
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.
The SR22, by Cirrus
Design, is a high-performance single-engine, four-seat, composite aircraft. It is a more powerful
version of the Cirrus SR20, with a larger wing, higher fuel capacity,
and a 310 horsepower (231 kW) engine. It is extremely popular among purchasers
of new aircraft and has been the world's best-selling single-engine, four-seat
aircraft for several years [1]. Like the Cessna 400,
but unlike most other high-performance aircraft, the SR22 has fixed
(non-retractable) landing gear.
The plane is perhaps best
known for being equipped with the Cirrus Aircraft Parachute System (CAPS),
an emergency parachute capable of lowering the entire aircraft (and occupants)
to the ground in an emergency.