Between 120 and 180 minutes without ETOPS
The 180-minute allowance for smaller turbojets is not ETOPS, but it is bought with similar coin. The rule demands evidence for the approval: established flight planning and dispatch procedures, and specific maintenance instructions in the aircraft maintenance programme including an engine oil consumption programme and an engine condition monitoring programme. The acceptable means of compliance then fills the frame: the aeroplane should be certified to CS-25 or equivalent, engine events such as shutdowns, flameouts and unscheduled removals should be reported to the type certificate holders and the authority and evaluated, the minimum equipment list should name what has to be serviceable for this regime, and the operator should run a pre-departure check of the significant systems, described in the operations manual, over and above the ordinary pre-flight inspection. The guidance sketches what significant means: propulsion and any system whose failure could adversely affect the safety of the diversion, from electrics and hydraulics to fire detection.
Flight crew training should lean on the long diversion: fuel management with an independent cross-check of the fuel quantity indications, go/no-go and diversion decision-making with constant awareness of the closest weather-permissible alternate in terms of time, one-engine-inoperative drift-down and service ceiling data, and in-flight weather updates for the en-route alternate, destination and destination alternate. Dispatch should price the critical fuel scenario: an engine and the cabin pressurisation failing simultaneously at the most critical point of the route, followed by a diversion flown at 10,000 ft, or at 25,000 ft or the single-engine ceiling, whichever is lower, if oxygen can supply every occupant for the run; then a descent and 15-minute hold at 1,500 ft, descent to the applicable MDA/DH with the complete missed approach, and a normal approach and landing. If the scenario, priced for the worse case of one engine or two engines running, costs more than the ordinary fuel scheme carries, the difference goes in the tanks, with allowances for ice protection and any APU use on top. And the operator should ensure en-route alternates are available for the route within the 180-minute distance at the approved speed, with weather checked against the aerodrome selection rules of the previous lesson.
The ETOPS approval
Beyond the threshold distance of the fence, the rule of Part-SPA is absolute: in commercial air transport, two-engined aeroplanes shall only be operated there if the operator has been granted an ETOPS operational approval by the competent authority. The syllabus point that ETOPS approval is part of an AOC is this machinery seen from the certificate's side: the approval is entered in the operations specifications, the document the AOC lesson attached to the certificate.
To obtain the approval, the operator shall provide evidence on four fronts:
The machine — the aeroplane and engine combination holds an ETOPS type design and reliability approval for the intended operation.
The people — a training programme exists for flight crew and all other operations personnel involved, and they are suitably qualified.
The organisation — the operator's organisation and experience are appropriate to support the operation.
The procedures — operating procedures have been established.
The guidance points to AMC 20-6 for the detailed approval criteria. Notice the shape: airworthiness approval of the type is necessary but not sufficient, the operator itself is approved, which is why one airline may fly a route that an identical aeroplane in other colours may not.
Alternates for the ETOPS flight
The take-off alternate carries over from the previous lesson with the ETOPS twist already built in: the approved diversion time, subject to any MEL restriction, up to a maximum of 2 hours at the one-engine-inoperative cruising speed, against the plain twin's 1 hour and the three- or four-engined aeroplane's 2 all-engines hours.
The heart of the regime is the ETOPS en-route alternate. The rule defines its adequacy on its own terms: the aerodrome is adequate if, at the expected time of use, it is available and equipped with the necessary ancillary services, air traffic services, sufficient lighting, communications, weather reporting, navigation aids and emergency services, and has at least one instrument approach procedure available. Prior to conducting an ETOPS flight, the operator shall ensure that such an alternate is available within either the operator's approved diversion time or a diversion time based on the MEL-generated serviceability status of the aeroplane, whichever is shorter. The required alternates shall be specified in both the operational flight plan and the ATS flight plan.
Weather at the ETOPS en-route alternate is judged by its own clock and its own table, and both are rule-level. The window runs from the anticipated time of landing until 1 hour after the latest possible time of landing, not the hour-either-side window of the ordinary selection policy. The planning minima are built by adding margins to the aerodrome's figures: for a precision approach, DA/H plus 200 ft and RVR or visibility plus 800 m; for a non-precision or circling approach, MDA/H plus 400 ft and RVR or visibility plus 1,500 m. The additions are the same numbers the flight-preparation lesson's planning-minima table used, but this is a different rule wearing them: that table was an acceptable means keyed to type A and type B operations, this one is a regulation keyed to precision and non-precision vocabulary, judged over the longer window. The operator shall also include in the operations manual its method for determining the operating minima at the planned ETOPS en-route alternate.