Page 330 - PPL-engelsk 2025

Meteorology

The need to issue SIGMET regarding thunderstorms includes

situations where:

- there is an area of widespread CB activity with severe weather
phenomena, e.g. in connection with unstable low pressure

- (TS = thunder storm)

- CB is found along a line with little or no separation, e.g. in

connection with a cold front. (FRQ = non separated CB).

- CB is found completely surrounded by another cloud layer, e.g. in

warm front clouds (EMBD = embedded (= hidden CB clouds)).

- CB is found completely surrounded by haze layers, e.g. in
connection with thermal thunderstorms (OBSC = obscured (= CB

clouds hidden in haze)).

3.9.5 Weather phenomena resulting from thunderstorms

The greatest danger associated with thunderstorms is the other weather

phenomena that accompany them, such as lightning, hail, turbulence, and ice

formation.

3.9.5.1 Lightning

When an aircraft is struck by lightning, only a limited electrical effect is

transmitted. You can usually see where the charge entered the aircraft's body

or propeller.

The energy is conducted through the aircraft's outer structure, and it is usually

possible to see where the lightning exited the plane.

Electrical components may be damaged. If it is night, you should turn on the

cockpit lighting to avoid being blinded by the lightning.

3.9.5.2 Hail

Hail begins as a small "bandit" about 5 mm in size.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 330