N87297Cessna 310R · 1975

On June 30, 2017, about 0935 Pacific daylight time, a Cessna 310R airplane, N87297, was substantially damaged when it was involved in an accident near Santa Ana, California. The pilot and passenger sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that he checked that both fuel selectors were in the “main” position before starting the engines and during run-up and that they remained in that position throughout the flight. Shortly after departure from John Wayne-Orange County Airport (SNA), Santa Ana, California, and when the airplane was about 400 ft above ground level (agl) with the flaps in the 15°-down position, the right engine lost power. He subsequently transmitted a “mayday” to the air traffic control tower, and a controller then cleared him for landing back at the airport. The pilot then feathered the right propeller, and the airplane was able to maintain an altitude of between about 400 and 500 ft agl as he turned it right onto the downwind leg of the traffic pattern.

According to radar data, the airplane maintained a ground speed of between 95 and 102 knots throughout the downwind leg as it slowly neared the runway. The pilot stated that, after turning onto the downwind leg, the controller informed him that the landing gear were retracted. The pilot replied that he knew the landing gear were up and that he would lower them on the final approach leg. During the turn to final, the pilot lowered the landing gear, and the airplane started to descend. The radar track showed the airplane turning right for the final approach at a ground speed of 93 knots, which decreased to 81 knots. After the pilot realized that the airplane was not going to be able to reach the runway, he prepared for a forced landing on a freeway. The airplane subsequently impacted the freeway’s center median.

A video provided by a witness showed the airplane in a right-wing-low, 45 bank in a slightly nose-high attitude and descending rapidly toward a freeway from the north with the landing gear down. The wings then leveled as the airplane crossed over the freeway about 20 ft agl. The airplane momentarily exited the camera’s view before reappearing impacting the center median divide and opposing lane, followed by fuel spraying from the airplane and subsequent explosions. A security camera video also showed the airplane rapidly descending with the left wing down and the nose high, followed by the left wing impacting the center median divide. Several eyewitnesses reported that they saw the airplane approaching from the northwest, making a right turn, and then suddenly losing altitude. Two witnesses stated that the airplane banked left just before impacting the ground.

The debris field was about 150 ft long and crossed over the north- and south-bound lanes of the freeway. The main wreckage was partially consumed by fire, and both engines and propellers remained attached. The horizontal stabilizer had separated from the wreckage and was found farther down the debris field. The airplane had impacted several moving vehicles, and one truck impacted the main wreckage.

Postaccident examination revealed that the left and right fuel selector valve handles were in the “main” and “auxiliary” positions, respectively. The left fuel selector valve was found in the “main” position, and the right fuel selector was found pulled past the “off-stop” position. All fuel caps were found, and the fuel tank filler necks were installed with restrictor orifices.

Both wing tip tanks had separated from the wings and were found in several sections. The right wing exhibited impact and thermal damage. About 5 ft of the right-wing tip had separated from the wing. The leading edge was crushed from the wing root to the separated tip area. The left wing exhibited impact and thermal damage. About 1 ft of the left-wing tip structure had separated from the wing.

The rudder remained attached, and the top half was bent down and right. The horizontal stabilizer had separated from the empennage. Cable control continuity was established to the tail section and both ailerons. The flaps and flap chain drive were found in the 15°-down position. The landing gear were found in the down position. The propeller assemblies exhibited impact damage consistent with a low-power setting during impact sequence.

Postaccident examination of the airframe, engines, and propeller assemblies revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation.

Nonvolatile Memory Data

A review of engine monitor data revealed that, about the time of departure, both engines’ fuel flow and cylinder exhaust gas temperatures (EGT) increased. As the fuel flow started to level out over the next 30 seconds, the right engine’s fuel flow fluctuated, followed by the left engine fuel flow fluctuating. The right engine’s fuel flow decreased to near 0, and the left engine’s fuel flow returned at a lower rate before fluctuating again near the end of the data. The right engine’s EGT decreased, followed by three cylinders’ EGTs increasing near the end of the data.

Maintenance History

A review of the maintenance records revealed that, on May 12, 2017, the fuel selector valves were removed and replaced with repaired units. According to onboard flight documents, the airplane had accrued 8.9 flight hours, consisting of three flights, since the fuel selector valves were replaced.

Engine Failure Emergency Procedures

Pilot’s Operating Handbook (POH)

The POH, Engine Failure After Takeoff, checklist stated, in part, the following:

Mixtures – AS REQUIRED for flight altitude.

Propellers – FULL FORWARD.

Throttles – FULL FORWARD.

Landing gear – CHECK UP.

Inoperative Engine:

Throttle – CLOSE.

Mixture – IDLE CUT-OFF.

Propeller – FEATHER.

Establish Bank – 5° toward operative engine.

Wing Flaps – UP, if extended, in small increments.

Climb to Clear 50-Foot Obstacle – 92 (Knots Indicated Airspeed) KIAS.

Climb at Best Single – Engine Rate-of-Climb Speed – 106 KIAS at sea level; 94 KIAS at 10,000 feet.

Trim tabs – ADJUST 5° bank toward operative engine with approximately 1/2 ball slip indicated on the turn and bank indicator.

Cowl Flap – CLOSE (Inoperative Engine).

Inoperative Engine – SECURE as follows:

Fuel Selector – OFF (Feel For Detent).

Auxiliary Fuel Pump – OFF.

Magneto Switches – OFF.

Alternator Switch – OFF.

As Soon as Practical – LAND.

The FAA's Airplane Flying Handbook states the following:

The basic difference between operating a multiengine airplane and a single-engine airplane is the potential problem involving an engine failure. The penalties for loss of an engine are twofold: performance and control. The most obvious problem is the loss of 50 percent of power, which reduces climb performance 80 to 90 percent, sometimes even more. The other is the control problem caused by the remaining thrust, which is now asymmetrical. Attention to both these factors is crucial to safe one engine inoperative (OEI) flight. The performance and systems redundancy of a multiengine airplane is a safety advantage only to a trained and proficient pilot.

Although it is a natural desire among pilots to save an ailing engine with a precautionary shutdown, the engine should be left running if there is any doubt as to needing it for further safe flight. Catastrophic failure accompanied by heavy vibration, smoke, blistering paint, or large trails of oil, on the other hand, indicate a critical situation. The affected engine should be feathered and the Securing Failed Engine checklist completed. The pilot should divert to the nearest suitable airport and declare an emergency with ATC for priority handling.

There are two different sets of bank angles used in OEI flight.

1. To maintain directional control of a multiengine airplane suffering an engine failure at low speeds (such as climb), momentarily bank at least 5° and a maximum of 10° towards the operative engine as the pitch attitude for VYSE [best rate of climb speed with OEI] is set.

2. To obtain the best climb performance, the airplane must be flown at VYSE and zero sideslip with the failed engine feathered and maximum available power from the operating engine. Zero sideslip is approximately 2° of bank toward the operating engine and a one-third to one-half ball deflection also toward the operating engine. If above the airplane's single-engine ceiling, this attitude and configuration results in the minimum rate of sink.