T-34C OUT-OF-CONTROL FLIGHT
Zero Airspeed Departure
Description: The Zero Airspeed Departure demonstrates the departure from
controlled flight associated with an unusually high pitch attitude.
General: The maneuver will be entered by the Standardization Instructor and
recovered by the IUT. The aircraft will be positioned in a vertical attitude and power
will be reduced to idle. Airspeed will decrease to zero and upon departure, the nose
will fall forward or backward depending on the exact attitude at the top of the
maneuver. Minimum entry altitude for the Zero Airspeed Departure is 8000 feet
It is preferred the nose fall forward at the departure point due to the
aircraft going through fewer pitch oscillations (typically one) prior
to recovery. If the nose falls backwards, the aircraft typically goes
through 3 or more pitch oscillations before positive "G's" and
recovery are established. These oscillations neutralize the inverted
and upright pickups in the oil pump inlet, thereby causing a low
spike in oil pressure.
Perform the Stall Checklist and Clearing turn.
Add maximum allowable power and accelerate to aerobatic cruise
(approximately 180 - 190 KIAS).
Smoothly raise the nose to the vertical (3 1/2 "G" pullup recommended).
Reference the wingtip against the horizon.
Once vertical, reduce power to idle.
Hold back stick pressure to maintain a vertical attitude until the aircraft departs
Reverse airflow over the control surfaces will cause significant
feedback to the controls. Failure to maintain neutral controls can
result in damaged controls and control stops.
2-16 UNUSUAL ATTITUDES AND OUT-OF-CONTROL FLIGHT