Essential Aviation Procedures for Oceanic Flights

Posted on Sep 3, 2025 in Other subjects

ETOPS Regulations and Requirements

  • 60 minutes at cruising speed with One Engine Inoperative (OEI).
  • 180-minute rule: 180 minutes with OEI.

Non-ETOPS Operations

  • Class A Aircraft (over 45 tons / 20 MOPSC): 60 minutes OEI from the nearest suitable airport.
  • Class A Aircraft (under 45 tons / 20 MOPSC), Class B & C Aircraft: 120 minutes or 300 nautical miles OEI, whichever is less.

En-Route ETOPS Alternate Aerodrome Minima

Approach Type Minima

  • Precision Approach: Decision Altitude/Height (DA/H) + 200 feet, Runway Visual Range (RVR)/Visibility (VIS) + 800 meters.
  • Non-Precision/Circling Approach: Minimum Descent Altitude/Height (MDA/H) + 400 feet, RVR/VIS + 1500 meters.
  • Flight commencement is permitted when forecasts indicate that conditions at or above planning minima will exist at the estimated time of arrival or 1 hour thereafter.

Longitudinal Separation Standards

Turbojet Aircraft Separation

  • 15 minutes for aircraft on the same track and at the same Mach number.
  • 10 minutes if the Mach number technique is utilized.
  • 5 minutes absolute minimum, typically when the leading aircraft maintains a higher speed.

Turboprop Aircraft Separation

  • 20 minutes.
  • 30 minutes in the western area of the North Atlantic Tracks (NATs).

Lateral Separation Standards

  • Standard: 60 nautical miles (NM).
  • Absolute Minimum: 30 nautical miles (NM).

Cross-Track Difference Calculation

The cross-track difference can be calculated using the formula: (Conversion Angle x Distance / Departure) ÷ 230.

GTAP and TGAP: Navigation Protection

GTAP NH: Global Track Angle Protection for the Northern Hemisphere.
TGAP SH: Track Guidance Angle Protection for the Southern Hemisphere.

Flight Planning for Intercontinental NAT Flights

Flight plans for intercontinental flights operating within the North Atlantic Tracks (NAT) airspace must be filed 3 hours prior to engine start-up.

Reduced Vertical Separation Minima (RVSM)

  • 60 nautical miles lateral and 1000 feet vertical separation.
  • Applicable between Flight Level (FL) 290 and FL 410.
  • Vertical speed not exceeding 1500 feet per minute.
  • Pre-flight altimetry accuracy check required to be within 75 feet.
  • Overshoot/undershoot tolerance: 150 feet.
  • Primary altimeter cross-check difference not to exceed 200 feet.

RVSM Emergency and Contingency Procedures (Without ATC Clearance)

  • Engine Failure: Fly offset 15 nautical miles left or right of the cleared track.
  • At FL410: Climb 1000 feet or descend 500 feet, then turn left or right.
  • Within RVSM Airspace (below FL410): Climb or descend 500 feet.
  • Above FL140 (outside RVSM): Climb or descend 1000 feet.
  • Diversion without ATC Clearance: Offset 15 nautical miles.

North Atlantic (NAT) Airspace Procedures

  • Procedures are in accordance with ICAO Document 7030.
  • If VHF is out of range, use frequency 124.35 MHz.
  • Squawk code to be set 30 minutes after entering NAT airspace: 2000.
  • Squawk code to be set 40 minutes prior to entering NAT airspace: As requested by Air Traffic Control (ATC).
  • A revised estimate for the next position must be transmitted when the estimated time has changed by 3 minutes or more.
  • Tolerance boundary window for position reporting: 3 minutes.
  • Oceanic clearance must be requested 40 minutes prior to the oceanic entry point.
  • Instrument Flight Rules (IFR) apply when operating at or above FL60 or 2000 feet above ground level (AGL), whichever is greater.

Polar Track System

The Polar Track System is applicable in areas where the horizontal component of the magnetic field is less than 6 micro Teslas.

Minimum Navigation Performance Specification (MNPS)

MNPS Airspace Characteristics

  • Geographical extent: From 27° North to 90° North latitude.
  • Vertical separation: 1000 feet.
  • Lateral separation: 60 nautical miles between aircraft meeting MNPS requirements.
  • Equipment requirements: At least one Long Range Navigation System (LRNS) and at least two Inertial Navigation Units (INU).
  • Altitude range: Between Flight Level (FL) 285 and FL 420.

Westerly Headings and Flight Levels

For westerly headings, aircraft operate at even Flight Levels between FL 285 and FL 420.

Position Reporting Requirements

  • Every 20° of longitude when north of 70° North latitude.
  • Every 10° of longitude when south of 70° North latitude.

Long Range Navigation System (LRNS) Failures

  • LRNS Failure Before Flight: File special routes or operate above/below MNPS airspace.
  • Two LRNS Failures In-Flight: Only Track 9 (T9) can be used.
  • All LRNS Failures In-Flight: Climb or descend 500 feet.

Organized Track System (OTS)

  • Day (Westbound): 11:30 UTC to 19:00 UTC.
  • Night (Eastbound): 01:00 UTC to 08:00 UTC.
  • Out of Validity Period: 19:01 UTC – 00:59 UTC or 08:01 UTC – 11:29 UTC.

Non-MNPS Aircraft Operations

Non-MNPS approved aircraft can plan routes at Flight Level (FL) 280 or below.

Severe Weather Deviation Procedures

For deviations around severe weather, if the deviation is greater than 10 nautical miles, or the aircraft is 10 nautical miles from its cleared track, a level change of 300 feet is required.

  • Westbound: If deviating left, climb 300 feet; if deviating right, descend 300 feet.
  • Eastbound: If deviating left, descend 300 feet; if deviating right, climb 300 feet.