WPR23LA154

The pilot reported that, on the downwind leg, the green landing gear indicator lights did not illuminate when he extended the gear. He then went through the emergency landing gear extension checklist and noted that the landing gear pump handle had high resistance, indicating to him that the landing gear was down. He felt excessive drag and suspected that the main landing gear doors were open. The pilot stated that he conducted a low pass over the runway and made a radio call requesting visual confirmation of the gear being down and locked, but no response was received. The pilot reported that flaring the airplane during the landing was very difficult due to the open gear doors and the nose gear and left main landing gear collapsed on touchdown. Automatic dependent surveillance - broadcast (ADS-B) data showed the airplane making a normal crosswind turn and then angling toward the runway threshold before making a tight left base turn to the final leg of the pattern. The airplane landed hard, short, and to the right of the runway threshold. The left main landing gear and the nose landing gear collapsed due to the hard landing, and the left wing sustained substantial damage. A postaccident examination of the landing gear system revealed that all three landing gear were in the down and locked position when the airplane touched down. Further examination revealed that the left landing gear limit switch was not functioning properly, rendering it unable to sequence the door solenoid valve to the door close position. This resulted in the main landing gear doors remaining open, causing excessive drag. The pilot's execution of an overly tight base turn, likely exceeding the critical angle of attack, and the increased drag caused by the open main landing gear doors, likely led to the pilot not properly flaring the airplane, which resulted in a hard landing.

On April 16, 2023, at 0930 Pacific daylight time, a Cessna 337, N38C, was substantially damaged when it was involved in an accident near Upland, California. The pilot and a passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Cable Airport, (CCB), Upland, California for a local flight. When he returned to CCB, on the downwind leg, he lowered the landing gear handle and the landing gear indicator lights did not illuminate with a three green indication. He performed the emergency landing gear extension checklist and noted the landing gear pump handle had high resistance, which indicated to him that the gear was down. He also felt excessive drag and suspected the main gear doors were open. During the interview with the pilot, he mentioned that he experienced anxiety at that moment while referring to a recent fatal accident involving an airplane of the same model. The pilot considered the possibility that this accident potentially occurred due to the main landing gear doors remaining open, which could have caused excessive drag. He conducted a low pass over the runway and made a radio call asking if anyone could verify whether the landing gear was down and locked, but there was no response. The pilot reported flaring the airplane during the landing was very difficult due to the open gear doors, and the nose gear and left main landing gear collapsed on touchdown. Automatic dependent surveillance - broadcast (ADS-B) data showed the airplane made a normal crosswind turn and then angled towards the runway threshold before making a tight left base turn to final. The airplane landed hard, short, and to the right of the runway threshold. The left main landing gear and the nose gear collapsed and the left wing sustained substantial damage. Both main gear doors were found in the open position. Figure 1: The accident airplane’s final approach path A postaccident examination was conducted on the landing gear system. The landing gear remained in the same position as when the accident occurred. Both the nose and left main landing gears had separated but the extension mechanisms were in the down and locked position. The right main landing gear was in the down and locked position and undamaged. Both main landing gear doors were open. The hydraulic reservoir was full of hydraulic fluid. The landing gear was cycled multiple times through gear extension and retraction to test each landing gear. During the examination the main landing gear doors failed to close properly. To close the main landing gear doors all three limit switches must be operational, allowing the door solenoid valve to move the doors to the closed position. While individually testing each limit switch through visual inspection and isolating them one by one, all components operated as expected, except for the left limit switch, which was identified as worn and defective.