Operational Procedures — Page 43, Lesson 60

I want to walk you through the planning minima for ETOPS en route alternates and the rules the commander must follow before take-off and approach. First, let's talk about the special case of an isolated destination. If the destination is so isolated that no useable diversion aerodrome exists, that's the only time you'd be in a situation where you have no alternate at all — but that's the exception, not the rule. Now, for ETOPS — Extended-range Twin-engine Operations — you need specific en route alternate aerodromes. An operator shall only select an aerodrome as an ETOPS en route alternate aerodrome when the appropriate weather reports or forecasts, or any combination thereof, indicate that, between the anticipated time of landing until one hour after the latest possible time of landing, conditions calculated by adding the additional limits of Figure 4.2 will exist. Let me break that down. You're looking at the weather from the time you expect to land, all the way through to one hour after the latest possible time you could land. That's a window of at least one hour after your latest landing time. And the conditions must be at or above the values you get by adding the increments from Figure 4.2 to the normal approach minima. Figure 4.2 gives us two categories. For a precision approach procedure — that's an approach with vertical guidance like an ILS — the alternate airfield ceiling is your authorized DH or DA, that's Decision Height or Decision Altitude, plus an increment of 200 feet. And the visibility or RVR — Runway Visual Range — is your authorized visibility plus an increment of 800 metres. For a non-precision approach or a circling approach — where you don't have full vertical guidance — the alternate airfield ceiling is your authorized MDH or MDA, that's Minimum Descent Height or Minimum Descent Altitude, plus an increment of 400 feet. And the visibility or RVR is your authorized visibility plus an increment of 1500 metres. The operator must also include in the Operations Manual, the OM, the method for determining the operating minima at the planned ETOPS en route alternate aerodrome. So the company has to document exactly how they calculate those minima. Now, moving on to the general rules for the commander. For an IFR flight — Instrument Flight Rules — the commander shall only commence take-off or continue beyond the point from which a revised flight plan applies in the event of in-flight re-planning, when information is available indicating that the expected weather conditions at ETA — Estimated Time of Arrival — at the destination and/or required alternate aerodromes, are at or above the planning minima. So before you even start the take-off roll, or if you have to re-plan in the air and go past a certain point, you need to know that the weather at your destination and any required alternates is forecast to be at or above the planning minima at your estimated time of arrival. Additionally, on an IFR flight, the commander shall only continue towards the planned destination aerodrome when the latest information available indicates that at ETA the weather conditions at the destination or at least one destination alternate are at or above the applicable aerodrome operating minima. So you can keep going to your destination only if the latest weather report or forecast shows that either the destination itself or at least one alternate has weather at or above the minima. For a VFR flight — Visual Flight Rules — the commander will only commence the flight when the weather reports or forecasts indicate that the meteorological conditions along the route, or the part of the route to be flown under VFR, will permit flight under VFR. So for VFR, you're not looking at minima in the same way — you need to know that the weather along your entire intended route, or at least the portion you'll fly under VFR, will actually allow you to stay in visual conditions. Finally, let's look at approach and landing conditions. Before commencing any approach to land, the commander is to be satisfied that according to the information available, the weather at the aerodrome and the condition of the runway to be used will not prevent a safe approach, landing or missed approach being made in accordance with the performance information in the Operations Manual. So before you start descending towards the runway, you must check the current weather and the runway condition — things like braking action, contamination, or surface state — and confirm that a safe approach, landing, or if needed a missed approach, can be flown using the performance data your company has published in the OM.