Engine Failure-Flight Planning Altitude Selection
Updated: Aug 26, 2022
Engine failure at any point in flight will have a huge increase in workload and stress well flying. Its important to note that flying is very safe however as a pilot you must always be ready for the worst-case scenario. Generally when training you will get an engine failure at the worst time possible during takeoff or before landing. Having a way to process to manage the Engine Failure is the most important part of dealing with an Engine Failure.
During an Engine failure its most important to Fly, Navigate and Communicate. Most aircraft will have the ability to perform OEI (one engine inoperative) given the fact it is a twin aircraft and must be able to fly net OEI climb gradients that can be seen in the Performance and Loading exam and linked to this blog. During the failure its important to fly and trim the aircraft in the correct state and phase for flight. If in cruise you will be required to descend to a new flight level as performance on one engine is not sufficient to maintain the current level.
OEI flight levels can be seen in the blue book on page 5.2 as seen below:
These flight levels are dependent on the Gross Weight at the time or either TOC (SZW) for the cruise and the temperature. The higher the temperature the lower the flight level, similar to weight the heavier the weight the lower the altitude you can fly. The gross weight is rounded to the nearest 1T and the temperature is rounding to the nearest 5 degrees. For example 3 degrees would be rounded to 5 degrees and you would have to interpolate between ISA and ISA+10. The weight must be rounded to the nearest 1 tone and you must interpolate to get to that weight, for example an aircraft with a gross weight of 63,300kg you must round to 63T and then interpolate 60-65T and work out the flight level for 63T. This is an issue that many people have and the error they will make during the flight planning stage of study.
The temperature to use depends on the situation of the question. If in the cruise you must use the current RWST where the failure takes place, If doing a OEI climb then you must follow the climb wind/temperature rule of using FL185 at or below FL310.
During a OEI go-around or climb you must remember to add the allowance for OEI to the climb time, fuel and distance figures you get from the climb charts. When given then BRW to work out the OEI as a general rule you subtract 3T off the BRW( Brakes Release Weight) to get the TOC weight to use for TOC weight with OEI.
If you are looking for more help or tips for any ATPL then please contact through the website to have a free chat about flying, aviation or theory help. Check out this Blog on Flight level Allocation that will help you with OEI and normal flight level selection.