How Fast Do Airliners Fly?

How Fast Do Commercial Airliners Fly?

Just how quickly do passenger aircraft fly?

How fast do commercial passenger jets fly?

Commercial passenger jet aircraft cruise at about 400 – 500 knots (460 – 575 mph / 740 – 930 kph) – read more to understand the background behind it. However, this can only be achieved at high altitude, which is one of the reasons why commercial aircraft fly so high.

Speed can get a bit confusing when talking about an object moving through the air. You have a few types of speed; airspeed (and there a quite a lot of variations of airspeed) and ground speed.

Ground speed is self explanatory, it’s the time it takes you to cover a certain distance over the ground. When at their cruise altitude, aeroplanes might have a ground speed anywhere between 300 – 600 nautical miles per hour. Whilst they usually cruise at the same airspeed, the wind can make a big difference to the speed at which the aircraft passes over the ground. A tailwind pushes the aircraft along whilst a headwind slows the aircraft down. When a strong tailwind occurs, such as when crossing the Atlantic from West to East, the aircraft’s ground speed might reach exceed over 700mph.

Airspeed

Airspeed has a few different variations. If an aircraft is sat still on the runway and has a 20 mph headwind, the aircraft already has an airspeed of 20 mph, despite the fact it isn’t actually moving. This is because airspeed is a measure of the speed of the air over the wing. The speed of the air travelling over the wing dictates how much lift the wing is producing, and it’s this lift that allows the aircraft to support its own weight and allows it to fly.

If an aircraft has a take off speed of 140 mph, but has a 20 mph headwind, the aircraft will only need to achieve a 120 mph ground speed before it is able to take off. Conversely, if an aircraft has a 20 mph tail wind, it would need to achieve a 160 mph ground speed in order to lift off the ground.

Pilots always make reference their airspeed rather than ground speed as it is the airspeed that keeps the aircraft flying. The groundspeed is a byproduct. In principle, if you had about a 140 mph headwind the aircraft could lift off the ground without moving forward!

The Speed of Sound

When aircraft get to between 25,000 – 30,000 ft, they reference their speed to a “Mach Number”. This is simply a percentage of the speed of sound. For example, a Mach Number of 0.80 is 80% of the speed of sound. This is not a fixed speed, as the speed of sound varies with the temperature of the air.

The speed of sound at sea level with an air temperature of 15 degrees celsius is 761 Miles Per Hours. This reduces to about 660 miles an hour at -57 degrees celsius when at 36,000ft.

When aircraft approach the speed of sound, shockwaves start to form which causes aerodynamic issues. Aircraft therefore have a maximum mach number they can fly at, which is why this becomes the reference speed.

How Much Does Jet Fuel Cost?

The Price of Jet Fuel and Fuelling an Aircraft

A look at the cost of aviation fuel for commercial aircraft

How Much Does Jet Fuel Cost?

As of January 2021, the price of Jet A1 was approximately  $450 per metric tonne. With a metric tonne being 1,000 KG or 2,204 lbs, this equates to about $0.45 / £0.33 per KG.

This price is about 34% lower than one year ago (January 2020) where the price of Jet A1 was approximately $650 per metric tonne or about $0.65 per KG.

Due to collapse in oil price bought about by the Covid-19 pandemic, at one point (May 2020), Jet A1 was as low as $200 per metric tonne which equates to around $0.20 per KG.

Note:

1 KG (kilograms) = 2.2 LBS (pounds)

1 MT (metric tonne) = 1,000 KGS

Source: IATA

The price of jet fuel (known as Jet A1) is closely aligned the price of oil which varies on a daily basis. In May 2020, the price of Jet A1 was down 69% compared to the previous 12 months.

Example Calculations

The price of jet fuel as of January 2015 is as follows:

  • 170.8 Cents (US dollars) per Gallon
  • 1 litre = 0.3125 pence (pound sterling)
  • 1 litre = 0.40 Euros

It should be noted that it does not include the delivery of the fuel or the fee to actually refuel the aircraft. Therefore the price airlines actually pay for the fuel per kilogram will be higher than the figures outlined above, subject to the contract details. At present there is no tax on aviation fuel in Europe.

A Jumbo Jet (Boeing 747-400) flying from London to New York burns approximately 70,000 kilograms of fuel. As jet fuel has an approximate specific gravity of 0.85 (the measure of its density), this therefore equates to 82,300 litres.

Based on these figures, the cost of the fuel required to fly from London to New York being operated by a B747 Jumbo Jet is approximately £25,500 (€32,500), which based on 450 passengers, would work out at £57 (€73) per person.

Fuel Price Hedging

The prices airlines actually pay for their fuel varies substantially depending on what price they’ve “hedged” the fuel at. Hedging is where you agree a constant price for fuel for a set period of time into the future. This helps an airline to reduce risk and fixed costs which can be important for financial planning. For example, a fixed amount of fuel, lets say 5 million tonnes, might be hedged at $600 per metric tonne for 12 months. The airline will pay $600 per metric tonne regardless of any fluctuation in price of fuel during this time. If the fuel price goes up, the airline is protected from this rise whilst if there is a drop in fuel price, the airline will be paying more for fuel than it might have done.

The hedging is normally based on purchasing a set quantity of fuel. If the airline stops flying, such as due to the COVID-19 crisis and don’t use the fuel they’ve hedged, the airlines still have to pay for the fuel they hedged even if they don’t use it which can result in financial loses.

What Could Cause a Double Engine Failure?

Why Would Both Engines Fail On A Commercial Passenger Jet?

A look at the reasons that a passenger aircraft’s engines might fail . . .

What could cause a double engine failure?

Any engine failure is a very rare occurrence, and a double engine failure extremely improbable. But is has happened. Here are some of the factors which have caused double engine failures in the past.

Bird Strike

Birds can be very hazardous to aircraft. Flying through a flock of geese caused both engines to fail on US Airways Flight 1549 in 2009 that subsequently landed in the Hudson river in New York. A similar incident occurred in 2008 when Ryanair flight 4102 suffered around 90 individual bird strikes when flying through a flock of starlings on final approach into Rome Ciampino airport. Despite losing both the 737’s engines, the crew managed to land the aircraft on the runway. The aircraft was written off. There is a little a pilot can do to avoid birds other than try to manoeuvre the aircraft around them, but they often seen to late to attempt this.

Shutting down the wrong engine

It sounds difficult to believe, but it has happened. When there has been a problem with an engine, there have been examples of the crew shutting down the wrong engine as a result, leaving both engines failed. It’s not actually that difficult to do, especially when factoring in all the stresses and information sources. A famous example of this was the British Midland Flight 92 crash at Kegworth where 47 people died. Airlines have updated their procedures as a result and the engine shutdown process is now carefully monitored by both pilots.

Fuel Starvation

A fuel leak, or running out of fuel will cause both engines to fail. Air Transat 236 ran out of fuel due to a leak approximately 65 miles from the Azores in 2001. The pilots successfully managed to glide the aircraft to an airbase on the island. In 1983 Air Canda Flight 143 also ran out of fuel when descending through 35,000 feet, due to a fuel miscalculation (the weight of the fuel was measure in pounds instead of kilograms). The pilots successfully managed to glide the aircraft to safety onto a closed runway.

Fuel Icing

Icing in the fuel tanks could stop the engines from receiving fuel. This happened to flight BA38 in 2008 when ice in the fuel lines caused a dual engine flame out on final approach into London Heathrow. This was found to have been caused due to a an issue with the Boeing 777 fuel system. The quick actions of the Captain in making the decision to retract some of the flaps reduced the drag of aircraft which saved everyone on board.

Flame Out

This is where the ignition of the fuel stops. This could occur in extreme turbulence or very heavy rain / precipitation.

Volcanic Ash

This can damage the engines to the point that they flame out or stops the combustion process. In 1982, British Airways flight 9, a Boeing 747, lost all four of its engines due to ingesting volcanic ash. The aircraft glided outside of the ash cloud and managed to restart its engines before successfully landing in Jakarta.

Engine Separation

Believe it or not, there is a checklist on commercial aircraft for entire separation of the engine from the wing. The engine is held onto the wing by a ‘sheer pin’ to ensure the engine separates from the aircraft and protect the aircraft structure in the results of the engine suffering a significant impact.

How Much Fuel Are Aircraft Required To Carry?

How much fuel are aircraft required to carry?

How do you know you’ve got enough?

How much fuel are passenger jets required to carry?

The minimum amount of fuel which a passenger jet must carry is set out by regulators such as EASA and the FAA. Airlines are actually required to carry substantially more fuel for a flight than is required to get from A to B in case anything unexpected happens such as an airport closure or aircraft emergency. Commercial flights typically carry at least one hour’s worth of additional fuel on top of that required to get to their destination, but this is often increased by the pilots depending on the circumstances on the day.

Airlines must comply with the regulatory stipulations with regards to carrying fuel. Most authorities policies are broadly similar and are detailed in each Airlines operating manuals.

Under EASA regulations (although FAA and other authorities are very similar) the Captain must ensure he has the following minimum fuel before departure:

  • Trip Fuel
  • Diversion fuel or 15 mins holding fuel if flight is planned with no alternate
  • Reserve Fuel
  • Contingency Fuel
  • Taxi Fuel
  • Additional Fuel

Trip Fuel

Fuel required from the start of take-off, through climb, cruise, descent and approach to touchdown at destination, assuming departure on the SID from the assumed runway and arrival using the STAR for the assumed arrival runway and routing based on the forecast wind.

Diversion Fuel

Fuel required from go-around at destination, climb, cruise, descent, approach and landing at the selected alternate airport. This is normally calculated at the planned landing weight minus contingency fuel.

If no alternate is planned for the flight then the diversion fuel figure must be replaced by 15 mins holding fuel at 1500ft above destination airfield in standard conditions.

Reserve Fuel

Is the minimum fuel required to be present in tanks at at the alternate airfield (or destination if no planned alternate). The figure is calculated based on 30 mins of fuel holding at 1500ft in clean configuration at planned landing weight.

Contingency Fuel

This is carried to cover unforeseen variations from the planned operation. For example different winds / temps from forecast or ATC restrictions on levels and speed. It can be used anytime after dispatch (once aircraft moves under its own power). It cannot be planned to use before. More likely it is used for delays on departure or arrival.

Contingency Fuel should be the higher of (i) or (ii) below:

i. Either:

a. Not less than 5% of the TRIP FUEL required from departure to destination; or
b. If an En-route alternate is available and selected, not less than 3% of the TRIP FUEL required from departure to destination; or
c. An amount of fuel sufficient for 20 minutes flying time based upon the planned trip fuel consumption; or
d. Statistical Contingency Fuel (SCF).

ii. An amount to fly for 5 minutes at holding speed at 1500 ft clean at Planned Landing Weight.

The minimum contingency fuel to be carried must not be below 5 minutes at holding speed at 1500 ft clean at Planned Landing Weight, even for the purpose of an LMC fuel reduction

Taxi Fuel

This is fuel for APU burn on the ground, engine start and taxi out. Most airlines use statistical data to calculate this by using the taxi time in minutes.

Additional Fuel

Additional fuel is planned and loaded if the existing total fuel is not sufficient to cater for an engine failure (2 engines in 4 engine aircraft) or de-pressurisation at the most critical point along the route. Fuel planning must allow a descent and trip Fuel to alternate airfield, hold for 15 mins at 1500ft and make an approach and land.

Most airlines will work the total fuel required, which is presented to the pilots, through their flight planning system. The pilots will then make a decision as to whether they require any ‘extra’ fuel. There could be many reasons for requested additional fuel such as weather, ATC delays, an increase in passenger numbers or a technical defect.

Fuel Decision

The final decision as to how much fuel should be carried for a flight is always the responsibility of the Captain of the aircraft. The Captain will discuss the requirements to take any extra fuel with the First Officer prior to the flight commencing.

If you find this page of interest, check out are article about how much fuel a Jumbo Jet burns.

What Speed Does a 747 Take-off and Land?

What speed does a Boeing 747 Jumbo Jet take-off and land at?

A look at the speed the at which the Boeing 747 takes off and lands

What speed does a Boeing 747 take off and land?

Speeds vary according to performance, environmental conditions and weight but typically a fully loaded Boeing 747 on a normal long haul flight would take off from a typical length runway at around 160 knots which is 184 mph.

A typical fully loaded 747 would be landing at a weight of around 250,000kgs. The landing speed as this weight would be around 145kts-150kts (166mph-172mph) depending on the landing flap setting selected.

Engine Thrust

Most airlines and aircraft have a facility to de-rate thrust (or use assumed temperatures) for take-off. This occurs on runways where the aircraft has extra performance in hand e.g. the aircraft does not need the full length of the runway to take-off. Large commercial aircraft rarely use their full engine power for take-off as most runways at large airport long enough to support a reduction in thrust. Take-off thrust might be as little as 75% of the maximum thrust.

Taking off with reduced thrust reduces the temperature the various components in teh engine are exposed to. This in turn can significantly reduce engine wear and tear and thus maintenance costs, and ultimately extend the life of the engine.

Additional Speed for Landing

The greater the flap setting, the lower the take-off and landing speed. Jumbo Jets typically land at Flap 25 or 40. Pilots generally fly the approach speed faster than the actual touchdown speed to allow a speed ‘buffer’ in case of any airspeed fluctuations. This additional speed is ‘bled off’ during the flare or plain terms, the excess speed reduces as the nose is raised just before touchdown. In light wind conditions we would add 5 kts to the approach speed but in strong wind conditions up to 20kts can be added.

B747-400 Maximum Take-Off Weight

The xaximum take-off weight for the B747 is 396,000 KGS / 875,000 LBS

B747-400 Maximum Landing Weight

The Maximum landing weight for the B747 is 285,000 KGS / 630,000 LBS


Ever wondered how much fuel a Jumbo Jet burns? This page might be of interest.

How much fuel does a Jumbo Jet burn?

How much fuel does a Jumbo Jet (Boeing 747-400) burn?

What fuel does a jumbo jet use between London and New York?

How Much Fuel Does a Jumbo Jet Burn?

The four engines of the Boeing 747 Jumbo Jet burn approximately 10 to 11 tonnes of fuel an hour when in the cruise. This equates to roughly 1 gallon (approximately 4 litres) of fuel every second. It can carry a maximum of 238,604 liters of fuel and it has a range of about 7,790 nautical miles.

A Jumbo Jet (Boeing 747-400) flying from London to New York burns approximately 70,000 kilograms of fuel. Jet fuel has an approximate specific gravity of 0.85, which therefore equates to 82,353 litres.

Therefore, the cost of the fuel (based on 1 litre costing 31 pence) required to fly from London to New York is approximately £18,500 (€23,600). The cost of fuel for a a jumbo jet carrying 450 passengers, would work out as about £41 (€52) per person.

Dwindling Numbers

The worldwide Jumbo Jet fleets are getting smaller with none now in operational service with UK airlines. Both British Airways (BA) and Virgin Atlantic retired their B747 fleet earlier than planned due to the reduction in travel demand as a result of the COVID-19 pandemic in 2020. Some airlines continue to operate the B747-8, the latest passenger version of the Jumbo Jet, such as Lufthansa. Boeing plans on stopping production of the Jumbo in 2022.

Did you find this article interesting? You might be interested in: How much does jet fuel cost?

Why do Planes Fly so High?

Why do airliners fly so high in the sky?

Why do aircraft fly at high altitude? Is it to save fuel?

How High Do Passenger Jets Fly?

The average commercial passenger jet aircraft cruises at an altitude between 30,000 and 42,000 feet (ft) (9,000 – 13,000 meters). This means that aeroplanes usually fly between 5 to 7 miles up in the air. It typically takes around 15 to 30 minutes after take-off for the aeroplane to reach this altitude. The temperature of the air at this altitude is very cold, typically around -50 to -65C.

Why Do Commerical Aircraft Fly So High?

The reason aeroplanes fly so high is due to improved fuel efficiency. A jet engine operates more efficiently at higher altitude where the air is much thinner, allowing an aircraft to travel faster whilst at the same time, burning less fuel.

Flying above 30,000ft also has the benefit of allowing the aeroplane to fly above most weather systems making it more comfortable for the passengers.

Engine Efficiency, Airspeed & Density

Modern jet engines on commercial passenger aircraft (referred to as Turbo-Fans), are most efficient when they are operated at high altitude. This is because jet engines gain an efficiency benefit when they are run at close to their maximum RPM limit or maximum (exhaust) temperature limitations. At lower altitudes, the engines can only be run at maximum thrust during take-off or perhaps the climb or else the aircraft would quickly exceed its maximum speed limitation. If you tried to fly straight and level at 10,000ft with more than 70% thrust set, you would quickly overspeed most commercial jet aircraft. At 70% thrust, the engine isn’t running very efficiently.

As the aircraft climbs in altitude, the jet engines produces less thrust (as the air is thinner), but it maintains a high compression ratio and thermal efficiency. As the air is thinner, the plane is able to achieve a much higher True Air Speed (TAS) than lower down, meaning the aircraft travels much faster whilst the engines burn less fuel.

The higher the altitude the less dense the air, or put in a different way, the thinner the air is. Therefore there is less resistance (or friction) to stop the aircraft moving through the air. We call this resistance “drag”.

High Altitude

Here’s an example to demonstrate how the air thins out as you get higher; imagine moving your hand through water and golden syrup. If you want to move your hand through both of these liquids at the same speed, you need much more effort to move your hand through the golden syrup than the water. This is the same principle with an aircraft flying at a higher altitude when compared to a lower altitude.


If you found this article of interest, check out our page on How fast do planes fly?

Can a plane fly if all its engines have failed?

What happens if all the plane’s engines fail in the air?

If all the aircraft’s engines fail, will the plane still fly or will it fall out of the sky?

Can a plane fly if all its engines have failed?

An aircraft will glide perfectly well even if all its engines fail. In fact, the chances are that if you’ve flown in a plane, you’ve seen it effectively glide at some point during the descent to land. Aircraft are able to fly through the movement of air passing over the wings and as long as this process continues the aircraft will continue to fly. If both engines fail, the aeroplane is no longer being pushed forwards through thrust, therefore in order to keep the air flowing over the wings, the aircraft must exchange energy through losing altitude in order to maintain forward airspeed. The aircraft doesn’t have to lose altitude particularly rapidly to keep flying and therefore it both engines were to fail a high altitude, the aircraft may have as much as 20 – 30 minutes of airbourne time to find somewhere to land.

How Far Can a Jet Travel with no Engines?

Here’s an example. A typical commercial aircraft has a lift to drag ratio of around 10:1. This means that for every 10 miles it travels forward it loses 1 mile in altitude. If an aircraft is at a typical cruise altitude of 36,000 (which is 6 miles up) and loses both engines, it can travel a forward distance of 60 miles before reaching the ground.

US Airways Flight 1459

Rest assured, dual engine failure is almost unheard of. We all know about the story of US Airways flight 1459 landing in the Hudson River in New York after both its engines were destroyed by birds, but that really was exceptional – and everyone survived thanks to the quick actions of the actions of the pilots Captain Chesley Sullenberger (‘Sully’) and First Officer Jeffrey Skiles.

Air Transat Flight 236

One other exception was Air Transat Flight 236. The plane had a fuel leak causing both engines to fail at approximately 65 nautical miles from Lajes Air Base in the Azores. With an average descent rate of 2,000 fpm, the aircraft glided without power to the airbase where the crew carried out a successful landing about 17 minutes after the last engine failed.

Gliding Every Flight

The lower the engine power, the less fuel the engines burn. On most flights pilots try and burn as little fuel as possible and part of this process involves descending the aircraft towards the destination airport at idle (minimum) thrust. When the thrust is at it’s minimum setting, it isn’t really producing any meaningful thrust at all so the aircraft is effectively gliding. Therefore you will have experience the aircraft gliding on almost every flight you have been on!

If you found this article of interest, you may find our article about how both engines on a passenger jet can fail to be worth a read.

Can A Plane Fly With Only One Engine?

Can a passenger jet fly with only one engine?

What happens if an engine fails in flight?

Can a passenger jet fly with only one engine?

Yes it can. A twin-engine aircraft can fly perfectly well on only one engine. In fact, it can even continue the take-off and then safely land with just one engine. Losing an engine in flight is not usually a particularly serious problem and the pilots are given extensive training to deal with such a situation.

What do the pilots do if an engine fails?

All pilots are taught to abide by a basic aviation rule regardless of the severity of any airborne event. This is summarised by the acronym; Aviate, Navigate, Communicate. The crux of this is to ensure the flight crew prioritise flying the aircraft first, ensuring that it is fully under control before verifying or correcting its navigational path and making sure it is flying where the pilots want it to fly, i.e. not heading towards a high mountain. This is followed by communicating the relevant information to all the appropriate parties, starting with Air Traffic Control.

There are several different severities of engine problems that might require slightly different responses from the flight crew, defined by the level of urgency. For example, if an engine fire is indicated, this requires an immediate response after ensuring the aircraft is under control (‘Aviating’!). If for example, there was an engine fire indication, there are several ‘Memory Actions’ for the flight crew to complete. This will involve completing the engine shutting down, and subsequently deploying the fire extinguishers from memory, without the aid of a checklist. Once the engine is safely shutdown and the fire extinguished, the crew would reference that the ‘Engine Fire Memory Actions’ had been completed correctly by referencing the appropriate checklist. The checklist will then detail further tasks for the crew to complete that were not included in the ‘Memory Actions’.

On the other hand, if it was a straight forward engine failure with no damage indicated, there would be no ‘Memory Actions’ and the pilots would follow a checklist to diagnose and potentially restart the engine from a checklist rather than from memory.

Any engine failure on a twin-engine aircraft will require the pilots to land the aircraft at the nearest suitable airport. Statistically this is unlikely to be your destination unfortunately!

‘Memory Actions’ for an Engine Fire or Severe Damage

Different types of aircraft may have different names for the various switches, handles and procedures, but the basic principle remains the same; to safely shut down and secure the engine in a timely manner. These steps are typically as follows:

  • Disengage the Autothrottle – this stops automatic thrust control.
  • Reduce the thrust on the damaged engine to idle – this involves moving the respective thrust lever all the way back to its idle position.
  • Fuel control switch to off – this closes the fuel valve, stopping fuel flow to the engine.
  • Pull the fire handle switch – this typically disengages the electrical, hydraulic, pneumatic and fuel systems from the respective engine.
  • If a fire is still indicated in the engine, turn the engine fire handle to discharge the first fire bottle. After waiting around thirty seconds, if fire indications are still present turn the fire handle the other way to discharge the second fire bottle.

Crew Co-ordination

Each of these actions MUST be verified by both crew members. For example, the pilot completing the checklist will touch the respective control switch, such as the Fuel Control Switch, and the other pilot will confirm they are about to action the correct switch prior to moving it. It is required to be completed at a reasonable pace (not rushing through) to ensure the wrong engine is not shutdown.

The engines are designed to contain any fire within it’s housing to stop it spreading to any other part of the aircraft. However, if an engine fire continues after this procedure has been followed, the flight crew may need to consider an immediate landing and in very severe cases, this may mean a forced landing away from any airport. However, rest assured, the potential of such an occurrence is unbelievably remote.

Reasons why an engine might fail or be shut down by the pilots:

  • Fire
  • Severe Damage (for example a turbine/fan blade separation or bird strike)
  • Separation from the aircraft
  • Surge
  • Stall (an engine stall is different to the aircraft wing stalling)
  • Fuel Starvation or Contamination
  • Flame Out
  • High vibration
  • Limitations exceeded (too hot for example)

What are the implications of an engine failure?

Asymmetric Thrust / Controllability. The first implication is the asymmetric thrust that will be produced. If an engine fails and is shutdown, the other engine’s thrust is increased to stop a decay in airspeed. This results in the aircraft wanting to turn away from the working engine and entering a turn. If left unchecked, this will result in loss of control of the aircraft. This usually has to be corrected manually by the pilots through the rudder pedals. Any time there is an adjustment in speed, thrust or altitude, the pilots will need to ensure the aircraft remains balanced and in control.

Altitude. With 50% of the aircraft’s power no longer available it will not be able to maintain its cruise altitude. If the aircraft is in the cruise at the time of the failure (which is statistically most likely), a descent will need to be quickly initiated to an intermediate altitude which can be maintained by the remaining engine (typically between 15,000ft – 25,000ft for most aircraft, depending on weight).

System Redundancy. Many of the aircraft’s systems are powered by its engines. These usually include the Hydraulics, Pneumatics (which provide cabin air) and Electrics. Whilst these systems have a level of redundancy (in part through the other engine), some parts of the system may no longer be available which could affect aircraft handling and performance.

Landing Performance. Losing an engine often requires a different flap configuration for landing, in part due to the performance that must be achieved were the aircraft to abort the approach/landing and conduct a ‘go-around’. Landing with a lower flap configuration increases the landing distance required and therefore the pilots must carefully consider which airport they elect to land at. Airport weather, runway length and aircraft weight all play a part in these considerations.

What is the most dangerous phase of flight to have an engine failure?

For a pilot, the most testing place to have an engine failure is during the take-off phase, i.e. the start of the ground roll until the aircraft passes around 1,500ft. However extensive training is provided for this scenario and the pilots are tested on their reactions to such an event every six-months in the simulator. They must safely deal with such a scenario to a high standard or they will not be allowed to continue to fly until adequate performance is demonstrated.

During the take-off, the pilots use a carefully pre-calculated speed called V1 (pronounced “Vee One”) to determine their actions were an engine to fail. During the take-off roll, if an engine failure occurs before the V1 speed, the pilots must abort the take-off, which is known in the industry as a ‘Rejected Take-Off’ or RTO for short. If they elected to continue, the aircraft would not gain enough speed to take-off with the remaining engine power available on the runway length remaining.

If a failure occurs after V1, the pilots must continue the take-off and get airborne. If the pilots tried to abort the take-off at this speed, there would not be enough runway left to safely bring the aircraft to a stop.

Once the aircraft is in the air, the pilots will just concentrate on flying and controlling the aircraft until approximately 400ft. At this altitude, they will review what has occurred and carry out any ‘Memory Actions’ if required.

What happens if you lose an engine on an aircraft with more than two engines?

A four-engine aircraft losing a single engine is even less of an issue. A few years ago, a four-engine Virgin Atlantic Boeing 747-400 (a jumbo jet) had an engine failure over the United States en-route to the UK. The aircraft continued all the way over the Atlantic Ocean back to the UK without any further problems.

If a four-engine aircraft lost more than one engine, it can still potentially fly at a lower altitude and will perform better at lower weights.

What are the chances of an engine failure?

With the significant technological improvements that have occurred over the last few decades, engines are built to an incredibly high standard and are very robust as a result. Over the last few decades, engines failures have become increasing rare to the point that the majority of pilots will now only see an engine failure in the simulator over the course of their career.

Safety statistics suggest that less than one in every one million flights will have an engine failure or forced engine shutdown in the air or on the ground. This works out at approximately 25 such failures a year across commercial aviation.

If a failure does occur, the engine is designed to contain any problems and stop it spreading to the rest of the aircraft. For example, if one of the fan blades at the front of the aircraft detaches, the engine casing should stop it leaving the engine.