Take-off- Loss of Control
Loss of control on the ground (LOC-G) is most common during the take-off phase of flight and is often the result of the following factors:
· Insufficient control of the aircraft while still on the ground
· Incorrect rotation airspeed
· Wrong aerodynamic configuration
· Crosswind exceeding pilot/aircraft capability
· Selecting the incorrect aircraft attitude at rotation during the initial climb
Take-off is commonly considered to be one of the riskiest phases of flight, the other being LOC-I (Loss of Control in-flight) on landing. Data on LOC-G and LOC-I accidents, both fatal and non-fatal, indicate that this is the risk group which contains the highest number of accidents and incidents within the UK.
What can go wrong in this phase of flight?
Of course, the aim of the take-off is to leave the ground, hence why, if things go wrong, many pilots end up trying to press on, which can lead to carrying out incorrect actions and making the situation worse.
This can be exacerbated by the fact that take-off is a very busy phase of flight, with a lot going on all at once. For example, in the case of stalling due to rotating at the incorrect airspeed, pilots should try to resist the urge to keep pulling back on the stick/yoke (with the intention of continuing the take-off), as this will increase the angle of attack and worsen the situation.
Instead, the attitude should be reduced to either, build airspeed, or, if there is enough runway left, being prepared to land and abort the takeoff. This of course, is all well and good in the cold light of day sat in your armchair whilst flicking through the latest safety sense leaflets, but seeing this through in a real-life scenario involves knowing several things:
1. Thinking about situation beforehand and knowing what you will do as and when it arises (preparation and planning)
2. Recognising and quickly diagnosing correctly what is going wrong
3. Carrying out the correct actions to rectify the situation (performance)
Preparation
The key of a successful take-off is preparation! Carefully consider your aircraft configuration, its performance, weight and balance (when was the last time you looked through the performance section of the Aircraft Flight Manual?), the length of the runway, as well as the outside temperature and wind strength and direction.
Always check the weather: Do not bet your life on the weather staying the same after opening the curtains first thing in the morning. Make sure that the weather is good enough for you to undertake your flight whilst taking into account your personal experience and qualifications. If in doubt, postpone.
Some other preparation factors to consider are:
Runway: Are you operating on a grass runway? Is it wet? Is there any specific standard take-off procedure? Remember a grass and/or wet runway will increase friction and thus increase your take-off distance. Moreover, a wet runway will increase your braking distance in the event of an emergency, and you may face aquaplaning followed by a potential loss of control on ground.
Temperature: The effect of temperature on take-off performance, especially in summer, can be dramatic. Have you heard about density-altitude? Do you know how to calculate it and take its effect into account?
Take-off distance: Be sure that the runway length (TORA, Take-Off Run Available) exceeds the take-off distance required for your aircraft.
Wind conditions: Check the wind direction so as to take-off with a headwind (unless special procedures or circumstances prevent to do so). If you are forced to take-off with a tailwind, have you checked the TORA is still suitable for your aircraft configuration? Depending on the weather, be prepared to encounter a crosswind or gusts.
Departure: Are there any obstacles on the initial climb path? Are you departing from a high altitude aerodrome? Does the departure require a low altitude turn that may cause problems given today’s weather? Are there any NOTAMS that require a amendment to your departure today?
Aircraft weight & balance: Check you are operating within the manufacturers approved limits. Check seat attachment points and secure all objects to avoid unwanted movements during the acceleration phase, at rotation or during climb.
Take-off parameters: Review power settings, slats and flaps configuration (if any) and fuel-air mixture control (when applicable), etc. always refer to the documentation provided by the aircraft manufacturer. If in doubt, do ask an instructor or a trusted, experienced peer.
Pre-flight inspection
Inspect the aircraft to ensure it’s serviceable. The walkround is a good time to identify any issues that could cause problems during takeoff (and indeed the whole flight). Make sure to check that the stall warner is working, remove covers from pitot tube(s) and static port(s) and double check that all the surfaces are clean and debris free.
Pre take-off checks
Start your engine(s) and complete checks following a checklist. This will help to detect possible malfunctions that could lead to a loss of power at take-off.
Check that all controls offer free and correct movements and adjust trim to take-off position.
Check the brakes. Correct braking performance is necessary to safely stop the aircraft in case of a rejected take-off. And remember, use a pre take-off checklist before taking off so you don’t miss anything.
Pre-take-off briefing
Near the holding point, verbalise your pre-take-off briefing aloud, even if you’re on your own. This will increase your preparedness and your ability to manage unexpected situations. Include elements in your brief such as the rotate speed, flaps/slats setting, power settings, target climb speed and any specificities of the airfield e.g. obstacles in the take-off path or urbanisation around the airfield that might require special attention.
Voice what your flight plan contains after take-off, together with any actions you will carry out in the event of an emergency prior to rotate and minor or major failure following take-off. Also, state at which height you will change the slats/flaps configuration and the associated target climb airspeed. Finally before lining up on the runway, double check that the approach and runway are free of incoming or outgoing traffic (even if ATC have cleared you to line up).
Take-off
Align on the runway centreline to initiate the take-off. There is no point hugging one side of the runway as this gives you less time to react if an issue occurs as you may find yourself having departed off the side of the runway before you know it! Accelerate while keeping the aircraft on the centreline. Check that the airspeed indicator is working and that take-off power is available (as per the indication of the rev counter – RPM, torque, etc.) and check for any warnings at periodic times during the take-off roll, for example:
“speed reads, good acceleration, no warnings”,
“55kts, rotate, no warnings”
“70kts, positive rate of climb, no warnings”
Pay attention to the airspeed and aircraft attitude. When reaching the rotate speed, smoothly pull back on the stick/yoke to set the take-off attitude at which point the aircraft should take-off. Excessive pitching can lead to exceeding the critical angle of attack (AoA), leading to a stall.
Initial climb
Once the airspeed reaches the target initial climb speed, wait to reach the minimum safe height to change slats/flaps configuration and target the climb airspeed.
If you plan to turn during the climbout, don’t overbank too much otherwise you may find that the climb rate reduces too much. Instead, keep the bank angle below the reference value suitable for your aircraft type (such as 20°) so that you keep climbing. Take-off is by no means a difficult manoeuvre but it, due to the many factors at play (weather, runway condition, aircraft state etc.) it does require preparation, to ensure a solid performance every time.
Further reading
· Weather Wise: Beyond Go/No-Go
· Proficiency: Behind the power curve, Where it takes more power to fly slower
· Take-off and Landings: Normal Take-offs
· Take-Offs and Landings: Determining an Abort Point
· SIB 2009-10R1 : Monitoring of Take-off Slats/Flaps Settings during Departure
· Loss of Control During Take-off and Landing