Aircraft: Cirrus SR22. Injuries: 1 Serious, 1 Minor. Location: Birmingham, Ala. Aircraft damage: Substantial.
What reportedly happened: The pilot was attempting to fly an ILS approach. Review of data revealed that the autopilot approach mode was armed as the airplane intercepted the localizer course and was descending to 2,600 feet MSL.
At that time, the autopilot was selected to vertical speed (VS) mode with the altitude armed rather than selected to the altitude mode, which is one of the criteria for automatically arming the glideslope (GS) mode later in the approach.
About one minute later, the autopilot automatically cancelled the VS mode and switched to altitude mode as the airplane reached 2,600 feet MSL.
However, at that time the airplane was above the glideslope by 53% needle deflection. The autopilot will not automatically arm the GS mode unless, in addition to the altitude mode being selected, the airplane is more than 10% needle deflection below the glideslope.
As a result, the airplane remained above the glideslope until the autopilot was disconnected about one minute later.
The pilot then attempted to hand-fly a missed approach, however, he was unable to maintain the heading or altitude assigned by air traffic control. He subsequently lost control of the airplane during a turn and elected to deploy the airplane’s parachute system. The airplane came to rest in a vacant lot.
Probable cause: The pilot’s failure to maintain control during a missed approach in instrument meteorological conditions. Contributing to the accident was the pilot’s overreliance on the autopilot system and his inability to hand-fly the airplane once the autopilot was disconnected.
NTSB Identification: ERA13LA012
This October 2012 accident report is are provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.