TAKEOFF FLIGHT PATH PERORMANCE

1. TAKEOFF FLIGHT PATH PERORMANCE Obstacle Clearance Requirements

2. Takeoff Flight Path The takeoff flight path is considered to begin when the airplane has reached a height of 35� above the surface and continues to the higher of 1500� above the surface, or the point the single engine en-route climb speed is reached. Large aircraft have numerous takeoff configurations which affect departure path profiles. Each time a flap or slat selection is to be retracted an acceleration is required. An acceleration during climb with one engine inoperative results in a period of level flight.

3. Climb Gradients In an aircraft with multiple takeoff configurations and flap retraction schedules a climb gradient must be calculated taking into account each period of acceleration. Climb Gradient: the ratio of the change in height during a portion of a climb, to the horizontal distance traversed in the same time interval. The climb gradient required is predicated on one-engine inoperative performance and is expressed as a percentage. Alt. gained in feet/horizontal distance in feet�100=climb gradient Net Climb Gradient: the aircrafts actual one engine inoperative climb gradient reduced by 0.8%. This 0.8% reduction in actual climb gradient provides an additional safety margin for obstacle clearance. The aircrafts net climb gradient must meet the required climb gradient of the departure procedure and clear all obstacles by 200� horizontally or 35� vertically within the aerodrome boundary and 300� horizontally outside the aerodrome boundary. A standard � departure procedure would require a single engine net climb gradient of 200ft/nm or (200/6076)�100=3.3%

4. Climb Segments The takeoff flight path is divided into segments, which relate to aircraft configuration. A typical segmented profile is as follows: First Segment: from the end of the takeoff distance to the point the landing gear is fully retracted. (V2) Second Segment: the point the landing gear is retracted to an altitude of at least 400� (obstacle dependant). (V2) Third (Transition) Segment: the horizontal distance required to accelerate at a constant altitude to facilitate flap/slat retraction and acceleration to final climb speed. Final Segment: end of third segment to at least 1500� (obstacle dependant) with flaps/slats retracted, max. continuous power, and final climb speed.

6. Minimum Certification Performance For the aircraft certification process minimum performance requirements are specified in the CARS for each segment of climb. The aircraft must be capable of obtaining this minimum performance for all certified weight, altitude, temperature combinations. Only at the most adverse combinations of weight, altitude, and temperature will aircraft performance represent these minimums. Any conditions more favorable to performance will result in climb gradients better than the minimum.

7. Company Assessed Departures The standard � mile departure gradient is a generic obstacle clearance departure profile which works for most general aviation operations at most airports. Larger aircraft operating with higher takeoff weights and more stringent governing regulations commonly do not meet the required net gradient. Most operators hire companies who specialize in assessing airports for obstacle clearance requirements, to set up aircraft specific departure procedures which allow for less restrictive climb gradients. These departure procedures can be quite complex, involving a number of required gradients at different stages of the procedure, track changes, and aircraft bank restrictions.

10. Noise Abatement Procedures Noise abatement procedures have been developed for turbo-jet aircraft in the interest of avoiding disturbance to noise sensitive areas. The CAP will include procedures specific to the airport. There are two established procedures: A and B Procedure A results in noise relief during the latter part of the procedure. Procedure B results in noise relief close to the airport.

11. AIM RAC 7.6.3