History of Flight
On August 20, 2008, at approximately 1230 eastern daylight time, a Cessna 441, registration N441VB, experienced a runway excursion during an aborted takeoff at Baltimore/Washington Thurgood Marshall Airport (BWI), Baltimore, Maryland. The pilot and three passengers were uninjured. The flight was operated under 14 CFR Part 91 for personal purposes, with visual meteorological conditions prevailing and an instrument flight rules flight plan filed.
According to the pilot, the inbound flight and pre-takeoff procedures were normal. During the takeoff roll, the airplane moved slightly to the left. The pilot added power on the left engine, but the airplane continued left, and the left wheel departed the left edge of the runway pavement. The pilot aborted the takeoff and manipulated the engine power levers to correct direction, but the airplane veered left, completely left the paved surface, and struck an earthen mound. The nose landing gear fractured, and the airplane came to rest approximately 2,500 feet beyond the start of the takeoff roll. The pilot shut down the engines, and all occupants exited via the main door. Airport rescue and fire fighting personnel responded and partially foamed the airplane to prevent a fire.
Personnel Information
The pilot held a private pilot certificate with single-engine land, multi-engine land, and instrument ratings. He reported 2,485 total flight hours, including 1,473 hours in the accident airplane make and model. In the 30, 60, and 90 days preceding the accident, he logged 3, 27, and 55 hours respectively, all in the accident airplane. His most recent flight review was completed in April 2008 in a Cessna 441 flight simulator, and his most recent FAA third-class medical certificate was issued in March 2007.
Aircraft Information
The airplane was a low-wing turboprop equipped with two Garrett TPE331-10N turbine engines and McCauley "BlackMac" four-blade, full-feathering, reversible propellers. It was manufactured in 1980 and purchased by the current owner in 2000. The most recent 100-hour inspection was completed in February 2008 at a total time in service of 3,963 hours.
Engine and Propeller Controls
The principal controls included a power lever and condition lever for each engine/propeller. Each engine had a dedicated fuel computer and fuel control unit. The power and condition levers were electrically linked to the fuel computer, which was electrically linked to the fuel control unit; the power lever was also mechanically linked to the fuel control unit. The engine had two operating modes: normal and manual. The accident takeoff was conducted with engine switches in normal mode.
The propeller had two operating modes: beta and propeller-governing. Beta mode was for ground operation; propeller-governing mode was for flight. The power lever controlled fuel flow either electrically (normal mode) or hydro-mechanically (manual mode). Propeller start locks were designed to hold blades in low pitch for engine start, engaging when the propeller was moved to reverse after fuel cutoff at shutdown.
Cockpit Annunciator Panel
The annunciator panel had 20 lights, including amber beta lights for each engine. According to the information manual, beta lights illuminated when the propeller was capable of being reversed, which was normal during ground operation. The beta light activation was based on a governor oil pressure sensing switch and did not indicate start lock status.
Wreckage and Impact Information
Runway 33R at BWI was 5,000 feet long and 100 feet wide, concrete and dry. The airplane came to rest about 2,500 feet from the takeoff start point and 200 feet west of the runway edge. The nose landing gear was fracture-separated; the nose, lower fuselage, and wings sustained crush and scrape damage. Engine mounts and nacelles were deformed. All propeller blades were scraped and bent; some propeller-drive and control components were fractured or bent.
Propeller Examination
Examination at McCauley Propeller Systems revealed that the left propeller assembly was found in the start lock position, with blade damage consistent with a negative blade angle at impact. The right propeller blades showed damage consistent with operating under power. No defects or evidence of malfunction were found in the left propeller start lock components. The propeller manufacturer representative concluded that the pilot did not properly unlock the left propeller after engine start.
Additional Information
The airplane was not equipped with any dedicated indication of start lock engagement. The pilot stated that engine start and taxi-out were normal and that he did not observe unusual indications prior to the takeoff roll, but he did not explicitly state whether he verified both propellers could be reversed after engine start.
Weather recorded at BWI at 1254 included variable winds at 3 knots, visibility 10 miles, few clouds at 6,000 feet, temperature 24°C, dew point 11°C, and altimeter 30.23 inches of mercury.