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of the helicopter in relation to the natural horizon. During instrument flight, follow ex actly the sam e procedu re in raising or lowering the miniature aircraft in relation to the horizon bar. 

There is some delay between control application and resultant instrument change. This is the normal control lag in the helicopter and should not be confused with instrument lag. The attitude indicator may show small misrepresentations of pitch attitude during maneuvers involving acceleration, deceleration, or turns. This precession error can be detected quickly by cross-checking the other pitch instruments. 

If the miniature aircraft is properly adjusted on the ground, it may not require readjustment in flight. If the miniature aircra ft is not on the horizon bar after level off at normal cruising airspeed, adjust it as necessary while maintaining level flig ht with the other pitch instruments. Once the miniature aircraft has been adjusted in level flight at normal cruising airspeed, leave it unchanged so it gives an accurate picture of pitch attitude at all times. 

When making initial pitch attitude corrections to maintai n altitude, the changes of attitude should be small and smoothl y applied. The initial movement of the horizon bar should n ot exceed one bar width high or low. [Figure 8-3]  If a fur ther adjustment is required, an additional correction of one - half bar normally corrects any deviation from the desired altitude. This one-and-one-half bar correction is normally the maximum pitch attitude correction from level flight attitude. 

After making the correction, cross-check the other pitch instruments to determine whether the pitch attitude change is sufficient. If additional correction is needed to return to altitude, or if the airspeed varies more than 10 knots from that desired, adjust the power. 

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## Altimeter 

The altimeter gives an indirect indi cation of the pitch attitude of the helicopter in straight-and-level flight. Since the altitude should remain constant in level flight, deviation from the desired altitude indicates a need for a change in pitch attitude and power as necessary. When losing altitude, raise the pitch attitude and adjust power as necessary. When gaining altitude, lower the pitch attitude and adjust power as necessary. Indications for power changes are explained in the next paragraph. 

The rate at which the altimeter moves helps to determine pitch attitude. A very slow movement of the altimeter indicates 

