What happened
On March 9, 2007, a Beechcraft E55, registration PR-MJH, departed from Petrônio Portella Airport (SBTE) in Teresina, Brazil, bound for Gurguéia (SNGG) for a private transport flight. The aircraft was carrying one pilot and five passengers.
During the approach to Gurguéia, the pilot noticed that the left main landing gear failed to extend. After attempting to deploy the gear using both normal and emergency systems without success, the pilot contacted ground personnel via mobile phone, who confirmed the gear remained retracted. Due to the lack of emergency support at the destination, the pilot decided to return to Teresina.
Upon returning to SBTE, further attempts to extend the gear failed. The pilot performed a gear-up landing. During the landing roll, the left wingtip, propeller, and left flap made contact with the runway. The aircraft slid several meters before coming to a stop off the runway. All six occupants were unharmed, but the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the landing gear assembly and discovered that the left main landing gear retraction linkage had fractured in two locations. The investigation found no visible signs of corrosion, improper welding, or material fatigue on the component.
Investigators reviewed the aircraft's maintenance manual, which specifies precise procedures for adjusting the spring tension on the retraction linkage using a tensiometer to ensure a tension between 55 and 65 lbs. Interviews with maintenance personnel revealed that the standard practice in some maintenance facilities involved checking spring tension by hand rather than using the required specialized tools and following the manufacturer's specific procedures.
Findings
- The left main landing gear failed to extend due to the fracture of the retraction linkage.
- The fracture was likely caused by improper maintenance involving incorrect spring tension adjustment.
- Maintenance practices often bypassed the manufacturer's required use of a tensiometer, relying instead on manual tactile checks, which led to excessive load on the linkage.