Happens if an Airplane's Engines Fail?
A vertical crash dive
down and into the ground is unlikely to
happen - your plane can safely glide down to land if it
Your problem is not the
descent, but may be the actual landing itself.
NOTE : This article reflects a
mixture of my own opinion (most of my own flying has been in
gliders) and that of senior airline pilots. The complex
issues have been simplified and due to the happily
infrequent nature of such events, our guesses may or may not
accurately describe any potential future scenario.
The good news - it is
exceedingly rare for a plane to lose power in all engines, which
(along with the better economy enjoyed by two engined planes
compared to four engined planes) is offered up as a reason for
reducing the number of engines on planes, and allowing them to
fly further away from airports on over the water routes.
even better news - if a plane does lose engine power, while
cruising at normal speed and altitude, you're probably going to
land safely - assuming there's somewhere moderately level and
unobstructed for the plane to land.
What Might Cause Jet Engines to
Modern jet engines are
incredibly reliable. Add to their designed reliability the high
quality of regularly scheduled maintenance, and there are very
few times when an in-flight problem occurs. In addition, modern
engines automatically monitor themselves, conducting
computerized self-diagnostics and analyzing their actual
performance while in flight, and automatically radioing ahead to
an engineering base if it thinks something is not fully perfect.
Occasionally a plane will land and be greeted by maintenance
engineers - the pilot will ask 'Why are you here' and will be
told 'Your number three engine's computer advised us that we
need to check its second stage bearings' - something the
two pilots didn't even realize was an issue!
However, nothing is
infallible. Occasionally the turbine blades might break. Another
source of turbine fan damage comes from ingesting foreign
materials - either something loose on the ground or (quite
common) a bird.
Then there may be some type
of external problem that affects the engine - something might go
wrong with the electrics or the fuel or lubrication or even air
supply. The fuel might contain impurities that damage the
engine, or the plane might simply run out of fuel. And, in one
famous situation, a plane flying through the plume from an
erupting volcano lost power in all its engines due to the
impurities in the air.
Most problems that can occur
typically affect only one engine. And any modern two or three
engined passenger plane can operate more or less normally on
only one engine for an extended period of time (ie for some
hours). A four engined plane will work happily on two engines,
but with only one engine it becomes a sort of 'super long range
How Common is it for a Plane to
Lose Power in All Engines
Very uncommon. This might
happen, somewhere in the world, no more often than once every 5
- 10 years.
Losing Power in Some but not
This sometimes happens, and
the chances are that you'll probably never even know that it has
occurred (on a four engined plane).
Of course, while you might
not know anything about the loss of power in an engine, for sure
the pilots on the flight deck are very aware of such a
situation. If they can't restart the engine and assure
themselves that the problem is resolved, they may
divert the plane and land it at a nearby airport. They'll
probably not urgently land the plane at the first airstrip they
find, but instead will selectively choose an airport with a
suitable runway, and hopefully with both engineering and
emergency services available.
In such a case, the airport
fire department will probably deploy just in case something else
goes badly wrong at the last minute, but that is nothing to
worry about. The typical airport fireman must lead an incredibly
boring life - most of them will serve their entire lives without
a single real full scale emergency!
Note the the use of the
phrase 'they may divert the plane'. There was a case a
couple of years ago where a BA 747 lost power in an engine
shortly after taking off from Los Angeles. Rather than
return the plane back to LAX, the pilots - with BA's approval -
chose to fly the plane all the way to London, including going
over the polar route where at times the nearest normal airport
was somewhat distant.
Many commentators felt this
to be inappropriate, but the plane had no further problems -
apart from running out of fuel and having to land short of
London, in Manchester. Strangely, a plane burns more fuel
flying on three engines than four in a case like this - it has
to fly at a lower altitude and the greater air friction
increases the fuel burn rate.
Losing Power in All Engines
The pilots don't have much
choice if they lose power in all engines. They're for sure
going to have to land the plane. But don't panic (and your
pilots won't be panicking either). Statistically
you have a very good chance of surviving such a situation.
If a plane loses all power,
it does not then fall out of the sky. Instead it becomes a very
big and rather clumsy glider, but it has the same
controllability as with engines, although perhaps not quite as
readily as before. It can still maneuver left and right, and can
also vary its rate of descent, but it no longer can go up or
stay flying level.
A plane can land without
needing to use its engines. Gliders (sailplanes) do it all the
time, and there is no reason why a passenger jet can not land
without engine power as well.
Modern jets don't have
sufficient batteries to supply power to the plane's hydraulics
and control systems in the event of engine failure. However, an
air driven generator will deploy into the airstream, and the air
passing through its blades will spin this generator, enabling it
to create some limited emergency power.
It is likely that the
plane's cabin pressurization will also fail. This would be a
gradual failure, and then you'd get to see the oxygen masks
dropping down in front of you. There is ten to fifteen minutes
of oxygen supply through this system, and by the time it was
used up, the pilot will have smoothly glided the plane down to
below 15,000 ft, at which point you'll no longer need the
Power loss while taking off
This is the worst case
scenario. All modern planes can continue their take-off
procedure with the loss of one engine (even if they only had two
engines to start with) but if they lose all power in all
engines, then the pilot has very little time or opportunity to
urgently turn the plane around and to return back to the
airport. Worse still, in many cases there is nowhere immediately
ahead of the plane to safely land - just city.
For smaller (more
maneuverable) twin-jets (eg 737s and A319s), after probably five
minutes of flying, there is a good chance that the pilot can
turn the plane around and land it back on the runway he took off
from. However, even this is not always as simple as it sounds -
in conditions of poor visibility, for example, it may not be
easy to urgently get a visual fix on where the runway is!
For a large less
maneuverable and fully loaded 747, keep your fingers crossed for
perhaps ten minutes.
Power loss while landing
This can also present as a
problem, due to the way that planes land at most airports. The
plane doesn't have (and doesn't want!) any 'spare' energy (in
the form of either excess height or speed) during the final five
minutes or so of its landing, and a sudden loss of power two or
three minutes out from touchdown will probably require the pilot
to attempt to land somewhere short of the runway.
Power loss while cruising
If the plane loses all power
while at cruise altitude, the first thing the pilot needs to do
is to realize that he has irrevocably lost power and to switch
his focus from trying to recover power to planning how and where
to land. It can take a minute or two for this realization to
dawn, but pilots are required, as policy, to immediately assume
the worst - while still, of course, doing all they can to bring
about the best possible outcome.
He should then climb steeply
so as to convert the extra forward speed into extra height. The
higher the plane gets, the less air resistance, the slower it
will be flying, and the more range it will have. The pilot will
probably get another thousand or two feet of altitude before the
plane slows down to its most efficient glide speed, which is
somewhere between 200-225 mph.
So, there you are, in a
plane at, say, 35,000 ft, with no power. Your plane can probably
travel ten to twelve times as far in a forward direction as it
has height to lose - so at 35,000 ft, the plane can go about 85
miles, maybe more.
The plane will also have
about 20 minutes of flying time before the altimeter reaches
Which then leads to a very
big question - is there a place to land within 85 miles of where
the power loss occurred? When you keep in mind that this gives
the pilot not just 85 miles of straight ahead, but also nearly
as much travel to each side, and perhaps 70 miles back the way
he came, that gives him almost 20,000 square miles of territory
in which to hope to find an airport.
In most of the US, there's a
good chance that there will be an airport within that area.
A 757 that landed in Costa Brava, Spain, during a storm
in 1999. All 233 people on board survived.
A modern jet plane needs a
mile or even two of runway to land on. They typically land at
about 130-160 mph, and need this distance first of all so that
they can land within a broad zone of the ideal spot to touch
down, and then secondly, they need the distance to brake and
Although modern jets have
'reversers' on their engines that most pilots like to use to
help slowing down, they aren't very effective, and are not
essential. The main way that the pilot slows the plane down is
very simple - he steps on the brake pedal (or, to be more
precise, he sets a little lever to low, medium, full or auto
braking, then watches the plane's autopilot do the braking for
An airport runway has three
essential characteristics (plus other not quite so important
features). The three essential characteristics of a suitable
runway are :
It is straight and flat
It is long (ideally a mile or
more in length)
It is strong, able to support
the massive weight of a passenger plane supported on only
three sets of wheels
It is well lit to help the
pilot's visual approach (and probably has electronic landing
aids as well)
If a pilot can't find an
airport runway with these characteristics, he then starts
looking for the next best thing. This is almost certainly not a
length of freeway, unless he is able to coordinate with the
highway patrol to clear a couple of miles of freeway for him to
land on (almost certainly impossible with the limited time
There are two types of
non-airport landings. In both cases, the pilot will try to land
as absolutely slowly as possible - instead of a normal landing
speed of 130-160 mph, if he can lower the flaps, he'll probably
be able to bring the speed down to as little as 115 mph (even
the small seeming reduction in speed from 160 mph to 115 mph
will halve the plane's kinetic energy and ability to do damage
to itself and its passengers).
He'll also be dumping fuel
(if this is possible with the reduced power the plane now has),
not only to reduce the danger of fire upon landing but also to
reduce the weight of the plane. Less weight makes it easier to
land on a less strong surface, allows it to land at a slower
speed, and gives the plane less momentum (at any speed), making
it easier to stop.
Not an airport, not a runway,
but still on land
This is difficult, but not
as difficult as it might first seem.
Logically, the plane is
either over a developed urban area, which reasonably implies the
presence of an airport nearby, or alternatively, it is over
undeveloped area, which hopefully means open fields (but not
mountains!). Even if the plane is flying over a mountain range,
the chances are that within its 85 mile radius of remaining
flight (assuming it was at reasonable altitude to start with), it will be able to find an area of flat ground.
The landing will be rough,
for sure. The pilot will probably try and keep the nose up in
the air as long as possible, but then it is going to come down
with a sudden thud. The undercarriage will almost certainly
break off , and then the engines will be ripped off the wings,
leaving the remains of the plane fuselage and wings to slide
over the ground and perhaps spin around before coming to a stop.
You'll be shaken violently every which way, but if nothing bad
happens, the plane will gradually come to a stop, and hopefully
with no fires breaking out. If you survive the first 30 seconds
of the landing, you're probably going to be okay.
An A320 shortly after it landed in the Hudson River, New
York, on 15 January in the mid afternoon. All 155
people on board survived, and some didn't even get wet.
Who hasn't looked at the
life jacket or 'flotation device' part of the flight attendants'
safety demonstration and laughed cynically about surviving long
enough to need such things 'in the event of a water landing'?
Well, the news is basically
good. There have been a number of cases where passenger jets
landed in the sea, and even in the case of a 'bad' water landing
(the pilot dropped a wing into the water too soon, causing the
plane to cartwheel and break up) there was still an almost 30%
If you remember back to the
four characteristics of an ideal runway, water actually
possesses hopefully two of them. It is straight and flat
(assuming that it is calm - waves will complicate things) and
As everyone knows who has
hit water at speed, it is surprisingly unyielding at speed, but
this doesn't equate to the 'strong' characteristic - it won't
support the weight of the plane on its undercarriage, indeed,
the pilot will probably choose to land the plane with the
When the plane first hits
the water it might skip, like a stone bouncing along a pond. Or,
it might nose down and tunnel into the water. If it does this,
don't worry. It will quickly lose speed and then rapidly rise
back to the surface before too much water enters the plane.
Assuming the main fuselage
is reasonably intact, the plane would probably float on the
water for long enough for the passengers to get out the
emergency exits and into the life-rafts. The plane can be
completely evacuated in 3 - 5 minutes.
The US Airways A320 landing in
the Hudson River, 15 January 2009
This is a very relevant and
recent example of a modern jet making a water landing. The
flight had just taken off from La Guardia when it hit a flock of
birds (believed to be geese) and apparently lost power in both
The pilot wasn't in a
position to allow him to turn and return to La Guardia, or to
fly to any other airport, so he chose to land on the Hudson
River near mid-town Manhattan, less than five minutes after
The landing was reasonably
smooth, and the plane didn't break up. The plane was
completely full with 150 passengers, three flight attendants and
two pilots, and everyone was able to safely make their way to
the over-wing and front exits and get off the plane. The
plane slowly settled, tail first (this is typically what you'd
expect in a water landing); many of the passengers waited on the
wing for the rescue boats, which were on the scene extremely
quickly, to take them off; others boarded liferafts.
Summary and Reference
The chances of a plane losing
power in all engines is very close to zero.
If a plane does lose power in
all engines, it can probably glide to a regular airport and
land safely there.
If there isn't a suitable
airport close enough, then your chances of surviving a
landing either at sea or in the best approximation to a
runway that the pilot can find are better than 50:50 in your
Daytime landings, at places
other than airports, are easier than nighttime landings.
This site has interesting information on past water landings
and what happened in each case.
This site gives details of a 767 that ran out of fuel in Canada
in 1983 (colloquially known as 'the Gimli Glider'). And these two sites (here
here) give details of an Airbus A330 that glided to a
landing in the Azores.
Lastly, a Joke
Paddy and Seamus were flying
from Boston to Dublin on a 747. Half way across the Atlantic,
there was a loud noise outside the plane - one of the engines
fell off the wing.
A short while later the
captain announced 'Ladies and gentlemen, we're very sorry to
advise that we have lost one of our engines. However, there is
no need to worry - the plane can fly perfectly safely on three
engines. However, because we now have one less engine, we're
unable to fly quite so fast, and we estimate that we'll now be
approximately 45 minutes late arriving into Dublin.'
Seamus nodded to Paddy, and
they each calmly ordered another Bushmills.
The flight continued, then
all of a sudden, the plane lurched sharply to the left, then
straightened up again. Paddy looked out the window, and saw
flames streaming out of one of the two engines on that wing.
After a minute or two, the flames died out.
The captain made another
announcement. 'Ah, sorry about that, but we've just had a fire
break out in one of our three remaining engines. Fortunately,
the fire extinguishing system worked perfectly, but of course
we've had to shut that engine down. Don't worry - we still have
two perfectly good engines, and the plane is continuing safely.
So as not to overstress the two remaining engines, we're cutting
back our cruise speed, and estimate that we'll now be about two
hours late arriving into Dublin'.
Seamus and Paddy looked
anxiously at their watches, then relaxed and ordered another
Well, bad things happen in
threes. Half an hour later, Paddy said to Seamus 'Did you hear
that - the engines sound different?'. They discussed what that
might mean for several minutes, and then the Captain's voice
came over the announcement system again.
'Ah, ladies and gentleman, I
don't quite know how to tell you this, but we've had a problem
with another engine. We've had to shut it down, but, if my math
is correct, that still leaves us with one perfectly good engine,
and I promise you we're going to look after that one very
carefully, all the rest of the way to Dublin. We'll probably now
be about three or four hours late.'
Seamus looked at his watch,
calculated when they would now be arriving into Dublin, and said
to Paddy 'We're running very late already. I sure hope we don't
lose the last engine or else we'll be up here all day'.
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14 Mar 2003, last update
25 Aug 2018
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