Aeroplane Equipment and Instruments — Page 86, Lesson 138

I want to walk you through the equipment and instrument requirements for aeroplanes, starting with the Audio Selector Panel, or ASP. An operator cannot operate an aeroplane under IFR — that's Instrument Flight Rules — unless it has an audio selector panel that is accessible to each required flight crew member. So if you have a two-pilot crew, both pilots need to be able to reach and use that panel. Now let's move to Navigation Equipment. The aeroplane must be fitted with navigation equipment that allows it to fly in accordance with its operational flight plan. That equipment also has to work within the limits specified for Required Navigation Performance, or RNP types, and as required by Air Traffic Control. The assumption here is that flights under VFR — Visual Flight Rules — are flown by visual reference to landmarks, so the navigation equipment requirements are different for IFR. For flights in areas where Minimum Navigation Performance Specifications, or MNPS, are specified, the aeroplane must be fitted with navigation equipment that continuously provides indications of adherence to, or departure from, track. It has to show, to the required degree of accuracy at any point along that track, whether you are staying on course or deviating. The MNPS and the procedures governing their application are published in a document called Regional Supplementary Procedures, which is Doc 7030. Now, for flights where Reduced Vertical Separation Minima, or RVSM, of 300 metres, which is 1000 feet, is applied between FL290 and FL410 — that's Flight Level 290 to Flight Level 410 — the aeroplane must be fitted with equipment that can do four things: first, indicate the flight level being flown; second, automatically maintain a selected flight level; third, provide an alert to the flight crew when a deviation occurs from the selected flight level — and the threshold for that alert shall not exceed plus or minus 90 metres, which is 300 feet; and fourth, automatically report pressure-altitude, which is Mode C. Let's move to Instrument Procedures. When an aeroplane is to be operated under IFR, or under VFR at night, it must be fitted with at least: VOR — that's VHF Omnidirectional Range; ADF — Automatic Direction Finder; and DME — Distance Measuring Equipment. Additionally, if flying in airspace that requires it, you also need an Area Navigation System and an Altitude Alerting SSR — Secondary Surveillance Radar. And if required for the intended approach, you need ILS — Instrument Landing System; MLS — Microwave Landing System; and a Marker Receiver. There's an important note here: the requirement for VOR, DME, and ADF is to be doubled where navigation is based on that aid alone. So if you are relying solely on VOR for navigation, you need two VOR receivers. Finally, let's talk about Installation. The equipment installation must be such that the failure of any single unit required for either communications or navigation purposes, or both, does not result in the failure of another unit required for communications or navigation purposes. In other words, if one radio or navigation receiver fails, it must not take out another one — they are independently installed so that a single failure doesn't leave you without both communication and navigation capability.