ETOPS (Extended-range Twin-engine Operational Performance Standards) are regulatory norms that allow twin-engine airplanes to fly routes that may be a certain flight time away from the nearest suitable airport.

These standards were developed to ensure flight safety over remote regions such as oceans, deserts, or ice caps. ETOPS enables the use of shorter and more economical routes, reducing fuel consumption and flight time.

The history of ETOPS began in the 1980s when the FAA decided to allow twin-engine airplanes to fly routes that exceeded the standard flight restrictions of 60 minutes from the nearest airport.

Over time, as the reliability of engines and aircraft systems improved, the limits of ETOPS were expanded, reaching 120, 180, and in some cases even 240 minutes of flight time from the nearest airport. Airlines began to use more efficient and reliable twin-engine airplanes for long-haul flights.

Previously, international flights were primarily operated by four-engine airplanes. ETOPS changed the game, allowing twin-engine aircraft like the Boeing 777 or Airbus A330 to safely perform transcontinental and transoceanic flights.

A distinctive feature of ETOPS is that it requires airlines to strictly adhere to maintenance procedures and readiness for emergency situations, especially for flights over water where landing options are limited.

For example, crossing the Atlantic or Pacific Oceans, airplanes must meet stricter ETOPS requirements to ensure safety in case of emergencies.

To conduct ETOPS flights, airlines and their aircraft must meet a series of stringent requirements. These include specialized crew training, specific emergency equipment, communication and navigation systems, as well as requirements for aircraft maintenance and checks.

These measures are aimed at ensuring flight safety in the event of one engine failure or other issues far from suitable airports.

ETOPS Certification

To obtain ETOPS certification, airlines and their aircraft must meet a number of strict criteria. These include:

Meeting these requirements ensures that even in the event of a critical emergency situation, the aircraft can safely fly to the nearest airport.

Important ETOPS Definitions

Given the strict compliance criteria of ETOPS, it is crucial to highlight the most important aspects in planning and conducting flights. For instance, in selecting alternate airports, two terms are used as guidelines: suitable and adequate airports.

Conditions for choosing an Adequate Airport include:

• Availability (no restrictions on service due to NOTAM, and the airport is open during the expected flight time);
• Permission for flight over the airport and landing there;
• Availability of ground services (ATC, meteorological, etc.);
• Availability of navigational aids, such as ILS, VOR, NDB, for an instrument approach (at least one must be available);
• Firefighting services (RFF) at least ICAO Category 4, and if located outside the airport, within 30 minutes' reach from notification;
• Availability of technical and ground services, as well as catering (including refueling);
• Capability to accommodate and service passengers.

Operational Period = within one hour before and one hour after the expected time of arrival (ETA).

What other requirements must be met?

• The forecast of crosswind strength must also meet the aircraft's takeoff and landing performance limitations throughout the operational period, as well as runway surface conditions. NOTAMs and SNOWTAMs must also ensure landing requirements when choosing it as an alternate.
• The maximum Diversion Time is the time required to reach any Adequate Airport beyond a distance exceeding one hour of flight. It can be up to 120 minutes, depending on the authorization granted to the carrier and the aircraft.

For ETOPS flights, the speed and distance set by the operator necessary for flight on one engine to an alternate airport are determined. For instance, for a Boeing 737-800, this speed is 280 knots, or 0.76M, implying that the speed is between the minimum clean wing flight speed (VFE) and the maximum flight speed (VMO/MMO).

Selecting this speed is necessary both for ensuring the established range and for calculating the critical fuel scenario.

Key Points in ETOPS Flight Segment

ETOPS Entry Point (EEP) - a point on the flight route no more than one hour of single-engine flight time from a selected alternate airport.

ETOPS Exit Point (EXP) - the exit point from the ETOPS segment.

ETOPS Segment - a segment of the route located between EEP (ETOPS Entry Point) and EXP (ETOPS Exit Point).

Equal Time Point (ETP) - a point on the ETOPS route that is equidistant from EEP and EXP when deciding to divert to an en-route alternate airport. This means the flight time to the nearest alternates is equal.

This point is determined by the flight plan (OFP), and there may be several such points throughout the flight.

When calculating the flight plan, it must be indicated that the flight consists of ETOPS segments. There may also be several such segments. However, the OFP must contain a line about the time applied to ETOPS flight (90 or 120 minutes).

What are the requirements for the aircraft?

ETOPS Configuration - requirements for the technical condition of the aircraft, including special MEL (Minimum Equipment List) limitations, ground service, and crew actions during pre-flight preparation and in flight.

The operator must provide requirements for the aircraft configuration in any convenient form, indicating the systems whose presence and functioning are necessary before starting a flight in the ETOPS segment.

In the MEL list of permissible defects, the following remarks are mandatory:

• For ER operations, or
• Except for ER operations.

The crew, during pre-flight checks, ensures that the aircraft is ready, including checking the amount of oil and its consumption in flight, the normal operation of the fuel system, operation of the auxiliary power unit (APU), and checks the fire extinguishing and detection systems.

Crew Requirements

Before performing the flight, all crew members must have the corresponding approval for ETOPS flight, issued after completing the appropriate ground and simulator training.

In flight, the crew performs the prescribed procedure upon entering the ETOPS segment, which may differ depending on the operator, but at a minimum (mandatory), checks the operability and subsequent activation of the APU generator throughout the flight in the ETOPS segment. Otherwise, entry into the zone is prohibited.

The crew before the flight must ensure that the OFP reflects and complies with the following requirements:

• Alternate airports along the route, meeting the ETOPS requirements, are specified;
• Additional fuel required for APU operation in flight is added;
• The flight plan contains EEP, ETP, and EXP points;
• The flight plan meets the 90/120-minute rule requirements for ETOPS;
• The flight plan includes a calculation of the critical fuel scenario.

Today, ETOPS flights have become the norm for many international airlines. They have significantly increased efficiency and reduced the cost of international air transport. Statistics show that most transoceanic and many transcontinental flights are now conducted using ETOPS standards, ensuring safety and comfort for passengers on these routes.

Name of article: ETOPS flights
Release date: 12/28/2023
Acrticle author: Georgii Kurbatskii