Plane & Pilot
Tuesday, November 6, 2012

Adequate Airspeed

Fundamental failures by pilots still figure in some accidents

We've just about come to the end of another year in which the NTSB continued to fill its files with accident reports that read suspiciously like many of the thousands it already has on file. Among the immutable truths in aviation is that an aircraft won't stay aloft without airspeed, and pilots who fail to properly manage that element are in for a rude awakening. Even the growing sophistication of aircraft in the general aviation fleet won't help in risk management and accident avoidance when fundamentals of flight are overlooked. It doesn't matter whether you're flying a Cub or an Airbus, you need sufficient airspeed so the airplane's wings will continue to produce adequate lift and the control surfaces will still provide effective control. A recent batch of finished investigations from the NTSB contained three accidents in which lack of adequate airspeed played a critical role. Adding to the airspeed enigma is that the accident aircraft represented here required different levels of training and skill, and the pilots involved represented a wide spectrum of experience.

Cessna 402B
The twin-engine airplane was on a flight from White Plains, N.Y., with a planned destination of Portland, Maine. Earlier in the day, it had flown from Portland to Nantucket, Mass., then to White Plains. At about 6:15 p.m., while it was still daylight, the airplane crashed into a house near Biddeford, Maine. The ATP-rated pilot was killed. The pilot had logged 5,010 total hours with 120 hours in Cessna 402B aircraft. Visual meteorological conditions prevailed.

While airborne and receiving flight following services, the pilot asked ATC to change his destination to the Biddeford Municipal Airport. The pilot was subsequently advised by ATC that his destination had been updated and radar services were being terminated. He was told to squawk 1200 (VFR). FAA radar data revealed that the airplane overflew the south end of the Biddeford Airport at approximately 1,000 feet MSL and turned left, as if entering the left downwind leg of the airport traffic pattern. However, it continued well beyond the point at which a turn to a left base would have been made. When it was approximately two miles from the approach end of runway 24, the airplane was observed on radar turning right and completing a loop across the ground, resulting in a reversal of direction. The airplane then maneuvered slightly to just about line up with the extended centerline of the runway, although it wasn't holding a steady heading. The last radar data indicated an altitude of 400 feet MSL and a ground speed of 69 knots.

The airplane impacted four trees. It came to rest on the roof of a house that was located approximately 1,491 feet to the northeast of the runway 24 threshold. A fire broke out. The left engine was in the house. The right wing and engine were visible above the roof line. The right main landing gear was in the down and locked position. The left main and nose gear were found in the residence.The wing flaps were found in the extended position.

The engines were sent to the manufacturer in Mobile, Ala., for examination. The left engine was too damaged for a test run. It was disassembled and no pre-accident mechanical malfunctions or failures were found that would have precluded normal operation.

The right engine was examined and mounted on an engine test stand. Approximately 20 minutes into the test, the engine sustained a partial loss of power. Additional testing determined that O-rings in the engine's throttle and control assembly had been improperly installed.


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