How an Aircraft Handles an Engine Failure During Flight

Imagine the worst-case scenario: one engine on an airplane fails during flight. Will the aircraft lose altitude? The answer is unequivocally 'Yes,' but let's explore the details.

Understanding the Concept of Altitude Loss

Upon an engine failure, an airplane will lose altitude due to the inherent reliance on the remaining engines for propulsion. Without power to maintain altitude, the plane will descend under controlled descent called a 'glide.'

Engine Failure Scenarios

Several factors determine whether the engine can be restarted:

Engine Integrity: An engine that has suffered a catastrophic failure and disintegrated cannot be restarted. Volcanic Ash Incident: A notable incident involved a Boeing 747 that flew into a volcanic ash cloud. The ash eroded the compressors, causing all four engines to flame out. Despite this seemingly catastrophic event, the crew managed to restart three engines after descending to a lower altitude, resulting in a successful landing. Cause of Engine Failure: Whether the engine failure is mechanical or operational, it can significantly impact the ability to restart. Modern turbofan engines are highly reliable when properly maintained, with a vastly lower failure rate compared to piston engines.

Optimizing the Descent

If an engine fails above the 'one engine out cruising altitude,' the aircraft usually descends to that altitude to maintain fuel efficiency. The descent is gradual rather than a free fall.

Procedures and Strategies

Key strategic decisions are made based on the situation:

Drift Down: If the engine fails at a high altitude, the aircraft may drift down to an altitude where the remaining engines can maintain power. This is a controlled process. Flight Management Computer (FMC): Many modern airliners have an FMC that provides information for a controlled descent. The pilot can select maximum continuous power on the remaining engines and adjust pitch to the speed dictated by the FMC.

At this point, the aircraft may lose a few hundred feet per minute, but it is not a free fall. The descent is carefully managed to ensure safety.

Engine Restart Procedures and Safety Considerations

During the descent, the crew will follow standard procedures as outlined by the engine manufacturer. These procedures address the conditions under which an engine can be restarted in flight:

Engine Damage and Restart: If there is damage, the crew may attempt to restart the engine, depending on the severity. Modern turbofan engines are designed with multiple layers of protection to prevent catastrophic failure.

Flight planning always considers the worst-case scenarios. Equipment and procedures are designed to ensure a safe landing at a suitable airport, regardless of the number of operational engines post-failure.

Conclusion

In summary, while an engine failure will result in a descent, modern aircraft are equipped with advanced systems to manage this situation effectively. The importance of proper maintenance, modern engine design, and crew training cannot be overstated in ensuring safe and controlled flight operations.