History of Flight
On July 20, 2013, at 2003 eastern daylight time, a Cirrus SR22, registration N223SS, was substantially damaged after impacting trees and terrain following the pilot's deployment of the airframe parachute. The private pilot and three passengers were not injured. The flight departed Salisbury-Ocean City Wicomico Regional Airport (SBY), Maryland, around 1930, destined for Hanover County Municipal Airport (OFP), Virginia. Visual meteorological conditions prevailed, and an instrument flight rules flight plan was filed.
The pilot reported hearing a loud noise from the engine while in cruise flight at 6,000 feet about 4 miles from Tappahannock-Essex County Airport (XSA), followed by a loss of engine power. He established best glide speed and declared an emergency with air traffic control, receiving vectors toward XSA. Approaching the airport, another loud noise was heard, and the windscreen became covered with oil. The pilot noted reduced glide capability and worsening visibility. At about 1,000 feet, he deployed the Cirrus Airframe Parachute System (CAPS), which successfully deployed. The airplane descended under canopy and came to rest among trees. The occupants egressed and were met by first responders.
Aircraft and Damage
The airplane was a 2006 Cirrus SR22 powered by a Continental IO-550-N 310-horsepower engine. The most recent annual inspection was on March 4, 2013, at 1,598 total hours. At the time of the accident, the airframe and engine had 1,664.3 hours. Examination revealed substantial damage to both wings. The engine cowling was removed, and oil was found throughout the compartment. The oil dipstick indicated 3 quarts remaining. The #2 connecting rod had breached the crankcase, and the rod, piston pin, and crankcase pieces were found on top of the engine.
Engine Examination
The engine was examined at the manufacturer's facility. Cylinders showed normal operating signatures and combustion deposits. The crankshaft and counterweight assembly were mechanically damaged. The #2 connecting rod was fractured at the base of the I-beam, with fragments exhibiting overload signatures. The crankcase had exterior damage concentrated at the #2 cylinder, with portions missing above it. Oil galleys and passages were intact and unrestricted. A material analysis of a fractured counterweight pin indicated overload failure.
Service Bulletin
On September 25, 2009, the engine manufacturer issued critical service bulletin CSB09-11, Minimum Cruise RPM Limits, for the accident engine make and model. It described two instances of sudden engine stoppage from crankshaft counterweight release, associated with sustained cruise rpm below 2,300 rpm. The manufacturer recommended cruise rpm settings no lower than 2,300 rpm. Review of recorded flight data showed 9 local flights in the 6 months prior where the accident airplane operated at or below 2,300 rpm for 20 minutes or longer.
Flight Data
Recorded data from the PFD and MFD showed takeoff at 19:28:00, climb to 8,000 feet pressure altitude, and cruise with fuel flow about 13 gph. At 19:59:46, engine rpm and EGT dropped to zero; oil pressure dropped from 40 to 33 psi. The aircraft then experienced increasing lateral oscillation. At 20:02:00, the waypoint changed to XSA. At 20:03:41 at about 500 feet, the aircraft pitched nose-down and rolled right, consistent with CAPS deployment. At 20:03:49, accelerations spiked, consistent with impact.