This article provides guidance for controllers on what to expect and how to act when dealing with an aircraft experiencing engine failure while in controlled airspace. There are some considerations which will enable the controller, not only to provide as much support as possible to the aircraft concerned, but also maintain the safety of other aircraft in the vicinity and of the ATC service provision in general.
Useful to Know
As the nature of the engine failures is very diverse, this article is not envisioned to address all of them. The flight crew SOPs for single engine failure of multi-engine aircraft is very different from an engine failure of single engine aircraft. It is critical if the engine failure is contained or uncontained. The uncontained engine failure poses a greater risk since ejected debris from the engine could create hazard to the occupants and the structure of the aircraft and hence the risk of engine fire increases. Other risk scenarios associated with engine failure can range from an in-flight inadvertent thrust reverser deployment to an engine(s) flame-out due to the ingestion of volcanic ash.
The following technical problems could be precursors to engine malfunction and subsequent failure, and the crew might elect to shut down the problematic engine if there is:
- Low oil pressure indication
- High oil temperature indication
- Excessive engine vibrations
Another critical element to consider is the phase of flight in which the engine failure occurs. Depending on the phase of flight, the engine failure might result in:
Anticipated Impact on Crew
A wide range of practical problems could arise in the cockpit following an engine failure associated with:
- Heavy workload in the cockpit - the crew must assess the situation and the workload might become intense
- Announcing the problem - the crew will communicate the problem to ATC. Emergency communication protocols (MAYDAY or PAN PAN) should be used but non-standard phraseology (“We’ve lost No.2”, “Engine No.2 is gone/dead”, “We’ve got no thrust/power in No.2” etc.) often occurs.
- Seeking information and deciding on course of action - the crew will need any information available regarding adjacent aerodromes and weather conditions if the they elect to proceed to and land at the nearest suitable aerodrome
- Seeking optimal glide - in case of engine failure on single engine aircraft or multiple engine failure on multi-engine aircraft, the crew will seek the best glide ratio in order to attempt restart of the engine(s) and/or to reach next suitable aerodrome/airfield or place suitable for emergency landing.
What to Expect
- Deviation from SID - if the engine failure occurs at take-off or after rotation, the crew may follow an Emergency Turn routing and not follow the published SID and any associated noise abatement procedures
- Intermediate level-off - if the engine failure occurs during climb out or descent, the crew might elect to level-off the aircraft in order to assess the situation
- Descent - the crew may be forced to descend due to an inability to maintain altitude or might decide to descend (gain airspeed and re-start the engine) or to descend due to pressurisation problems connected with the engine failure
- Course deviation - the crew might decide to divert to the next suitable or to the alternate aerodrome
- Long and high speed approach and landing - due to performance limitations attributed to the engine failure the approach speed might be higher than prescribed, which could consequently may result in non-stabilised approach, runway excursion and blocked runway
- Slow turn rates - The turn rate is expected to be slow if it is executed on the inoperative engine side.
What to Provide
Best practice embedded in the ASSIST principle could be followed (A - Acknowledge; S - Separate, S - Silence; I - Inform, S - Support, T - Time):
A - acknowledge the problem (the declared malfunction and emergency if applicable), ask for the crews’ intentions when the situation permits.
S - separate the aircraft from other traffic and allow room to maneuver.
S - silence the non-urgent calls (as required) and use separate frequency where possible.
I - inform the adjacent ATC units if the aircraft is approaching or it is near their areas of responsibility; inform your supervisor and relay the flight crew’s intentions.
S- support the flight with any information requested and deemed necessary. Provide information and details about the next suitable aerodrome(s). If necessary inform the crew of the minimum safe altitude.
T - provide time for the crew to assess the situation, don’t press with non urgent matters.
The controller should be prepared to:
- Inform the crew about next suitable aerodrome and provide alternate aerodrome details and weather information as soon as possible
- Inform landing aerodrome of the inbound traffic with engine failure
- Clear RWY according to local instructions
- Keep safety strip clear
- Offer to the flight crew to fly an extended final approach
- Make sure go-around does not happen due to ATC reasons
- Ensure that towing equipment is on stand-by as appropriate
- Record last known position and time in case of forced landing
- Personal Awareness - ATCOs should always be monitoring the course and altitude of traffic in his/her sector. Being constantly aware of any ongoing deviations should provide precious time for vectoring of nearby traffic.
- Adequate Reaction - Some of the possible actions: transfer all other aircraft to another frequency (possible message to all stations to increase awareness); leave the emergency traffic on the current frequency; increase the volume of the receiver; have a colleague (a separate pair of ears) to also listen to all transmissions from the aircraft.
- Technological Limitations - Try to keep aircraft within radar cover. Have in mind the features of the existing radar system.
- Organisational Awareness - The appropriate provision of ATC service during emergency situations should be an objective at administrative level. Periodic training and drills are likely to improve intra-organisational coordination.