Critical Engine Failure Speed

APPENDIX A

INTERMEDIATE FLIGHT PREPARATION WORKBOOK

Critical Engine Failure Speed

Critical Engine Failure Speed (VCEF) is defined as the speed at which one engine can fail and the

same distance is required to either continue to accelerate to lift-off speed, or to abort and

decelerate to a full stop.

Critical Field Length

The Critical Field Length (CFL) is the total length of runway required to accelerate on all engines

to VCEF, experience an engine failure, then continue to liftoff or stop. It is used during takeoff

planning, together with the climbout data, to determine maximum gross weight for a safe takeoff

and climbout. For a safe takeoff the critical field length must be no greater than the runway

available.

Takeoff Factor

Takeoff Factors (TOF) are used to simplify the use of charts. These TOF numbers are %N1

settings adjusted for Outside Air Temperature (OAT) and altitude and are presented on a

different scale. The TOFs are used to enter various charts which require a thrust correction.

Takeoff Ground Run

Takeoff ground run distance is defined as that runway distance normally obtained in service

operation at zero wind at the mission-specified weight, pressure altitude, thrust setting, ambient

temperature, and appropriate takeoff configuration, using lift-off speed. The runway shall have

no slope.

Minimum Control Speed Ground

Minimum Control Speed Ground (VMCG) is the speed (88 KIAS) during the takeoff run, at which,

when an engine is failed, it is possible to maintain directional control using only primary

aerodynamic controls without deviating more than 25 feet laterally. This speed is established

with the remaining engine at the takeoff thrust setting, with the aircraft loaded at the most

unfavorable weight and center of gravity, with the aircraft trimmed for takeoff, and without

exceeding 180 pounds of rudder control force. Conditions of crosswind and RCR may increase

VMCG.

Minimum Control Speed Air

Minimum Control Speed Air (VMCA) is the minimum in-flight speed (89 KIAS) at which an

engine loss can be experienced and directional control maintained using full rudder deflection, 5

AOB into the operating engine, and not more than 180 lbs of rudder control force. VMCA is

always less than takeoff speed and is not considered in takeoff planning.

A-4 GLOSSARY