Knowledge Cards
Printable A6 quick-reference cards for the cockpit and flight bag. Click any card to preview and print.
Density Altitude
What It Is
Density Altitude = Pressure Altitude corrected for non-standard temperature.
High DA → thinner air → reduced lift, thrust & propeller efficiency.
Quick Formula
DA ≈ PA + 120 × (OAT − ISA temp)
ISA temp at altitude = 15°C − 2°C per 1000 ft PA
Example
| Value | |
|---|---|
| Airfield elevation | 1500 ft |
| QNH | 1005 hPa |
| OAT | +28°C |
| PA ≈ | 1500 + (1013−1005)×27 = 1716 ft |
| ISA at 1716 ft ≈ | 15 − 3.4 = 11.6°C |
| DA ≈ | 1716 + 120×(28−11.6) = 3685 ft |
Rules of Thumb
- DA > 5000 ft → expect noticeably longer T/O roll
- Hot & high = density altitude danger
- Check POH performance charts using DA, not elevation
EASA PPL Syllabus / ICAO Annex 8
Radio Phraseology
Standard Calls
| Phase | Pilot says |
|---|---|
| Initial call | [Station] [Callsign] [Position] [Level] [Request] |
| Read-back | Repeat all clearances, altimeter, and runway |
| Level report | “Passing [FL/ALT], climbing/descending [FL/ALT]” |
Key Words
WILCO — Will comply
ROGER — Received (no compliance implied)
AFFIRM / NEGATIVE — Yes / No
STANDBY — Wait, I will call you
SAY AGAIN — Please repeat
CORRECTION — Error, correct version follows
Distress & Urgency
| Prefix | Condition | |
|---|---|---|
| Distress | MAYDAY × 3 | Grave & imminent danger |
| Urgency | PAN-PAN × 3 | Urgent, not immediate danger |
Both on 121.500 MHz if no contact.
Frequency Change
“Changing to [freq], [callsign]”
New station: “[Station] [Callsign] [level] [request]”
ICAO Doc 9835 / EU No 923/2012
VFR Weather Minima
Controlled Airspace (Class C–E)
| Visibility | Cloud distance |
|---|---|
| 5 km | 1500 m horizontal |
| 300 m (1000 ft) vertical |
Uncontrolled (Class F/G)
At or above 3000 ft AMSL / 1000 ft AGL (whichever higher)
| Visibility | Cloud distance |
|---|---|
| 5 km | 1500 m horizontal |
| 300 m (1000 ft) vertical |
Below 3000 ft AMSL and below 1000 ft AGL
| Visibility | Cloud |
|---|---|
| 1500 m | Clear of cloud, surface in sight |
Special VFR
- Visibility ≥ 1500 m
- Clear of cloud
- ATC clearance required
SERA.5001 / EU No 923/2012