Chute happens: Pilot gets iced up
Chute happens: Pilot gets iced up
January can be a challenging month for flying. Even in southern states, pilots can encounter ice in flight. Lurking unseen in innocent-looking clouds, ice destroys the smooth flow of air, increasing drag while decreasing the ability of the airfoil to create lift. The airplane may stall at much higher speeds and lower angles of attack than normal. It can roll or pitch uncontrollably, and recovery may be impossible.
Case in point: On Jan. 13, 2006, a Cirrus SR22 had an in-flight loss of control while climbing in icing conditions in the vicinity of Childersburg, Ala. Fortunately, the pilot and two passengers survived the ordeal because, as they say, “chute happens.”
The IFR flight departed Birmingham International Airport en route to Orlando, Fla., at 3:44 p.m. Following departure, the airplane was identified by radar, and the pilot was instructed to climb to 7,000 feet. The aircraft entered the clouds at 5,000 feet on autopilot, climbing at 120 knots.
Upon reaching 7,000 feet, the airplane encountered icing conditions. The pilot requested and received approval to climb to 9,000 feet. However, as the airplane emerged from the cloud tops at 8,000 feet, it began to buffet. The pilot looked at his airspeed indicator, which read 80 knots. The airplane then stalled and began spinning to the left, reentering instrument flight conditions.
The pilot reduced power, neutralized the flight controls, and applied right rudder. Unable to break the spin, he deployed the aircraft’s ballistic parachute system and informed air traffic control of his actions. The airplane descended to the ground under the parachute canopy, collided with trees, and came to rest about four feet above the ground. The aircraft received substantial damage, but the pilot and two passengers reported no injuries.
On the night before the accident, the 12,700-hour, ATP-certificated pilot obtained a full DUAT briefing. The briefing was not valid for the time of the accident. Before noon on the day of his flight, the pilot requested an abbreviated DUAT weather briefing for his route. The in-flight advisories were to expire at 3 p.m.—nearly an hour before his departure time.
The pilot stated he was not aware of airmet Zulu update 3, which was issued an hour before he departed Birmingham and was broadcast over the XM Satellite Weather service available in the airplane. The airmet warned of occasional moderate mixed icing in clouds between 3,000 and 8,000 feet.
The NTSB determined that the probable cause of the accident was the pilot’s inadequate preflight planning, failure to obtain a current weather briefing, and his decision to operate the airplane into a known area of icing outside the aircraft’s certification standards.
Because most light aircraft are not approved for flight in known icing conditions, it is critical for pilots to consult the most recent weather information—especially when planning a flight through a cloud layer in winter months. It’s also wise to avoid using the autopilot in potential icing conditions. An autopilot can mask the aerodynamic effects of the ice and may fly the aircraft into a stall. Lastly, remember to request pireps—and give some of your own—along your route if you suspect icing to be a potential problem.
November 11, 2009