Ever since aviation began, as far back as the early 1900s,
there have been accidents and incidents of some description. Lessons have
and will be learnt because these kind of events will never be eliminated
completely, only possibly reduced. Day by day, air travel is getting safer,
but when things go wrong it is at a high cost. We take for granted the safety
of the airliners we fly on, forgetting the possible problems that may occur
before or after the aircraft leaves the ground. This section explains what
problems the flight crew or the aircraft can encounter on any such flight.
Here, a Training Captain on widebody twin-jets for a major British airline
talks us through the hazards faced during an airliner take-off.
Thirteen Hazards on Take-Off
1:VEHICLES
Airport
Vehicles require clearance from the tower before approaching or crossing
the runway, but at some airfields overseas this rule is not often adhered
to.
2:LANDING
AIRCRAFT
At any airfield
there is a slight danger that aircraft can land over the top of you as you
line up ready for take-off. Air traffic control and the landing pilot should
always have the situation under control, but a look along the final approach
course before turning onto runway will reassure you there is no
danger.
3:SLUSH/WATER
ON RUNWAY
Most modern
runways are well drained, but some large puddles can develop. These puddles
and slush conditions inhibit the wheels as they roll down the runway, causing
a loss of performance.
4:BAD
VISIBILITY
With modern
aircraft this is less of a problem, but in poor visiblility obstructions
on the runway may not be seen until it is too late.
5:CROSSWIND
With a large
aircraft, crosswinds present little problems in terms of keeping direction,
but at the point of rotation it is easy to drop a wing slightly as the cross
gust catches it.
6:TIREBURST
A tireburst
can cause a considerable tendancy to pull to one side and in the early stages
of the take off run it is advisable to abandon. At higher speeds the abandonment
becomes more dangerous than the tire problem, so its better to continue the
run.
7:BIRDSTRIKE
Single
birdstrikes may render systems such as pitot tubes useless, or may obscure
vision for one of the pilots, but for larger aircraft its more of a nuisance
than a danger.
8:HIGH
CLIMB ANGLE
Rotating
to the right climb angle is important straight after take-off. If the angle
is too high the aircraft may not be able to cope adequately with the loss
of lift from ground effect, flap retraction or more importantly the loss
of an engine.
9:LOW
CLIMB ANGLE
Climbing
out at too low an angle after rotation can also prove dangerous. Flap retraction
limiting speed may be exceeded quickly, but more of a danger is that the
low climb out may put you on collision course with
obsructions.
10:MID-AIR
COLLISION
This is
a danger throughout the whole flight profile, but at low altitude and in
the proximity of airports the danger is increased.
11:ENGINE
FAILURE
Engine failure
is the biggest worry on take-off; it can occur at any time. Slower than V1
you abandon the take-off, remembering you have reduced reverse thrust available
to aid braking.
12:BAD
WEATHER
Thunderstorms
are a real danger, and you would never fly straight into them. Windshear
is another problem, when your headwind may suddenly drop and become a tailwind.
An extreme case is the "microburst," where you encounter a mass of downward
rushing air which forces your aircraft back into the
ground.
13:SYSTEM
FAILURE
There are
many systems which can go wrong on take-off, and when you are notified of
these by observation or warning lights you have to decide whether to proceed
or abandon. Above 100 knots it is usual to continue take-off if the system
failure is not major.
Below are a few examples of major accidents that have happened after
one of these unfortunate events have occured.

Engine Fire
Occasionally the hazards of take-off become tragically real. This British
Airtours Boeing 737 suffered a port engine fire during the early part of
its take-off run from Manchester, UK in 1985. 54 people died in the resulting
cabin fire. |
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System Failure
The loss of the port engine on this American Airlines
DC-10-10, on the 25/5/1979, caused the aircraft to crash into the ground
after take-off due to the fact that vital indicators were disabled on the
flight deck panel after electrical systems were ripped out after the impending
engine loss, catching the crew unaware, by which time it was too late to
save the aircraft . |

Bad Weather
This Pan Am Boeing 727 crashed on takeoff from
New Orleans after encountering microburst induced windshear |

Birdstrike
A black headed gull weighing just 10 ounces caused the catastrophic damage
to this Boeing 737 engine. Secondary damage caused by shedding turbine blades
can involve the severing of vital hydraulic lines, puncturing and ignition
of fuel supplies and the depressurisation of the aircraft. |
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