Landing With Wind Gradient or Wind Shear

APPENDIX H

INTERMEDIATE FLIGHT PREPARATION WORKBOOK

EADI of approximately 3 nose low. Descend at a rate required for the penetration being

performed. At approximately 1000 feet above level off altitude, reduce drag as necessary in

preparation for level-off.

Rapid

Idle power, speed brakes extended. Above 24,800 feet, establish IMN of 0.78. Below 24,800

feet, establish IAS of 330 KIAS.

Non-Standard Temperature

Time to descend and fuel to descend increase at temperatures below ISA, and decrease at

temperatures above ISA. For every 10 C below ISA increase time and fuel to descend by 3.5%.

For every 10 C above ISA, decrease time and fuel to descend by 1.5%. The affects of

temperatures on distance to descend are negligible.

Anti-Ice Systems

When descending with anti-ice, time and distance to descend may increase by as much as 50%

and fuel consumed may increase by as much as 350% depending on ice accumulation. Maintain

approximately 70% N2 when descending with anti-ice systems on.

H106. LANDING WITH WIND GRADIENT OR WIND SHEAR

Wind velocity is generally higher a short distance above the runway than it is on the runway

itself. Entering this wind gradient during the landing approach could result in a change in

airspeed which requires correction.

When landing with a headwind, more thrust is required to maintain a desired glidepath than is

necessary with no wind. Also, the decreasing magnitude of the headwind in the gradient can

cause a decrease in airspeed, which has to be counteracted with the use of additional thrust to

prevent a possible short landing. With a tailwind during the landing approach, the proper

glideslope is maintained with a lower thrust setting and since the magnitude of the tailwind is

decreasing during penetration of the wind gradient, airspeed may have a tendency to increase,

requiring a reduction in thrust. If these corrective measures are not taken, there is a possibility of

overshooting the runway, necessitating a go-around.

The effect of crosswind will also be considered during the landing approach. As the aircraft

approaches the runway, less correction for crosswind may be required to maintain the proper

flightpath.

The degree of corrective action necessary during an approach is dependent upon the severity of

the wind gradient. With a sharp gradient, the change in airspeed could be very rapid, requiring

an immediate correction. The combination of wind gradient, plus wind that is intermittent or

variable in direction and/or speed, requires caution always be exercised during the landing

H-8 T-1A PERFORMANCE MANUAL EXTRACTS