Flight plans & comms failure

010 Air LawChapter 4

Schematic

Repetitive FPL for regular routes; individual for one-off; modification before departure or in flight as required.

When to file a flight plan

Key fact

FPL required for: IFR in controlled airspace; VFR crossing international boundaries; flights in advisory airspace (Class F) where prescribed; search and rescue coverage requested.

Key fact

Submit at least 60 minutes before departure (or as per local AIP). Repetitive FPL (RPL) — same route/schedule; valid minimum 24 hours in advance.

FPL contents (key fields)

Field	Content
7	Aircraft identification
9	Number, type, wake category
13	Departure aerodrome + time
15	Route + cruising speed/level
16	Destination + EET + alternate
18	Other information (PBN, NAV/COM, etc.)

Key fact

Closing FPL — notify ATC on landing if no arrival message expected. Delay >30 min — inform ATS. Cancel before departure if flight not operating.

Schematic

MAYDAY = grave and imminent danger. PAN PAN = urgency — safety of aircraft or person not yet in distress.

Distress and urgency

Key fact

MAYDAY — distress: grave and imminent danger requiring immediate assistance. Repeat 3 times; state aircraft ID, nature of emergency, intentions, position, level, crew/passengers, fuel endurance.

Key fact

PAN PAN — urgency: safety of aircraft or person on board or elsewhere but not yet in distress. Repeat 3 times.

Key fact

Distress message has absolute priority over all other communications. All stations cease transmitting on the frequency.

Radio communication failure

Key fact

7600 — squawk immediately. VFR — continue VFR, land at nearest suitable aerodrome, report arrival. IFR — proceed to assigned or expected route/level; if neither, filed route and level; land at estimated time of arrival (±3 min window at controlled aerodromes).

Exam trap

7600 vs 7700 — 7700 is emergency (may still have comms). 7600 is radio failure specifically. Do not confuse with hijack (7500).

Emergency equipment

Key fact

ELT — transmits on 121.5 MHz and 406 MHz. 406 MHz satellite detection. 121.5 MHz homing only (monitoring reduced — not primary alert).