19980222003769I

Narrative: on February 22, 1998, at 1021 central standard time, a Saab 340B transport airplane, N396AE, operated by simmons airlines, inc., as American eagle flight 509, experienced a collapsed left main landing gear while landing at the Lawton-fort sill regional airport, near Lawton, Oklahoma. The flight which originated at the dfw international airport at approximately 0941, was being operated under title 14 CFR part 121. The airplane sustained minor damage and there were no injuries to the 3 passengers and 3 crewmembers aboard the airplane. Visual meteorological conditions prevailed and an IFR flight plan was filed for the scheduled flight. According to preliminary information provided by the operator, the flight crew reported that while en route to Lawton, they smelled the odor of electrical heat and discovered that the gear control circuit breaker had popped. The flight crew notified their company's maintenance operations center by radio and after discussing all their options, elected to continue on to Lawton, which is one of the company's maintenance bases. After resetting the popped circuit breaker, the landing gear selector was placed in the down position and the crew received indications that the nose landing gear was "down and locked" and the two main gears were unsafe. The flight crew initiated emergency procedures to extend the hydraulically operated landing gear by alternate means. The crew elected to execute three tower fly-bys to verify the position of the two main landing gears, which visually appeared to be down and locked from the cabin; however, were indicating to be "unsafe" in the cockpit. After the third tower fly-by, the airplane was cleared to land on runway 35 with emergency equipment standing by. Witnesses at the airport reported that the left main landing gear collapsed as soon as weight was placed on the landing gear soon after touchdown. The airplane slid off the runway and came to rest in a muddy area approximately 2,500 feet from the touch down point, about 75 feet west of the runway. All occupants exited the airplane safely through the left over wing exit. No fire was reported. Examination of the airplane by the FAA inspector confirmed damage to the left flap, cowling, landing gear doors and propeller. (-23)a Saab 340B (N396AE) experienced a gear motor malfuncation in flight r esulting in an unsafe gear indication. After approriate emergency procedures were completed the aircraft landed and the left main gear collapsed. The aircraft slid off the runway approximately 2500 feet from touchdown. The crew and passengers exited safely. (.4)during cruise flight, the flight crew reported smelling an odor similar to burning/smoldering electrical equipment and noticed that the landing gear control circuit breaker had popped. The flight crew consulted the company's quick reference handbook (qrh). The qrh addressed hydraulic problems and failed to discuss possible electrical problems related to the operation of the landing gear. The company's maintenance facility was appraised of the situation; however, the maintenance person on duty was not able to assist the flight crew. Three tower fly-bys were made. The flight attendant and tower personnel reported that the landing gear appeared to be down and the gear doors were closed. The flight crew elected to land with the light on the gear handle indicating an 'in-transit' condition and the two main landing gear indicators in the 'unsafe' condition. The left main landing gear on th e twin-engine transport category airplane collapsed during the landing roll. Examination revealed that the weight-on-wheels relay, which is located in the avionics bay directly under the captain's station, shorted, and as a result, the landing gear control circuit breaker popped. The electrical short was attributed to the spill of a soda can on the flight deck on a previous flight. The investigation revealed that the cockpit floor was not carpeted or sealed to prevent fluids/moisture from seeping into the electrical compartment beneath the cockpit floor. A review of the emergency extension system for the airplane revealed that the landing gear could have been extended if the fight crew had pulled the emergency extension handle.