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Meteorology

A cap cloud forms on the windward side of the mountain, covering the

mountaintop and extending down the leeward side like a waterfall.

This cloud type is dangerous because it covers the mountaintop, and there are

strong downdrafts on the leeward side (up to 5000 feet per minute).

These winds are the reason the air is not sufficiently heated (adiabatically) and

thus, the clouds do not dissipate before reaching the valley floor.

Good advice when mountain flying:

- Avoid flying over mountains from the leeward side at low altitude; climb to

3000 feet above the mountain height 100 km before the mountain.

- Approach the mountain range at an angle of no more than 45 degrees so

that you can turn around if you detect mountain waves on the leeward side.

- Avoid flying through mountain passes in strong wind conditions.

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3.9.7 Runway condition

The runway may be wet, snow-covered, or ice-coated, etc. In such cases, it's

useful to know where you can get information about the runway condition

before landing.

3.9.7.1 Runway Condition Report (RCR)

At larger airports:

1. The airport operator assesses the runway surface condition.

2. The runway condition code (RWYCC) is established.

3. The result is communicated in a runway condition report (RCR).

The standard used is GRF (Global Reporting Format).

The Global Reporting Format was developed by ICAO in 2021 to standardize

and simplify the reporting of runway and weather conditions at airports.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© marts 2026 335