificates. He was authorized to administer checkrides in single-engine land airplanes, single-engine sea airplanes, and small multi-engine airplanes. The pilot examiner's flight history was established using his logbook. The final logbook entry was dated May 2, 2016, at which time he had accumulated 12,214 total hours of flight experience. He had logged 11,967.2 hours as pilot-in-command, 4,217.4 hours in single-engine airplanes, and 7,918.3 hours in multi-engine airplanes. He had accumulated 1,405.7 hours at night, 1,121.9 hours in actual instrument conditions, and 111.9 hours in simulated instrument conditions. He had flown 80.6 hours during the year before the accident, 74.4 hours during the 6 months before the accident, 57.2 hours during the 90 days before the accident, and 17.2 hours during the month before the accident. There was no record that he had flown during the 24 hours before the accident. The examiner had flown 20.2 hours in the accident airplane make/model during year before the accident. His most recent flight review, as required by 14 CFR 61.56, was completed on April 17, 2016. The airplane, serial number 310-0070, was manufactured in 1961 and was a low-wing monoplane of conventional aluminum semimonocoque construction. The airplane was powered by two 260-horsepower, 6-cylinder, Continental IO-470-D reciprocating engines. The engines provided thrust through two constant-speed, full-feathering, two-blade, Hartzell HC-C2YF-2CUF propellers. The five-seat airplane was equipped with a retractable tricycle landing gear and wing flaps and had a maximum allowable takeoff weight of 4,830 pounds. The airplane had two fuel tanks, one located at each wingtip, and a total fuel capacity of 100 gallons. T