Gulfport, MS, USA
N8170J
BEECH 200
The airplane was on an instrument approach when the pilot attempted to extend the landing gear. During the gear extension process, the passengers heard a “loud bang” under the floor panels, and the pilot reported that the gear would not extend. The pilot diverted to another airport and attempted to extend the landing gear manually, which was unsuccessful as the landing gear system was jammed. The pilot landed with the gear retracted and the airplane sustained substantial damage to the fuselage and empennage. A postaccident examination of the landing gear revealed that the gear was still jammed and could not be actuated with the gear handle or by manual extension. The right landing gear drive shaft was unable to rotate and exhibited a binding during the rotation attempt. The examination and disassembly of the right main landing gear actuator revealed that the initial failure originated between the bevel gear set. The pinion gear and driven gear exhibited damage and fractures of their respective teeth. The cracked teeth and pitch line pitting present on the pinion gear indicate that it exhibited fatigue wear prior to the failure of the bevel gears. The final surface of the driven gear was significantly smeared, which obstructed the examination and analysis of the surfaces for fatigue-like cracks and wear patterns. Although the failure was within the bevel gear set, the initiating gear failure could not be determined due to the damage. The pinion gear had effective case depth but did not meet the drawing requirements for minimum case hardness. The driven gear did not show evidence of case hardening and did not meet the drawing requirements for both effective case depth and minimum case hardness. Since the bevel gear set were operational for more than 12,000 cycles, it is likely that the case hardness did not contribute to the gear failure.
On March 6, 2022, about 2130 central standard time, a Beech 200 airplane, N8170J, was substantially damaged when it was involved in an accident at Gulfport-Biloxi International Airport (GPT), Gulfport, Mississippi. The pilot and four passengers were not injured. The flight was operated as a Title 14 Code of Federal Regulations Part 91 business flight. The pilot reported that while on an instrument approach to Stennis International Airport (HAS), Bay St Louis, Mississippi, he attempted to extend the landing gear but it would not extend. He requested to hold while he attempted to manually extend the gear, but the manual extension handle was jammed. He diverted to GPT and again attempted to extend the landing gear without success, so he made a gear-up landing. According to the Federal Aviation Administration (FAA) inspectors, the airplane was on approach to HAS when the pilot attempted to extend the landing gear. During the gear extension process, the passengers heard a “loud bang” under the floor panels and the pilot reported that the gear would not extend. The pilot diverted to GPT and attempted to extend the landing gear manually, which was unsuccessful as the landing gear system was jammed. The pilot landed with the gear retracted and the airplane sustained substantial damage to the fuselage and empennage. After landing, there was a small fire under the right engine nacelle. Postaccident examination of the landing gear by the FAA revealed that the gear was still jammed and could not be actuated with the gear handle or by manual extension. They cut the landing gear drive shafts to the left and right gear actuators. The left drive shaft was successfully rotated using channel lock pliers. The right drive shaft would barely move and exhibited a binding sound and feel during the rotation attempt. The airplane was relocated to the recovery facility where the right main landing gear actuator was removed and shipped to the FAA aircraft certification office (ACO) in Wichita, Kansas. An examination and disassembly of the right main landing gear actuator was completed by Textron Aviation under the supervision of the FAA ACO. The examination concluded the following: 1. The initial component failure originated between the straight bevel gear set. 2. Breakage of the teeth from the pinion gear varied in fracture surface and location. The individual teeth that broke off have different features in comparison to the six adjacent teeth that were broken. a. The individual broken teeth show cracking features that would have developed progressively before failure. b. The group of adjacent broken teeth have evidence of shear overload and tensile overload, indicating the failure was abrupt and possibly related to shock overloading. c. Smearing that occurred during the final stages of mechanical failure obscures additional evidence to the failure modes present. 3. The broken pinion gear teeth exhibited internal secondary cracks. 4. The driven gear teeth were plastically deformed and cracked along the tip of the addendum as it smeared against the broken section of pinion teeth. Additional cracks were observed near the root of the driven gear but could not be confirmed as either a result of fatigue or overload cracking. 5. The appropriate grease was used and abundant within the housing. 6. Both the pinon and driven gears were confirmed to be the correct alloy per the drawing requirements. 7. The pinion gear had effective case hardening to the appropriate depth but did not meet the drawing requirements for minimum case hardness. 8. The driven gear did not have evidence of case hardening and did not meet the drawing requirements for both effective case depth and minimum case hardness. A review of the maintenance record revealed that on January 6, 2015, the right main landing gear actuator was overhauled and later reinstalled on the airplane. As of the accident date, the right main landing gear actuator was to be overhauled or replaced every 8,000 cycles, which was due in 7,429 cycles. On October 20, 2021, during a maintenance phase inspection, the main landing gear mechanical actuators were inspected per the aircraft maintenance manual with no defects noted. This inspection was completed at 12,449 total cycles. As of the accident date, the right main landing gear actuator was to be inspected every 1,000 cycles, which was due in 945 cycles.
The failure of the right main landing gear actuator, which led to a gear-up landing.
Source: NTSB Aviation Accident Database
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