Transport category aircraft are certificated under Title 14 of the CFR (14 CFR) parts 25 and 29. The airworthiness certification standards of parts 25 and 29 require proven levels of performance and guarantee safety margins for these aircraft, regardless of the specific operating regulations under which they are employed.

10.9.1 Major Differences in Transport Category Versus Non-Transport Category Performance Requirements #

• Full temperature accountability—all of the performance charts for the transport category aircraft require that takeoff and climb performance be computed with the full effects of temperature considered.
• Climb performance expressed as percent gradient of climb—the transport category aircraft’s climb performance is expressed as a percent gradient of climb rather than a figure calculated in fpm of climb. This percent gradient of climb is a much more practical expression of performance since it is the aircraft’s angle of climb that is critical in an obstacle clearance situation.
• Change in lift-off technique—lift-off technique in transport category aircraft allows the reaching of V2 (takeoff safety speed) after the aircraft is airborne. This is possible because of the excellent acceleration and reliability characteristics of the engines on these aircraft and due to the larger surplus of power.
• Performance requirements applicable to all segments of aviation—all aircraft certificated by the FAA in the transport category, whatever the size, must be operated in accordance with the same performance criteria. This applies to both commercial and non-commercial operations.

10.9.2 Performance Requirements #

The performance requirements that the transport category aircraft must meet are — Takeoff: takeoff speeds; takeoff runway required; takeoff climb required; obstacle clearance requirements. Landing: landing speeds; landing runway required; landing climb required.

10.9.3 Takeoff Planning #

Listed below are the speeds that affect the transport category aircraft’s takeoff performance. The flight crew must be thoroughly familiar with each of these speeds and how they are used in takeoff planning.

• VS—stalling speed or the minimum steady flight speed at which the aircraft is controllable.
• VMCG—minimum control speed on the ground, with one engine inoperative (critical engine on two-engine airplanes), takeoff power on other engine(s), using aerodynamic controls only for directional control (must be less than V1).
• VMCA—minimum control speed in the air, with one engine inoperative (critical engine on two-engine aircraft), operating engine(s) at takeoff power, maximum of 5° bank into the good engine(s).
• V1—critical engine failure speed or decision speed. Engine failure below this speed shall result in an aborted takeoff; above this speed the takeoff run should be continued.
• VR—speed at which the rotation of the aircraft is initiated to takeoff attitude. The speed cannot be less than V1 or less than 1.05 times VMC. With an engine failure, it must also allow for the acceleration to V2 at the 35-foot height at the end of the runway.
• VLOF—lift-off speed. The speed at which the aircraft first becomes airborne.
• V2—the takeoff safety speed which must be attained at the 35-foot height at the end of the required runway distance. This is essentially the best one-engine operative angle of climb speed for the aircraft and should be held until clearing obstacles after takeoff, or until at least 400 feet above the ground.
• VFS—final segment climb speed, which is based upon one-engine inoperative climb, clean configuration, and maximum continuous power setting.

All of the V speeds should be considered during every takeoff. The V1, VR, V2, and VFS speeds should be visibly posted in the flight deck for reference during the takeoff.

Takeoff speeds vary with aircraft weight. Before takeoff speeds can be computed, the pilot must first determine the maximum allowable takeoff weight. The three items that can limit takeoff weight are runway requirements, takeoff climb requirements, and obstacle clearance requirements.

10.9.4 Runway Requirements #

The runway requirements for takeoff are affected by: pressure altitude; temperature; headwind component; runway gradient or slope; and aircraft weight.

The runway required for takeoff must be based upon the possible loss of an engine at the most critical point, which is at V1 (decision speed). By regulation, the aircraft’s takeoff weight has to accommodate the longest of three distances: 1. Accelerate-go distance—the distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1 and continue the takeoff on the remaining engine(s). The runway required includes the distance required to climb to 35 feet by which time V2 speed must be attained. 2. Accelerate-stop distance—the distance required to accelerate to V1 with all engines at takeoff power, experience an engine failure at V1, and abort the takeoff and bring the aircraft to a stop using braking action.

3. Takeoff distance—the distance required to complete an all-engines operative takeoff to the 35-foot height. It must be at least 15 percent less than the distance required for a one-engine inoperative takeoff. This distance is not normally a limiting factor as it is usually less than the one-engine inoperative takeoff distance.

10.9.5 Balanced Field Length #

In most cases, the pilot will be working with a performance chart for takeoff runway required, which will give “balanced field length” information. This means that the distance shown for the takeoff will include both the accelerate-go and accelerate-stop distances.

The chart in Figure 10-35 shows the runway distance required under normal conditions and is useful as a quick reference chart for the standard takeoff. The V speeds for the various weights and conditions are also shown.

For other than normal takeoff conditions, such as with engine anti-ice, anti-skid brakes inoperative, or extremes in temperature or runway slope, the pilot should consult the appropriate takeoff performance charts in the performance section of the AFM.

There are other occasions of very high weight and temperature where the runway requirement may be dictated by the maximum brake kinetic energy limits that affect the aircraft’s ability to stop. Under these conditions, the accelerate-stop distance may be greater than the accelerate-go. The procedure to bring performance back to a balanced field takeoff condition is to limit the V1 speed so that it does not exceed the maximum brake kinetic energy speed (sometimes called VBE). This procedure also results in a reduction in allowable takeoff weight.