Ground Resonance; Inadvertent Overspeeding Above Maximum Limit Speed; Inadvertent Slowing Down Below Minimum Limit Speed - Kazan Helicopters Mi-17-1V Flight Manual

MI1-17-1B. Flight manual
6.14. Ground resonance
(1) Indications
(a) Occurrence of rapidly increasing oscillations of the helicopter during
the engine ground test, taxiing, landing run or takeoff.
(2) Crew's actions
(a) Upon occurrence of rapidly increasing oscillations of the helicopter
in the course of the engine ground test, vigorously push the collec-
tive pitch control lever down and simultaneously turn the throttle
control twist grip fully to the left.
(b) Upon occurrence of increasing oscillations during landing run, take-
off and taxiing reduce the helicopter forward speed by pulling back
the control stick (to a position close to neutral) and apply the LG
wheel brakes.
If the helicopter oscillations persist shut down the engines in any
condition stated above.
6.15. Inadvertent overspeeding above maximum limit speed
(1) Inadvertent overspeedinq above the maximum limit speed may cause
stalling of the main rotor blades accompanied by increased vibration, de-
teriorated controllability and rocking of the helicopter.
In this case smoothly reduce the main rotor collective pitch and simulta-
neously pull back the control stick to reduce the airspeed down to a de-
sired level.
6.16. Inadvertent slowing down below minimum limit speed
(1) Indications
(a) Occurrence of the helicopter vibration similar to that occurring dur-
ing pre-landing deceleration.
(b) Helicopter turning and nose heaviness.
(c) Inadvertent loss of altitude at various vertical speeds depending on
the initial power setting with the collective pitch control lever posi-
tion unchanged.
(d) Unsteady readings of the airspeed indicator (oscillation of the
pointer within the range of 50 to 350 km/h).
(e) Oscillation of the engine tachometer indicator pointers within ±2
%
with the collective pitch control lever fixed.
(2) Crew's actions for recovery from inadvertent slowing down below the
minimum limit speed are as follows:
(a) If the helicopter attains a speed below the minimum limit at power
settings corresponding to horizontal flight or climb proceed as fol-
1) With the engine power unchanged, smoothly push the control
stick forward to establish a pitch angle within the limits of -(.5
to 10)° and initiate acceleration of .the helicopter.
2) On reaching a forward speed of 80 to 100 km/h establish the
horizontal flight condition and a desired speed.
(b) If the helicopter is slowed down below the minimum limit speed in
glide proceed as follows:
6-20