Refusal Speed

INTERMEDIATE FLIGHT PREPARATION WORKBOOK

APPENDIX A

Refusal Speed

Refusal Speed (VR) is the maximum speed that can be attained with normal acceleration from

which a stop may be completed within the available runway length. VR is compared with VMCG

and VROT in determining S1.

Maximum Braking Speed

Maximum Braking Speed (VB) is the maximum speed from which the aircraft can be brought to a

stop without exceeding the maximum brake energy limit (14.8 million ft-lbs total). When setting

up the Takeoff Acceleration Check, care should be taken to choose the checkpoint such that the

resulting speed is below VB.

Takeoff Acceleration Check

A Takeoff Acceleration Check provides a speed for a given distance during takeoff ground roll.

This speed can be checked against aircraft IAS at that distance point to ensure the takeoff is

proceeding normally. Takeoff Acceleration Check speed should be adjusted to be at least 10

KIAS less than S1. Compute Takeoff Acceleration Check whenever S1 is less than VROT.

Go/No-Go Speed

The takeoff is committed at IASs above Go/No-Go Speed (S1). If an engine failure occurs prior

to obtaining S1, takeoff abort capability is assured. In takeoff planning, S1 is equal to or greater

than the higher of VMCG or VCEF. However S1 must not be higher than the lowest of VR, VROT, or

VB. If it is higher, the takeoff weight must be reduced until this requirement is met.

Rotation Speed

Rotation Speed (VROT) is defined as the speed at which the aircraft attitude is increased from the

ground run (taxi) attitude to the lift-off attitude. This speed is greater than the VMCG.

Lift-Off

Lift-off is the moment at which the main gear lifts off the runway.

Lift-Off Speed

Lift-Off Speed (VLOF) is the speed at which lift-off occurs.

Takeoff Flare

Takeoff flare is the ground distance covered between lift-off and the 50-foot obstacle height.

GLOSSARY

A-5