Beech King Air 200, Seattle, Wash., April 8, 2001–“The pilot’s failure to properly follow pre-takeoff checklists…and his subsequent failure to properly perform a manual landing-gear extension, resulting in a landing with the gear not down and locked” is the introduction to the probable cause of this gear collapse accident. The NTSB also blamed the “FAA-approved airplane flight manual (AFM),” saying the book “does not contain information on how long to pump the manual extension handle for a down-and-locked condition in the event the gear’s green down lights do not illuminate.”
They do not illuminate, for instance, after the dual generator failure that follows the omission of two items on the startup checklist–turn off both starters. According to the NTSB’s final report, the AFM’s dual generator failure checklist does not “contain a step for checking the engine ignition/start switches on the off position prior to attempting generator reset.” The NTSB notes that the FAA has inadequately approved both procedures in the AFM.
The pilot, who was new to King Airs, with 26 hr (11 PIC) in make and model, recounted the afternoon’s events to the NTSB. He stated that shortly after takeoff from Boeing Field in Seattle, both DC generator caution lights illuminated on the annunciator panel. Seattle Approach confirmed the pilot’s suspicions of the impending electrical failure when they informed him that his transmissions were barely readable. He declared an emergency and turned back toward Boeing Field.
He selected gear down but, as an electric motor drives a mechanical chain drive to the gear linkage that operates the gear, nothing happened. The pilot then attempted to lower the gear manually, but with the electrical failure he had no way of confirming the three-green illumination. He did, however, see the nose gear in the nacelle mirror and felt it was in a “gear down and vertical” position. The pilot reported that the gear “sagged” to a collapsed position as he touched down on Boeing Field’s Runway 31L.
Operated by Wild Angels, a Santa Fe, N.M.-based environmental/ecological organization, the King Air sustained substantial damage when the gear collapsed. The five passengers and pilot were not hurt in the event.
While recounting the incident to the NTSB, the pilot could not recall placing the engine ignition/start switches back to the off position at the completion of the engine start sequence. The pilot should turn the starter switches into the off position at a minimum engine N1 RPM of 50 percent. In the FAA-approved King Air 200 AFM, the “generator inoperative (DC gen annunciator light on)” procedure tells the pilot to turn the generator to the off position, reset and then on. It then specifies that if the generator will not reset, turn the generator switch off and do not exceed 100-percent load on the operating generator. It does not specifically state that the engine ignition/start switches should be checked to ensure they are in the off position.
To accomplish the landing-gear manual extension, the AFM states the pilot should pump until “three green” or until sufficient resistance is felt, if no power exists to verify the three-green illumination. The manual also contains the following: “Caution: do not continue pumping after receiving three green lights (gear down indication). Further movement of the handle could damage the drive mechanism.” Sufficient resistance is not defined.
The NTSB reports that SimCom training material found in the aircraft mirrors the AFM: “If for some reason the gear does not indicate down and locked, continue pumping the lever until sufficient resistance is felt to be sure that the gear is down and locked.” A SimCom checklist, found in the aircraft with the warning “For Simulator Training Purposes Only,” states the same procedure.
Investigators checked the aircraft’s battery in the as-found condition and it failed a capacity check. They then charged the battery, reinstalled it in the aircraft and successfully started the right engine. Investigators didn’t repeat the process on the left engine as the nacelle and fuel tank sustained extensive damage in the accident.
