Air India Delhi-Mumbai Flight Incident: What Happens If Plane's Engine Fails Mid-Air? | Explained

Last Updated:December 24, 2025, 15:18 IST

An estimated 5-10 aircraft experience at least one engine shutdown every day and in 90% of these instances, passengers are not even aware that anything unusual has occurred

Aircraft engines contain thousands of components like blades, bearings, shafts and gearboxes. (Representative Image)

On December 22, an Air India flight operating from Delhi to Mumbai suffered a mid-air engine failure, forcing the aircraft to return to the national capital as a precaution. While the phrase “engine failure" can sound alarming, such incidents are neither unprecedented nor necessarily dangerous. Aircraft engines can and do shut down mid-air, yet in the overwhelming majority of cases, no tragedy follows because the aircraft is landed safely.

Globally, an estimated 5-10 aircraft experience at least one engine shutdown every day. In more than 90% of these instances, passengers are not even aware that anything unusual has occurred. Nearly 99% of the time, the aircraft lands without incident. With around 1,00,000 to 1,10,000 commercial flights operating worldwide every day, and most of them flown by twin-engine aircraft, modern aviation is designed to anticipate engine failures and handle them safely.

What is the most common cause of engine failure?

The most frequent trigger is a bird strike, particularly during take-off or landing when aircraft operate at lower altitudes. If a large bird enters the engine, sensors immediately detect abnormal conditions. The system then shuts the engine down automatically. This is not a failure in the conventional sense, but a safety response designed to prevent further damage.

Can an engine shut down because the aircraft runs out of fuel?

While theoretically possible, this is extremely unlikely. Fuel levels are verified multiple times before departure, by pilots, ground engineers and automated systems. Historical cases exist, such as the 1983 Gimli Glider incident, where a unit conversion error led to fuel exhaustion mid-air. Modern digital monitoring and cross-check systems have virtually eliminated this risk.

Under what conditions does engine pressure drop to zero?

Pilots typically refer to three different pressure-related scenarios. Zero oil pressure is the most critical, as oil lubricates the engine’s moving parts; without it, an engine can seize within minutes. Oil leaks or ruptured pipes can cause such a situation. A third possibility is oil pump failure due to mechanical issues. Even then, backup systems are designed to provide pilots with time to act.

Can mechanical parts inside an engine suddenly fail?

Yes, but such failures are rare. Aircraft engines contain thousands of components like blades, bearings, shafts and gearboxes. Each part has a defined service life and must be replaced after a fixed number of flight hours or cycles. Despite rigorous checks, aviation engineering accepts that zero risk is impossible, only minimised.

Do engines ever shut down without a fault?

Yes. Modern engines are designed to protect themselves. If sensors detect excessive temperature, abnormal vibration or falling oil pressure, the system may trigger an auto-protective shutdown. Technically, this is considered a safety feature rather than a malfunction.

Can weather cause engine failure?

Certain weather conditions can pose risks. Severe hail can damage engine inlets and blades. Heavy rain has, in older engine models, caused flameouts. Volcanic ash is the most dangerous threat, as it can melt inside engines and cause permanent damage. This was the reason large parts of European airspace were shut down after the 2010 Icelandic volcanic eruption.

Can maintenance errors lead to engine failure?

There is a possibility, though it is rare in today’s highly regulated environment. Errors may arise from improper installation, overlooked maintenance steps or manufacturing defects. When such incidents occur, inspections of similar engines are carried out worldwide, and aircraft may be grounded if required.

What do pilots do first if an engine fails mid-air?

Pilots are extensively trained for this scenario. Their immediate priority is to maintain full control of the aircraft. They follow standard operating procedures (SOPs), use autopilot if required, consult a written checklist, attempt an engine restart and divert to the nearest suitable airport.

Can a plane fly on just one engine?

Yes. This is one of the cornerstones of modern aviation safety. Most commercial jets are certified to fly, climb and land safely on a single engine. Regulations also ensure that aircraft on long routes can always reach a suitable diversion airport within a specified time.

What are the chances of both engines failing at the same time?

The risk is extremely low. Dual engine failure can occur only under exceptional circumstances such as a large flock of birds entering both engines, severe volcanic ash exposure or heavily contaminated fuel. Pilots are trained specifically for this rare scenario.

Do passengers usually realise that an engine has failed?

In most cases, no. The aircraft often continues to fly normally, and the shutdown may only be communicated after landing at an alternate airport. Many passengers remain unaware throughout the flight.

If both engines fail, does the aircraft immediately crash?

No. Even without engine power, an aircraft can glide. At cruising altitude, a commercial jet can cover 100 to 120 kilometres and remain airborne for 15 to 20 minutes. During this time, pilots attempt engine restarts and plan a landing at the nearest safe location; first an airport, then a military airstrip, and if necessary, water.

Does the aircraft lose all power if both engines stop?

No. Aircraft are equipped with backup systems, including a small wind-powered turbine that deploys automatically to supply essential electrical power and hydraulic control. This ensures pilots retain control of critical instruments.

Why is air travel still considered so safe?

Because aviation is built around a single guiding question – what if something goes wrong? Every critical system has redundancies, every emergency has a checklist, and pilots undergo regular simulator training for worst-case scenarios. That is why engine failures make headlines, but rarely end in accidents.

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