January 21, 2011

National Transportation Safety Board — preliminary report

National Transportation Safety Board, www.ntsb.gov 14 January 2011

NTSB Identification: WPR11LA094
14 CFR Part 137: Agricultural
Accident occurred Monday, January 10, 2011 in Oakley, CA
Aircraft: ROCKWELL INTERNATIONAL S-2R, registration: N4977X
Injuries: 1 Fatal.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On January 10, 2011, at 1057 Pacific standard time, N4977X, a Rockwell International S-2R, impacted a meteorological tower (met tower) during an aerial application on Webb Tract Island, Oakley, California. The airplane sustained substantial damage and the pilot was killed. Alexander Ag Flying Service Incorporated was operating the airplane under the provisions of Title 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed and no flight plan was filed.

According to the Federal Aviation Administration inspector that responded to the accident site, the pilot had been applying seed when the accident occurred. Witnesses indicated that the pilot overflew the area and then began a pass over the field. Witnesses did not report seeing the airplane perform any evasive maneuvers prior to the impact.

According to a National Agricultural Aviation Association article on met towers, “Met testing towers are used for gathering wind data during the development and siting of wind energy conversion facilities. The met towers consist of galvanized tubing that are assembled at the site, and raised and supported using guy wires. Agricultural pilots, emergency medical services (EMS) operations, Fish and Wildlife, animal damage control, aerial fire suppression, and any other low-level flying operation may be affected. The fact that these towers are narrow, unmarked, and grey in color makes for a structure that is nearly invisible under some atmospheric conditions.”

The land owner indicated that the met tower on Webb Tract Island was erected in April 2009.

The project description stated that the tower stood 197 feet 8.25 inches tall and was designed specifically for wind resource measurements. Additionally, it stated “The 60-meter (197 feet) tower is lower than the 200 feet threshold set by the FAA, and as such meets FAA regulations.”

Title 14 CFR Part 77.13 “Construction or alteration requiring notice” states “(a) Except as provided in 77.15, each sponsor who proposes any of the following construction or alteration shall notify the Administrator in the form and manner prescribed in 77.17: (1) Any construction or alteration of more than 200 feet in height above the ground level at its site.”

URL to article:  https://www.wind-watch.org/news/2011/01/21/national-transportation-safety-board-preliminary-report/