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March 26, 2018
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ETOPS (Extended Twin Engine Operations)

What is ETOPS (Extended Twin Engine Operations)?


You should have heard the word ETOPS, which is extensively used the field of aviation. ETOPS is the acronym for Extended Twin Engine Operations. This is a special operation intended for twin-engine aircraft to utilize them in extended operations. Normally extended routes lie over oceanic regions. Using twin-engine aircraft for these routes pose a threat to the safety of the passengers and the aircraft. If one engine fails due to any reason the aircraft has to fly to an airport with the remaining engine. Lives of passengers and crew utterly depend on the remaining engine until the aircraft comes to a stop in the runway. Hence the integrity of critical aircraft components of twin-engine aircraft should be certified.


An ETOPS certified aircraft should undergo specific inspections, checks and maintenance activities to uplift its airworthiness. Prior to each departure, ETOPS aircraft undergo inspections outlined in a specific checklist to ensure its safety. A concept called Split maintenance is incorporated to inspect a maintenance activity that has been carried out in an ETOPS certified aircraft. A duplicate inspection is carried out to identify hidden flaws in a maintenance task in the split maintenance philosophy. All the systems and components which are mandated by the Minimum Equipment List (MEL) for Extended Range (ER) will be considered as ETOPS significant items.


Oil consumption programs, Engine condition monitoring, and Reliability programs are conducted on ETOPS aircraft to identify and prevent imminent failures.


An ETOPS Verification Flight has to be carried out to identify, rectify, verify and certify the ETOPS significant items before next ETOPS flight. A verification flight will be required for following occurrences,


  • Reported a defect in an ETOPS significant item and the defect can’t be reproduced or it can’t be tested 100% on the ground.
  • Occurring of intermittent failures and no means to verify the fault has been rectified through maintenance.
  • Maintenance in multiple ETOPS significant items.
  • Engine fuel or oil system component change.
  • When the aircraft was released from a letter “A” check and its multiples.


A verification flight should fly at least for 60 minutes and it can be a NON-ETOPS revenue flight, first 60 minutes of an ETOPS flight under the 60 minutes rule or a non-revenue verification flight.


60 minutes rule – Within first 60 minutes of the ETOPS flight, all the systems related to ETOPS should be verified as serviceable before entering the ETOPS sector.


An ETOPS Proving Flight has to be carried out for following occurrences,


  • In-Flight Shut Down of an engine (IFSD).
  • After undergoing a “C” check.
  • An engine change, removal, and reinstallation for gaining access.
  • Drop in fixed crew oxygen system pressure.


A proving flight has to conduct for the particular ETOPS diversion of the aircraft and it can be a NO-ETOPS revenue flight or a non-revenue flight.


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