TD 21

Question 1

Aerobatic Maneuvers

Answer 1

Aerobatic maneuvers are prohibited. Aerobatic flight is defined to be any intentional maneuver involving an abrupt change in aircraft attitude, an abnormal attitude, or pitch angle greater than 30 degrees or roll angle greater than 60 degrees, or abnormal acceleration not necessary for normal flight.

Question 2

Landing In Trees

Answer 2

A landing in trees should be made when no other landing area is available. In addition to accomplishing engine malfunction emergency procedures, select a landing area containing the least number of trees of minimum height. Autorotate with the throttle closed using the following procedures:
Airspeed - Minimum at treetop level
Descend - Vertically into trees
Collective - Apply remaining collective prior to blades entering trees.

Question 3

Hypoxia

Answer 3

Hypoxia is defined as the state of oxygen deficient in the blood cells and tissues significant enough to cause impairment of function.

Four Types
Hypoxic - reduction in pressure oxygen/PO2 encountered at high altitudes
Hypemic - reduction in the oxygen-carrying capacity of the blood
Histotoxic - reduction in the ability to transfer O2 from the blood to tissues
Stagnant - reduction in bloods ability to circulate properly in the body

Four Stages
(0-10k ft) Indifference 90-98% O2 saturation
(10-15k ft) Compensatory 80-89% O2 saturation
(15-20k ft) Disturbance 70-79% O2 saturation
(20k + ft) Critical 60-69% O2 saturation

Question 4

Hydraulic Power Failure

Answer 4

The first indication of hydraulic boost failure will be an increase in the force required for control movement, feedback forces will he noticed as well as rate limiting. Control motions will result in normal flight reactions in all respects, except for the increase in force required for control movements. In the event of hydraulic power failure proceed as follows:
Airspeed - Adjust as necessary to attain the most comfortable level of control movements.
HYD BOOST circuit breaker - Out. Check for restoration of hydraulic power

If hydraulic power is not restored.
HYD BOOST circuit breaker - In.
WARNING
Do not return the HYDR SYSTEM switch to the ON position for the remainder of the flight. This prevents any possibility of a surge in hydraulic pressure and the resulting loss of control.
HYDR SYSTEM switch - OFF
Land as soon as practicable at an area that will permits a run-on landing

Question 5

Chp. 8 Lightning Strike

Answer 5

WARNING
Avoid flight in or near thunderstorms, especially in areas of observed or anticipated lightning discharges
NOTE
Abnormal operating noises almost always accompany rotor damage, but loudness or pitch is not valid indications of the degree of damage sustained.

If lightning strike occurs, or is expected, the following precautions are recommended to minimize further risk.
Reduce airspeed as much as practical to maintain safe flight.
Avoid abrupt control inputs