Attitude Instrument Flight with Helicopters[PDF]
- 1 Introduction
- 1.1 Instrument Cross-Check
- 1.2 Instrument Interpretation
- 1.3 Helicopter Control
- 2 See also
- 3 Reference
- 4 Author
Attitude instrument flying is the first part of the practical instrument flight training. In this part you will learn how to control a helicopter by reference to the instruments rather than by outside visual cues. When pilots lose visual references due to low visibility, the only remaining source which shows the current attitude of the helicopter are the on board instruments.
So much the more vital this is for helicopter pilots since they usually fly in visual flight conditions with less sophisticated avionics on board. In bad weather conditions, it is more likely for a helicopter pilot to enter inadvertent instrument meteorological conditions which basically means IFR flight without preparation.
In this case, a thorough ability of attitude instrument flying is the key to a successful transition of your flight from visual to instrument conditions.
- Instrument crosscheck
- Instrument interpretation
Cross-checking, often called scanning, is the continuous and logical observation of instruments for attitude and performance information.
Due to human error, instrument error and helicopter performance, which varies in different atmospheric and loading conditions, it is difficult to establish an attitude and have performance remain constant for a long period of time.
The flight instruments together give a picture of what is happening. To understand the helicopters current state in the most effective way, scanning these instruments in correct order is very important.
Controlling a helicopter is the result of accurately interpreting the flight instruments and translating these readings into correct control responses.
The pitch attitude of a helicopter is the angular relation of its longitudinal axis to the natural horizon.
- Attitude indicator
- Airspeed indicator
- Vertical Speed indicator.
The attitude indicator gives a direct indication of the pitch attitude of the helicopter. In instrument flight, attain the desired pitch attitude by using the cyclic stick to raise and lower the miniature aircraft in relation to the horizon bar.
The altimeter gives an indirect indication of the pitch attitude of the helicopter. A decreasing altitude is the indication of low pitch; an increasing altitude is the indication of high pitch.
Vertical Speed Indicator
The VSI gives an indirect indication of the pitch attitude of the helicopter and should be used in conjunction with the other pitch instruments to attain a high degree of accuracy and precision.
The airspeed indicator gives an indirect indication of helicopter pitch attitude. An increasing speed is the indication of low pitch, a decreasing speed is the indication of high pitch.
The bank attitude of a helicopter is the angular relation of its lateral axis to the natural horizon.
- Attitude indicator
- Heading indicator
- Turn indicator
The attitude indicator gives a direct indication of the bank attitude of the helicopter. Bank degree marks are placed on the upper periphery of the dial to assist pilots. The short degree marks on both sides of center are 10 degrees apart and the long degree marks are 30 degree apart.
If the helicopter is properly trimmed and the rotor tilts, a turn begins. The turn can be stopped by leveling the miniature aircraft with the horizon bar.
In coordinated flight, the heading indicator gives an indirect indication of a helicopter’s bank attitude.
A turn can also be detected on the heading indicator without any indication of bank on the attitude and turn indicator. This means that the helicopter is turning around its yaw axis.
Turn and Slip Indicator
During coordinated flight, the needle of the turn-and-slip indicator gives an indirect indication of the bank attitude of the helicopter.
- Manifold Pressure or
- Torque indicator, depending on the type of helicopter engine.
After interpreting the power instrument, collective control movements are made to attain required power setting to keep desired altitude/airspeed.
Trim refers to the use of pedal adjustment to centre the ball of the turn-and-slip indicator and the ball should always be kept centered through proper pedal trim.
All power changes directly increase or decrease anti-torque effect of the main rotor and this effect causes the ball of the turn-and-slip indicator to deviate left or right.
- Helicopter Instrument Straight-and-Level Flight
- Helicopter Instrument Straight Climbs
- Helicopter Instrument Straight Descents
- Helicopter Instrument Turns
- Helicopter Instrument Unusual Attitudes
- Helicopter Instrument Takeoff
- Instrument Flying Handbook (FAA-H-8083-15B)
- VID 522050- Creation
DATE OF SUBMISSION
- 12:49, 23 February 2021
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.