EOSID Requirements

For aircraft operating above 5700 kg and in accordance with CASA CAO 20.7.1B, operators must comply with paragraph 14 of the order for the development of takeoff performance data and procedures. Sub-paragraph 14.2, states:

“ Procedures to be followed consistent with this Order, including procedures anticipating engine failure at any time between the commencement of take-off and completion of landing, must be specified in the Operator’s Operation Manual. The procedures so specified must be such that they can be consistently executed in service by flight crews of average skill and they must also be such that the take-off flight path with all engines operating is above the one-engine inoperative take-off flight path.”

The takeoff flight path in the context of this guidance and for the purpose of defining the path requirements for an EOSID is as noted below:

The EOSID by definition must commence from a time where engine failure has occurred and where the flight crew are committed to a continued takeoff with one engine out. The takeoff flight path of the EOSID should be able to join a suitable en route path to the planned destination or to another suitable airport or at least have a holding pattern at the end of the EOSID.

The aircraft is considered to be enroute when it is at the higher attitude of 1500 feet:

CAO 20.7.1b Para 12.6

”The net flight path in the en-route configurations must have a positive slope at 1500 feet above the aerodrome where a landing is assumed to be made following engine failure. …”

or the altitude where 1000 feet enroute obstacle occurs

CAO 20.7.1b Para 12.4

“…the en-route obstacle clearance requirements are met if the en-route configuration with a critical engine inoperative the net flight path of an aircraft under V.M.C. clears by 1 000 feet vertically all obstacles within 5 nautical miles of the aeroplane’s track or, under I.M.C., by such greater distance as is determined by the accuracy of the navigation aid(s) used. “

Operationally alternative options are normally considered. This may include climbing to either a minimum safe altitude (MSA), a minimum vectoring altitude (MVA), or a fix and altitude, from which an approach may be initiated to the departure airport or departure alternate. Operators should note that the end of the takeoff flight path is determined by the aircraft’s gross flight path but the obstacle analysis must use the net flight path data.

The takeoff path extends from a standing start to a point, at which the aircraft is at a height of 1500 ft above the takeoff surface, or at which the transition from the takeoff to the en-route configuration is completed and the final takeoff speed is reached, whichever point is higher.

JAR/ FAR 25.111 Takeoff path.

“The takeoff path extends from a standing start to a point in the takeoff at which the airplane is 1,500 feet above the takeoff surface, or at which the transition from the takeoff to the en route configuration is completed and V FTO is reached whichever point is higher.”

CASA accepts the certification of aircraft as detailed in the Aircraft Flight Manual (AFM), however the operational rules of CAO 20.7.1B must be considered in the analysis. If there is any conflict between the AFM data and the operating rules, then if the AFM is more restrictive, that is what must be used. The takeoff path definition assumes that the aircraft is accelerated on the ground to VEF, at which point the critical engine is made inoperative and remains inoperative for the rest of the takeoff. Moreover, the V2 speed must be reached by 35 feet 1 above the takeoff surface (this point is also known as reference zero).

The aircraft must continue at a speed not less than V2 and achieve the regulatory climb and any obstacle clearance requirements until the aircraft reaches the acceleration altitude. The minimum height is 400 feet above the takeoff surface; however operators may select a higher altitude.

This path is a certification requirement and the certification standard is accepted by CASA. The related performance data is contained in the Aircraft Flight Manual (AFM).

Most of the time, runways have surrounding obstacles which should be taken into account prior to takeoff, to ascertain that the aircraft is able to clear them. A vertical margin has to be considered between the aircraft and each obstacle in the takeoff flight path. This margin, based on a climb gradient reduction, leads to the definitions of the Gross Takeoff Flight Path and the Net takeoff flight Path.

Gross Flight Path = Takeoff flight path actually flown by the aircraft, based upon the gross height attained. The flight path commences at reference zero.

Net Flight Path = Gross takeoff flight path minus a mandatory reduction, based upon the net height attained.

The gradient reduction is considered to account for pilot technique, degraded aircraft performance, and ambient conditions. The net takeoff flight path data must be determined so that they represent the actual (Gross) takeoff flight path reduced at each point by a gradient equal to:

0.8% for two-engine aircraft

0.9% for three-engine aircraft

1.0% for four-engine aircraft

CAO 20.7.1B Para 7.5

“In determining the net flight path of an aeroplane to show compliance with subsection 12, the gross gradients of climb achieved in paragraphs 7.2 and 7.4 must be reduced by 0.8% for twin-engined aeroplanes, 0.9% for three-engined aeroplanes and 1.0% for four-engined aeroplanes.”

The takeoff flight path can be divided into several segments. Each segment is characteristic of a distinct change in configuration, thrust, and speed. Moreover, the configuration, weight, and thrust of the aircraft must correspond to the most critical condition prevailing in the segment. Finally, the flight path must be based on the aircraft’s performance without ground effect. As a general rule, the aircraft is considered to be out of the ground effect, when it reaches a height equal to its wing span.

After an engine failure at VEF, whatever the operational conditions, the aircraft must fulfill minimum climb gradients, as required by the aircraft flight manual and the operational requirements of CAO 20.7.1B.

Figure above, summarizes the different requirements and aircraft configuration during the four takeoff segments. This includes the minimum required climb gradient with an engine out, flaps / slats configuration, engine power rating, speed reference, and landing gear configuration.

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Source:

CAAP 235-4(0): Engine Out SID (EOSID) and Engine Out Missed Approach Procedures