Page 37 - April 2017 Twin & Turbine

get hung up on the verbiage. Unless developed by the local airport, though, ATC will not know the specifics of the procedure, but they will understand your intent and clear traffic when necessary. Even so, once airborne is not the time to wing it and pull a procedural rabbit-out-of-your-engine-failure hat.
Planning for the failure before takeoff is required. After an engine failure, high terrain, man-made obstacles, the airport elevation, aircraft performance or any combination of these factors may make it impossible to meet the climb gradient described in a SID or an ODP, whereas EOSIDs are based on specific aircraft performance in case of an engine failure. It’s the responsibility of the operator to recognize this performance deficit and to develop engine-out takeoff procedures when and where required. In such cases, EOSIDs should have sufficient guidance, both to avoid obstructions and so that they can be followed in IMC and VMC.
The Nitty Gritty
Pilots departing an airport under IFR and operating under Part 121 or 135 are required by the FAR’s to use an OEI procedure that assures compliance with obstacle clearance requirements.
According to Advisory Circular 120-91:
“The methods and guidelines presented in this AC are neither mandatory nor the only acceptable methods for ensuring compliance with the regulatory sections. Operators may use other methods if those methods are shown to provide the necessary level of safety and are acceptable to the FAA.”
OEI procedures developed by Part 121 and 135 operators follow these guidelines and are then “accepted” by their company’s FAA POI (Principal Operations Inspector). Airport and runway analysis involves complex, usually computerized computations of aircraft performance and the use of extensive obstacle databases and terrain information. Methods of complying include either using a contract company to create avoidance procedures or developing your own. Most Part 121 operators have performance engineers on staff to conduct runway analysis and produce Emergency Turn data for their company. Part 135 operators often use third-party vendors to generate the desired information. And, in some cases, EOSIDs are published by individual airports.
The most widely used OEI planning method compares a climb gradient published on a SID or ODP with the OEI climb gradient from the Aircraft Flight Manual (AFM); usually the second segment OEI climb gradient. The maximum allowable bank angle below 400 feet AGL is typically 15 degrees and any maneuvers should guide the aircraft around or away from terrain using this bank angle constraint.
Other considerations in planning include ground based navaid and
GPS tolerances, obstacle clearance during straight takeoff and turns, wind effect during turns and loss of climb performance during turns. Any procedures must also be designed to ensure that the third segment climb (level acceleration/flap retraction) can be completed and thrust reduced to maximum continuous (MCT) before the time limit for takeoff thrust. Ultimately, the path of the EOSID should lead to a point at which the aircraft can plan a landing or continue to the destination or an alternate.
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