LAX06LA109

The airplane collided with obstacles and terrain during a forced landing following a loss of engine power. Between 400 and 500 feet above ground level (agl) during the takeoff climb, the engine lost power, started again, and then lost power again. The airplane made an emergency landing on a roadway and the left wing clipped the median. An initial examination of the engine revealed no anomalies that would have precluded normal operation except that both of the magnetos did not spark at any post when manually rotated. A second examination of the magnetos occurred at the manufacturer's facilities. They mounted the magnetos to a test stand. The magnetos produced a blue spark across a 7 mm gap through the full range of test bench rpm.

On February 12, 2006, about 1205 mountain standard time, a SIAI-Marchetti S.205/22R, N981WA, experienced a loss of engine power in the takeoff initial climb and collided with obstacles and terrain near Phoenix, Arizona. A private individual was operating the airplane under the provisions of 14 CFR Part 91. The pilot and one passenger sustained minor injuries, and one passenger was not injured. The airplane sustained substantial damage. The local personal flight departed Phoenix Deer Valley Airport about 1203. Visual meteorological conditions prevailed, and no flight plan had been filed. The approximate global positioning system (GPS) coordinates of the primary wreckage were 33 degrees 45 minutes north latitude and 112 degrees 0 minutes west longitude.

Between 400 and 500 feet above ground level (agl) during the takeoff climb, the engine quit, started again, and then quit again. The left wing clipped the median during an emergency landing on a roadway.

The engine was a Franklin 6A-350-C1, serial number 5520-3.

Investigators examined the wreckage at Air Transport, Phoenix, Arizona, on April 25, 2006, under the supervision of the Federal Aviation Administration (FAA).

Investigators removed the engine. They slung it from a hoist, and removed the top spark plugs. All spark plugs were clean with no mechanical deformation. The spark plug electrodes were elliptical and gray, which corresponded to normal operation according to the Champion Aviation Check-A-Plug AV-27 Chart.

A borescope inspection revealed no mechanical deformation on the valves, cylinder walls, or internal cylinder head.

Investigators manually rotated the crankshaft with the propeller. The crankshaft rotated freely, and the valves moved approximately the same amount of lift in firing order. The gears in the accessory case turned freely. Investigators obtained thumb compression on all cylinders in firing order.

Investigators manually rotated the magnetos, and neither magneto produced spark at any post.

The National Transportation Safety Board investigator-in-charge (IIC) sent the magnetos to Teledyne Continental Motors (TCM).

TCM personnel examined the magnetos under the supervision of the IIC at the factory in Mobile, Alabama, on March 2, 2007.

The left-hand magneto was intact and undamaged. The drive gear was secure, and the teeth were undamaged. The magneto shaft turned freely by hand, and the impulse coupling engaged. The distributor block, contact points, and condenser were intact and undamaged; their analyst indicated that they exhibited normal operating signatures. The analyst installed the magneto on a test bench, and it produced a blue spark across a 7 mm gap through the full range of test bench rpm.

The right-hand magneto was intact and undamaged. The drive gear was secure, and the teeth were undamaged. The magneto shaft turned freely by hand. The distributor block, contact points, and condenser were intact and undamaged. The contact point gap was below the minimum specification. The analyst installed the magneto on a test bench, and it produced a blue spark across a 7 mm gap through the full range of test bench rpm.