What happened
On 12 February 2021, a Piper PA-44-180, registration G-BGCO, was performing a routine private flight near Warton Airfield when the pilot encountered a landing gear malfunction. While attempting to land, the pilot selected the landing gear to the down position; however, while the main gear indicated they were locked, the nose landing gear displayed an unsafe indication.
The pilot attempted several recovery procedures, including recycling the gear selection, replacing indicator bulbs, and using varying g-loads to encourage the gear to lock. Despite visual confirmation via an engine cowling mirror and an external check by the ATC tower suggesting the gear was down, the cockpit indication remained unsafe. After consulting with a factory test pilot, the pilot elected to divert to Blackpool Airport to access better maintenance support. Upon landing on Runway 10, the nose landing gear collapsed, causing the aircraft to come to rest on its nose. The pilot escaped the aircraft without injury, but the aircraft sustained no injuries to the crew while suffering damage to both engines, both propellers, and the nose gear, rendering it damaged beyond economic repair.
The investigation
Following the accident, the aircraft was moved to maintenance facilities at Blackpool. During testing on jacks, investigators found that the nose gear would only lower correctly when connected to a ground electrical supply, failing to operate properly on battery power alone. Furthermore, the emergency gravity-and-spring-assist system failed to move the nose gear from its raised position.
Maintenance personnel noted that extreme force was required to manually pull the nosewheel down. During this process, it was discovered that the pivot bolt connecting the upper and lower landing gear drag link assemblies was impossible to remove. The operator also noted that there had been prior instances of similar issues involving the distortion or failure of this specific bolt.
Findings
- The nose landing gear failed to lock in the down position during the approach to Warton.
- The collapse of the nose gear upon touchdown was the primary cause of the damage to the engines and propellers.
- Distortion or failure of the pivot bolt in the nose landing gear assembly likely prevented the gear from locking and restricted its movement.