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Engine Failures in Jets?


How do Airline Pilots deal with an engine failure in the most critical stages of takeoff?

Everyday thousands of flights depart every minute and Pilots are trained to be well prepared for a critical failure of the aircraft's most vital component, the engines! During pre-flight preparation, pilots will calculate the aircraft's performance data and one key speed is the V1 Critical speed. This V1 speed is a speed at which during the takeoff roll if an engine fails or malfunctions, pilots can decide wether they can safely reject the takeoff and stop the aircraft on the remaining runway available or the need to get airborne first before commencing a return to the airfield. Before V1 a pilot is mainly stop minded and as the aircraft accelerates and approached V1 which occurs just before rotation speed (VR), he/she is more go minded as due to reaction times it could prove dangerous to stop the aircraft on the remaining runway safely without overshooting into a bigger disaster!

So what happens when the engine fails close to or after V1?

The first thing that will occur is for the aircraft to yaw towards the failed engine side due to a power difference. Pilots will use the appropriate rudder pedal to neutralise this yaw effect and keep the nose of the aircraft straight. At this point if departing from a limiting airfield, pilots may even consider applying maximum available thrust on the remaining engine, for e.g. if terrain ahead was an issue! Once the aircraft reaches rotation speed, the pilot flying will slowly raise the nose up but to an angle suitable for single engine flight. This angle is lower than of course two engine operations. On achieving a safe climb, the gear is raised to reduce drag and increase climb performance. At this point it is very critical for the flying pilot to concentrate on the manual flight handling including trimming the rudder to reduce foot pressure on the rudder and for pilot monitoring to check all flight parameters are safe and within limits. It is for instance very easy to rotate the aircraft to normal angles due to every day operations, therefore risking the speed to trend towards stall speeds and this is where the role of the monitoring pilot plays a key role to announcing such abnormalities and allowing the flying pilot to timely correct such actions.

In the climb now with Gear Up.

Once safely climbing and the rudder has been trimmed, the pilots can activate the autopilot (if available) to reduce their workload further and concentrate on aviating. In some restricted terrain places, it could be highly important to commence a turn before reaching high terrain and so such actions also need to be taken care of in order to navigate the aircraft away from danger. Once all this has been done, the next priority is to start the abnormal engine failure checklists. There are a number of possible scenarios and these play a key role on the time available and the next decision pilots make. These include:

1. Engine has failed but no damage e.g. a stall! In this case perhaps once above the minimum safe altitude, pilots may consider restarting the engine. In this case again, the ideal option is to finish the attempts and checklists in the hold and consider returning back to the airfield or a nearby alternate.

2. Engine has failed with damage e.g. severe bird strike. In this case, restarting a damaged engine is NOT recommended and once all checks have been completed in securing the engine above the safe altitude, a return to the airfield is ideal or to an alternate nearby.

3. Engine Fire. In any fire or smoke cases, the immediate priority becomes to land as soon as possible. In aviation, if a fire cannot be extinguished within 15 minutes, it is unlikely that it will be and so a burning aircraft is an extremely high threat to a safe operation. A fire is always a RED alarm and so although the pilot monitoring will be running quickly through a checklist and trying to extinguish the fire using the equipped engine fire agents, there is no guarantee of this occurring and therefore it becomes a vital priority for the flying pilot to navigate in accordance to returning back quickly.

Pre-Flight Habits?

In every scenario, it shows the importance of doing a very good pre-flight briefing amongst the crew. It is not the ideal time during an emergency to be planning your actions and so briefing creates a pre-planned plan in the event of things going wrong. This is extremely useful especially in the fire case above. Both pilots will know what their planned actions need to be in this scenario and so this creates better time management, accurate checklist completion and correct navigation all together enhancing safety.

It is also important to practise good CRM during such abnormal cases. Keeping your cabin crew and passengers informed keeps everyone in the loop. Effective communication with ATC is also required with minimum conversation and details so as to have more time and capacity for flying and navigating. The flying also includes carrying out the necessary checks and securing of the engine or fire. This goes with the rule of aviation most known: Aviate, Navigate and Communicate. It might sound like 3 simple words but if correctly followed and prioritised in that order, you're assured to have the best and most safe outcome. This is why Pilots train so hard and re-practise such scenarios every six months in the simulator so as to preserve and contain such situations and safely land back where ample security and safety is readily available.

There is of course a lot more to what occurs during an abnormal flight scenario however this article gives you as a student pilot and enthusiast a brief highlight of what is expected in the real world. If this was a useful read please do share it with other like minded aviators out there.

Happy New Year to all.

FlightCopilot.

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