Incident Overview
On January 28, 2013, the National Transportation Safety Board was notified that a Beech King Air C90, registration N14CP, had sustained substantial damage to the left wing at an undetermined time and location. The aircraft was operated under an exclusive contract between Dynamic Aviation and the Bureau of Land Management (BLM) as a public aircraft from April 2, 2012, to October 21, 2012. During a post-contract inspection on January 21, 2013, the damage was discovered. No injuries were reported during the contract period.
Contract Operations
The aircraft was under an exclusive-use contract primarily for BLM fire management activities, including low-level lead airplane and air attack missions. BLM provided pilots and crew, while Dynamic Aviation supplied the airplane and maintenance personnel. Over the contract term, the aircraft flew 318 total hours across 113 flights. BLM pilots flew 110 flights, and a relief BLM pilot flew 3 flights totaling 5.2 hours.
Damage Discovery and Progression
Around May 10, 2012, government pilots and the contract mechanic first observed deformation and wrinkles on the left wing outboard of the nacelle. The mechanic inspected the area and, after consulting with company supervisors, decided to monitor it for further damage. No entries were made in the maintenance logbooks. On August 15, 2012, a BLM pilot reported encountering moderate turbulence and requested a turbulent air inspection. The relief mechanic reported finding nothing. When the primary mechanic returned, he noted the wrinkle appeared slightly worse, but no further action was taken. The aircraft continued flying until October 31, 2012.
Post-Contract Inspection
On November 9, 2012, the aircraft was flown from Boise, Idaho, to Redmond, California, and returned to Dynamic Aviation's control. On December 10, 2012, maintenance personnel discovered the left wing damage, noting it had progressed since previous observations. Photographs and descriptions were sent to the Hawker Beechcraft repair design office for assessment. The assessment concluded that the damage was consistent with conditions known to exist when the wing assembly has experienced loading in excess of normal operating limits. Determining that the left outer wing assembly required replacement with a new or serviceable assembly.
Investigation and Findings
The Department of the Interior Office of Aviation Services conducted a mishap investigation and submitted a report on May 17, 2013. The investigation determined that the contractor held the required FAR 135 certificate, and the contracted aircraft was properly certificated for the contract. However, the aircraft was not listed on the contractor's FAR 135 certificate, nor was it required under the contract. The Department of the Interior now mandates that contracted aircraft be included on the contractor's FAR 135 certificate and/or in the Operations Specifications. Additionally, the Department now requires load monitoring equipment on various aircraft to monitor dynamic loads during low-level flight operations.