NOTAM & re-planning

033 Flight PlanningChapter 8

NOTAMs alert crews to temporary changes. Re-planning covers track errors, wind changes, and remaining fuel calculations en route.

NOTAM types

Code	Meaning
NOTAMN	New NOTAM
NOTAMR	Replaces previous NOTAM
NOTAMC	Cancels previous NOTAM

Key notes also use NOTAM-N / R / C — same meanings.

Date, time and validity format

Key fact

Dates and times: YYMMDDHHMM — all times UTC.

TRZ / ZRT (Temporary Restricted Zone): valid from 30 minutes before sunrise to 30 minutes after sunset.

Common NOTAM abbreviations

Abbrev	Meaning
LO	Locator
SVC	Service
TEMPO	Temporarily
PN	Prior notice
LGT	Light
U/S	Unserviceable
NOSIG	No significant change

Key fact

ACC (Area Control Centre) is not part of the airport — do not confuse with aerodrome facilities. Customs and health formalities are found in the AIP, not NOTAM alone.

Standard equipment reference (NOTAM context)

Key fact

S — Standard equipment considered: VHF radios, VOR, ILS (per summary/GSPRM).

Track error and rejoin — 1 in 60

Formula — Track error (1 in 60 rule)

Track error (°) = Distance off track × 60 ÷ Distance flown

Key fact

For track errors, the pilot should adjust heading to regain track ASAP and report deviations to ATC.

NAM-based fuel replanning

Formula — Fuel for distance change

Additional fuel = (New NAM − Old NAM) × fuel consumption (kg/NAM or lb/NAM)

Formula — Fuel remaining en route

Fuel remaining ≈ [(Block − Taxi) ÷ ((100% + contingency %) ÷ 100) ÷ endurance × flight time left] + contingency

Key fact

If wind changes from headwind to tailwind, do not waste time recalculating spurious extra fuel — tailwind reduces fuel burn. Read whether the question asks for worst case or actual conditions.

INS drift and heading

Formula — INS drift correction

True track = True heading + INS drift

True heading = True track − INS drift

Flight plan amendment triggers (re-planning summary)

Key fact

Re-plan or amend when:

• TAS varies by more than 5% or Mach 0.01
• ETA changes by more than 2 minutes
• EOBT delay exceeds 30 min (controlled) or 60 min (uncontrolled)
• Callsign, departure, or destination changes — new FPL required
• Diversion to uncontrolled aerodrome — notify ATC within 30 minutes

Computer flight plan limitations

Key fact

Computer flight plans may not reflect latest NOTAM, weather reroutes, or ATC flow restrictions. Always cross-check NOTAM briefing before dispatch and after significant delay.

Exam trap

NOTAM times are UTC with format YYMMDDHHMM. TRZ daylight window is SR−30 min to SS+30 min — not 24 h unless NOTAM body says otherwise.

Centre tank failure replan (en-route)

Key fact

On centre pump failure with transfer to wings: calculate transferred fuel, subtract consumption since failure, then endurance left = remaining ÷ fuel flow. Include in re-plan if continuing to alternate.