Autopilots Are Not Automatic
The importance of understanding how to operate avionics
I
BY J. MAC MCCLELLAN
TAKEOFF INTO LOW CLOUDS or visibility demands careful planning and
a thorough check to be sure all avionics and systems are set properly.
The pilot of a Cirrus SR22 appeared to have done just that before
departing into a 300-foot overcast at Cuyahoga County Airport in
Cleveland, Ohio, bound for Buffalo, New York. But shortly after liftoff everything went wrong.
The instrument-rated private pilot had logged more than 1,300
hours’ total time. He reported 400 hours of instrument flight experience and had completed a transition course into the Cirrus. The
pilot’s logbooks were not available to the NTSB, so it could not
determine how many hours he had logged in the SR22 he had purchased about eight months before the accident.
The pilot had flown the Cirrus from his home base at Buffalo just
a few hours before the accident flight. Weather conditions for his
arrival were similar to the low clouds and light rain that were over
the airport for departure.
The SR22 was equipped with a flat-glass primary flight display
(PFD) and multifunction display (MFD) that were linked to the
autopilot. The avionics system included a recorder that noted airplane flight tracking, including attitude, altitude, airspeed, vertical
speed, and also recorded selected autopilot modes.
The pilot’s clearance was to fly the Runway 6 heading up to 3,000
feet. Before takeoff the pilot set the 3,000-foot altitude assignment
into the altitude “bug” window. He also selected runway heading on
the heading bug and entered a target vertical speed of 850 fpm. That
is exactly the standard procedure that should be used for any IFR
takeoff, particularly one into low clouds or low visibility.
The avionics system also had a flight director that could show the
pilot what pitch and bank attitude to maintain to satisfy the heading and
climb targets he had entered into the system. Or the autopilot could be
engaged and it would fly the airplane to the preselected targets.
This pilot clearly had confidence in his
avionics/autopilot system, or perhaps not a
great deal of confidence in his instrument
flying abilities, because just five seconds
after the flight-tracking data recorded liftoff
he engaged the autopilot at an altitude of 61
feet above the runway. The tower controller
reported that the takeoff and initial climb
looked normal, but the Cirrus was quickly
out of sight in the overcast.
The pilot initially engaged the autopilot
in heading hold mode so the system would
maintain the runway heading selected by the
heading bug on the PFD. One second later
the pilot engaged the autopilot vertical
speed mode.
Pressing the vertical speed mode button
on the autopilot control panel causes the
autopilot to capture and attempt to maintain
whatever vertical speed is set in the so-
called “bug” window. Pressing the altitude
button on the autopilot causes the system to
capture the present altitude, whatever it
may be. Pressing both the altitude mode and
vertical speed mode buttons at the same
time will “arm” the altitude hold mode so
the autopilot will automatically capture the
target altitude set in the altitude “bug.”
For whatever reason, just one-half sec-
ond after the pilot engaged vertical speed
mode the autopilot went into altitude hold
