MRJT Additional Procedures — Page 114, Lesson 105

I want to walk you through the MRJT Additional Procedures, starting with some very specific definitions that the regulations use for ETOPS planning. These terms are precise and you need to know them exactly as written. First, Threshold Distance. This is the distance travelled in still air in 60 minutes by an aircraft at the normal one-engine-inoperative cruise speed. So think of it as a one-hour range figure under the assumption that you've lost an engine and are cruising at the speed you'd use in that situation, with no wind. It's a benchmark distance. Next, Rule Time. This is the maximum time that any point on the route may be from a suitable aerodrome for landing, as specified by the Authority and included in the operations manual. In other words, the regulator sets a time limit — say 120 minutes — and no point along your planned track can be farther than that time from a suitable airport, flying at the one-engine-inoperative speed. Then we have Rule Distance. That's simply the distance travelled in the rule time, at the normal one-engine-inoperative cruise speed. So if your rule time is 120 minutes and your one-engine-inoperative cruise speed gives you a certain distance per hour, the rule distance is how far you can go in that time. It's the geographic expression of the rule time. Now, two critical aerodrome classifications: Adequate Airfield and Suitable Airfield. They are not the same thing. An Adequate Airfield is one that the operator, in general terms, appraises as having long enough runways and sufficient equipment to be considered adequate for their planned ETOPS routes. In particular, at the anticipated time of use, two conditions must be met. First, the aerodrome will be available and equipped with the necessary ancillary services — that includes ATC, sufficient lighting, communications, weather reporting, navaids, and safety cover. Second, at least one let-down aid must be available for an instrument approach, and ground radar would qualify as such an aid. A Suitable Airfield is a step further. The commander — that's you, the pilot in command — must satisfy yourself on the day, using criteria provided by the operator, that you have sufficient adequate aerodromes which, taking into account the weather and any equipment unserviceabilities, are suitable for your intended operation. An aerodrome shall only be selected as an ETOPS enroute alternative 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 will be at or above the planning minima. So suitability is a real-time, day-of-operation judgment by the commander, based on weather and aircraft serviceability. Now let's move to ETOPS and the Minimum Equipment List, or MEL. The MEL is the document that tells you what equipment can be inoperative and still allow dispatch. For ETOPS, primary system redundancy levels appropriate to ETOPS will be reflected in the MEL. For aeroplanes in operational service, the existing MEL will be re-evaluated and adjusted as necessary to reflect the primary system redundancy levels required for ETOPS. What are primary airframe systems? These are systems which have a fundamental influence on flight safety and could be adversely affected by the shutdown of a power unit — meaning an engine. The excerpt gives a list of examples: Electrical/battery, Hydraulic, Pneumatic, Flight Instrumentation, Fuel, Flight Control, Ice Protection, Engine Start and Ignition, Propulsion System Instruments, Navigation and Communications, APUs — that's Auxiliary Power Units — Air Conditioning and Pressurization, Cargo Fire Suppression, Emergency Equipment, Engine Fire Detection and Extinguishing Systems, and any other equipment for ETOPS. So the MEL for an ETOPS aeroplane is specifically adjusted to ensure that these critical systems have the redundancy required for extended operations over water or remote areas.