HAWKER SIDDELEY DH.125-1F, SEATTLE, WASH., DEC. 16, 2002–The NTSB determined that the probable cause for this accident was the crew’s failure to verify that the landing gear was down and locked before landing; failure to follow the checklist and an inoperative landing-gear warning horn were cited as factors. At approximately 7:07 p.m. PST Hawker N55RF, registered to and operated by National Aircraft Leasing as a Part 91 business flight, landed gear up at Boeing Field (BFI) in Seattle. None of the three occupants was injured but the aircraft was substantially damaged during the landing on Runway 13R. N55RF was on an IFR flight plan operating in IMC, with the copilot in control of the aircraft.
The copilot reported that while preparing for landing on 13R, the captain asked her if she wanted 15 degrees of flaps and gear down. The copilot said she did. When the autopilot was disengaged, a loud “thumping” sound was heard and she called it to the captain’s attention. The captain stated that everything was normal and to continue flying. The captain called out and extended the flaps to 25 degrees, with the noise continuing. The copilot mentioned that “something did not feel right,” and the captain told her to continue.
The copilot glanced at the instruments and noticed that the landing gear was selected down and she saw three green lights. On short final, 45 degrees of flap was extended and the landing continued. No warning horns were noted. The copilot noted a “very long flare” and told the captain that something was wrong. At this time, the crew heard and felt the scraping sound and they then knew that the main landing gear was not down. After the aircraft came to rest, the copilot noted that the landing gear lever was in the down position.
The ATP-rated captain reported 13,497 hours TT, 1,713 hours of which were in the DH.125. The commercial-rated copilot reported 2,400 hours TT, with 200 of those in the DH.125. Both held a current second-class medical with no waivers or limitations.
A review of the cockpit voice recorder transcript indicates normal interaction between the copilot and captain during the approach until touchdown. At 1906:42, the cockpit area microphone picked up the sounds of scraping and rumbling.
At 1907:01, the captain stated, “Gear didn’t come down.” At 1907:25, the area microphone picked up the statement, “The gear didn’t come down. We put it down but it didn’t lock I guess. We didn’t see anything.” Following was, “We sure as hell got three reds now, but…” and “We had no warning and no warning horn…”
NTSB investigators had the aircraft placed on jacks after the accident and inspected the landing gear. Power was applied and the landing gear was cycled several times. All three landing gear extended and retracted with no anomalies noted. All three of the red and green gear indicator lights illuminated with the landing gear in the appropriate positions. The landing gear was retracted, the flaps were extended to 45 degrees and the power levers (left/right) were placed in the idle position. The investigator found that the “gear not extended” warning horn did not sound.
As a result of the investigator’s finding, the landing gear warning system was inspected by maintenance personnel from Galvin Flying Service. During the troubleshooting process, the mechanic found a bad set of contacts to the relay. Once the relay was jumped, the warning horn was confirmed. Maintenance records indicated that the last time the warning horn was functionally checked was in 1999.
The next scheduled functional test for this system was due four days after the incident. There is no push-to-test button for this system.