Basics, Application of Standard Procedures
Chapter 12.1
Application of Standard Procedures
Take-off and initial climb are combined standard procedures, in which the knowledge and techniques learned separately in the four basic chapters must be applied in a coordinated manner.
Mass and Balance
Before each take-off, a mass and balance (center of gravity) shall be calculated using actual flight data.
Performance
The PERFORMANCE concept summarizes the aircraft performance calculations for the current conditions and the corresponding phases of flight.
The AFM contains data on the required runway length for the take-off run and overflight at the end of the runway. For the preparation of a take-off, a comparison between the required runway length and the available runway length should be made, and this is done using the corresponding performance tables in the AFM.
Performance
To calculate the take-off distance, the current air density is required. The air density of the departure aerodrome is calculated from the aerodrome altitude, atmospheric pressure (QNH) and temperature.
Performance
Airport Elevation
Altitude of the airport above sea level
Example: 1500 ft / AMSL (above mean sea level)
Performance Charts
Other Influences on Take-off Distance
SURFACE CHARACTERISTICS
SURFACE CHARACTERISTICS data describes the nature of the runway:
- ASPHALT
- CONCRETE
- GRASS
- SAND
- GRAVEL, LIMESTONE
This data is used when working with AFM performance tables.
Other Influences on Take-off Distance
SLOPE
SLOPE gives the slope of the track, SLOPE is given in degrees or percentages, and found in the AD-Info part of the VFR-Manual, showing its altitudes and a drawing of the runway profile.
Other Influences on Take-off Distance
Runway Conditions
The RUNWAY CONDITIONS have a great influence on take-off and landing behaviour.
For estimating the feasibility of a take-off or a landing, the following information is available:
- SURFACE WET OR DRY
- STANDING WATER
- PATCHES OF SNOW AND ICE
- HIGH GRASS
- WET, SOFT FIELD
This information is displayed either by a personal visit prior to take-off, on RTF or ATIS, or by special announcements on SNOWTAM, indicating whether the runway is dry or wet, or if it is covered with snow (layer thickness), half-melted snow or ice and the BRAKING ACTION.
Use of take-off lift devices
FLAPS
FLAPS are used for take-off and landing to increase lift, and if required, the required positions and flight performance are Data in the AFM tables.
SLATS and SLOTS
The leading edge slats and slots are high-lift devices on the leading edge of the wing, and only a few basic airplanes are equipped with them. The procedures are described in the corresponding AFMS. The leading edge slats are used on most heavy aircraft to increase lift during take-off and landing.
Calculation of Wind Components
This calculation is a simple trigonometric exercise.
The solution lies in the use of a right-angled triangle: The head and cross wind components are cosine and sine functions respectively.
Caclculation of Wind Components
Rule of thumb:
For calculating the influence of headwinds and tail winds on a required length of the runway:
The headwind decreases the required runway length by 10% for each 9 KTS of intensity.
The tail wind increases the required runway length by 10% for each 2 KTS of intensity.