Runway Markings

runway

The Precision Approach Path Indicator (PAPI)

The Precision Approach Path Indicator (PAPI) is the commonly used glidepath system. It provides the glidepath information required during approaches. It is usually found on the left side of the runway and consists of a single row of lights. The glidepath is normally set at 3 degrees.

In a typical system (see the figure shown above) a single row concicting of 4 light units projects the following colours based on the visual approach path:

• If the aircraft is below the glidepath, all 4 lights are red.
• If the aircraft is above the glidepath, all 4 lights are white.
• If the aircraft is on the glidepath, the PAPI projects 2 red and 2 white lights.

The International Phonetic alphabet

V-speeds defined

V-speeds are used to define the airspeeds of an aircraft during all stages of its flight.

• VS --> Stalling speed or the minimum steady flight speed at which the airplane is controllable.
• VMCG --> Minimum control speed on the ground, with one engine inoperative, (critical engine on two engine airplanes) takeoff power on other engine(s), using aerodynamic controls only for directional control. (Must be less than V1).
• VMCA --> Minimum control speed in the air, with one engine inoperative, (critical engine on two engine airplanes) operating engine(s) at take off power, maximum of 5° bank into the good engine(s).
• V1 --> Critical engine failure speed or decision speed. Engine failure below this speed shall result in an aborted takeoff; above this speed the take off run should be continued.
• VR --> Speed at which the rotation of the airplane is initiated to takeoff attitude. This speed cannot be less than V1 or less than 1.05 times VMC. With an engine failure, it must also allow for the acceleration to V2 at the 35-foot height at the end of the runway.
• VLO --> Lift-off speed. The speed at which the airplane first becomes airborne.
• V2 --> The takeoff safety speed which must be attained at the 35-foot height at the end of the required runway distance. This is essentially the best one-engine inoperative angle of climb speed for the airplane and should be held until clearing obstacles after takeoff, or until at least 400 feet above the ground.
• VFS --> Final segment climb speed, which is based upon one-engine inoperative climb, clean configuration, and maximum continuous power setting.