Aeroplane Equipment and Instruments — Page 86, Lesson 134

I want to walk you through the equipment and instruments that must be carried on aeroplanes, starting with life-saving equipment for overwater flights. Let's begin with life jackets. For flights that do not go over the sea, there is no requirement to carry them. But when an aeroplane does fly over water, it must be fitted with one life jacket — or an equivalent individual flotation device — for every person on board. Each life jacket or flotation device must be stowed in a position that is easily accessible from the seat of the person it is intended for. And every single one of them must be equipped with a location light, so that a person in the water can be seen at night or in low visibility. Now, let's move to long-range overwater flights. An operator cannot fly an aeroplane over water at a distance from land — where an emergency landing would be possible — that exceeds a certain limit. That limit depends on the aeroplane's capability. For aeroplanes that can continue flying to an aerodrome even if the critical power unit fails at any point along the route or on a planned diversion, the maximum distance from land is the lesser of 120 minutes at cruising speed or 400 nautical miles. So whichever of those two numbers is smaller becomes the limit. For all other aeroplanes — those that cannot guarantee continued flight after a critical engine failure — the limit is much tighter: the lesser of 30 minutes at cruising speed or 100 nautical miles. If an operator wants to fly beyond those limits, they must carry the equipment specified in subparagraphs (a) and (b). Let me go through those. Subparagraph (a) requires sufficient life-rafts to carry all persons on board. And there is a specific rule about redundancy: unless you carry extra rafts with enough capacity, the buoyancy and seating capacity beyond the rated capacity of the rafts must be enough to accommodate all occupants even if you lose one raft of the largest rated capacity. In other words, if the biggest raft fails, the remaining rafts must still hold everyone. Each life-raft must be equipped with a survivor locator light — that's a light to help rescuers find the raft — and life-saving equipment including means of sustaining life, appropriate to the flight being undertaken. Subparagraph (b) requires at least two survival emergency locator transmitters, or ELTs. These must be capable of transmitting on 121.5 megahertz and 406 kilohertz. These are the international distress frequencies that search and rescue services monitor. Next, let's talk about weather radar. When an aeroplane carries passengers and is pressurized, it must be fitted with a serviceable weather radar whenever it is operated in areas where thunderstorms or other potentially hazardous weather conditions — that can be detected by airborne weather radar — are expected along the route. EU-OPS expands this requirement further: it also applies to unpressurized aeroplanes with a maximum take-off mass, or MTOM, greater than 5700 kilograms, and to any unpressurized aeroplane with more than 9 passenger seats. However, for propeller-driven pressurized aeroplanes with an MTOM not exceeding 5700 kilograms and not more than 9 passenger seats, a suitable system for detecting thunderstorms and other potentially hazardous conditions may be used instead of radar. So a smaller pressurized turboprop, for example, could use an alternative detection system rather than full weather radar. Now, equipment for operations in icing conditions. Aeroplanes are not allowed to be operated in expected or actual icing conditions unless they are certified and equipped for flight in icing conditions. That is a hard rule. Additionally, when operating at night in such conditions, the aeroplane must be equipped with an ice detection device, or a method of illumination that allows the crew to detect ice formation on the airframe. Finally, the Machmeter. Any aeroplane whose speed limitations are expressed in terms of Mach number — that is, a limiting Mach — must be equipped with a Mach number indicator, which we call a Machmeter. This does not prevent you from also using the airspeed indicator to derive Mach number for air traffic services purposes, but the dedicated Machmeter is required when the aeroplane has a limiting Mach. That covers the key equipment requirements for overwater flights, weather radar, icing operations, and Machmeters.