What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On 10/26/2021 at approximately 1441 EDT, the crew of N5852K declared an emergency for a landing gear malfunction and the aircraft safely landed at Battle Creek airport (btl). The incident follows the occurrence dated 10/19/2021 (OGL0920210066) with similar information regarding an unscheduled landing required because of landing gear/hydraulic issues.
The maintenance facility determined the original issue to be a faulty hydraulic dump valve and subsequently replaced it, which was later determined to be an incorrect diagnosis. On this flight, the crew experienced a malfunction with the hydraulic landing gear and returned to the airport. The maintenance facility performed troubleshooting and found that their technician had induced the fault by performing a procedure to clean the pneumatic lines that was not specified in the aircraft maintenance manual. The unauthorized procedure shifted the shuttle valves and caused the landing gear fault. It was determined the technician performed the faulty procedure twice, prior to the occurrence and prior to the incident.
As a precautionary maintenance action, both landing gear shuttle valves for the hydraulic system were replaced with overhauled components and the aircraft returned to service.
The maintenance facility has filed a report under the voluntary disclosure reporting program.
As the FAA filed it
ON 10/26/2021 AT APPROXIMATELY 1441 EDT, THE CREW OF N5852K DECLARED AN EMERGENCY FOR A LANDING GEAR MALFUNCTION AND THE AIRCRAFT SAFELY LANDED AT BATTLE CREEK AIRPORT (BTL). THE INCIDENT FOLLOWS THE OCCURRENCE DATED 10/19/2021 (OGL0920210066) WITH SIMILAR INFORMATION REGARDING AN UNSCHEDULED LANDING REQUIRED BECAUSE OF LANDING GEAR/HYDRAULIC ISSUES.
THE MAINTENANCE FACILITY DETERMINED THE ORIGINAL ISSUE TO BE A FAULTY HYDRAULIC DUMP VALVE AND SUBSEQUENTLY REPLACED IT, WHICH WAS LATER DETERMINED TO BE AN INCORRECT DIAGNOSIS. ON THIS FLIGHT, THE CREW EXPERIENCED A MALFUNCTION WITH THE HYDRAULIC LANDING GEAR AND RETURNED TO THE AIRPORT. THE MAINTENANCE FACILITY PERFORMED TROUBLESHOOTING AND FOUND THAT THEIR TECHNICIAN HAD INDUCED THE FAULT BY PERFORMING A PROCEDURE TO CLEAN THE PNEUMATIC LINES THAT WAS NOT SPECIFIED IN THE AIRCRAFT MAINTENANCE MANUAL. THE UNAUTHORIZED PROCEDURE SHIFTED THE SHUTTLE VALVES AND CAUSED THE LANDING GEAR FAULT. IT WAS DETERMINED THE TECHNICIAN PERFORMED THE FAULTY PROCEDURE TWICE, PRIOR TO THE OCCURRENCE AND PRIOR TO THE INCIDENT.
AS A PRECAUTIONARY MAINTENANCE ACTION, BOTH LANDING GEAR SHUTTLE VALVES FOR THE HYDRAULIC SYSTEM WERE REPLACED WITH OVERHAULED COMPONENTS AND THE AIRCRAFT RETURNED TO SERVICE.
THE MAINTENANCE FACILITY HAS FILED A REPORT UNDER THE VOLUNTARY DISCLOSURE REPORTING PROGRAM.