Aeroplane Equipment and Instruments — Page 82, Lesson 132

I want to walk you through the requirements for standby horizon instruments, aeroplane lighting, and flights over water. Let's start with the standby horizon. For aeroplanes with a maximum certificated take-off mass — that's the certified maximum weight the aircraft is allowed to be at when it starts its take-off roll — in excess of 5700 kilograms, or having a maximum approved passenger seating configuration of more than nine seats, the regulations require an additional, standby, attitude indicator. You'll also hear this called an artificial horizon. This standby instrument must be capable of being used from either pilot's station, so both the captain and the first officer can see and use it. Now, let me break down the five specific requirements for this standby horizon. First, it must be powered continuously during normal operation. Then, after a total failure of the normal electrical generating system — meaning the main generators or alternators have stopped producing power — it must be powered from a source independent of that normal system. There must also be an indicator to show that it is on its own power, so the crew knows it has switched to its backup source. Second, it must provide reliable operation for a minimum of 30 minutes after total failure of the normal electrical generating system. That 30-minute figure takes into account other loads on the emergency power supply — like other emergency systems drawing from the same battery or backup generator — and also considers operational procedures, meaning how the crew manages the situation. Third, it must operate independently of any other attitude indicating system. It cannot rely on the same sensors, gyros, or data sources as the primary attitude indicators. It is its own standalone system. Fourth, it must be operative automatically after total failure of the normal electrical generating system. The crew does not have to manually switch it on or activate it — it comes on by itself when the main electrical system fails. Fifth, it must be appropriately illuminated during all phases of operation. There is an exception, though: for aeroplanes with a maximum certificated take-off mass of 5700 kilograms or less, already registered in a Member State on 1 April 1995, and equipped with a standby attitude indicator in the left-hand instrument panel, the illumination requirement does not apply in the same way. Let's move to aeroplane lighting. For flights by day, an aeroplane is not to be operated unless it is equipped with several items. First, a functioning anti-collision light system — that's the flashing red or white beacon and strobe lights that make the aircraft visible to others. Second, adequate lighting for all the aeroplane instruments and equipment essential to the safe operation of the aeroplane — you need to be able to read your instruments. Third, lighting to illuminate the passenger compartment. And fourth, a torch — a flashlight — readily accessible for each crew member station. So each pilot and any other crew member must have a flashlight they can reach easily. For night operations, all aeroplanes require additional lighting beyond what I just listed for daytime. This includes navigation or position lights — the red, green, and white lights on the wingtips and tail that show the aircraft's position and direction to other traffic — and two landing lights, which illuminate the runway and approach area. Now, flights over water. Regulations apply to flights over water when aircraft are considered to be vulnerable to ditching. Ditching means an intentional emergency landing on water. The regulation considers this vulnerability to apply in two situations. First, when the aircraft is more than 93 kilometres — that's 50 nautical miles — from shore. Second, when the take-off or approach path is over water. The latter case — the take-off or approach path over water — resulted from the crash of the Lockheed Electra into the Potomac River after take-off from Washington Domestic Airport, now called Ronald Reagan Airport. In that accident, many passengers drowned because there was no requirement at that time for life preservers. That crash drove the regulatory change requiring life-saving equipment for overwater operations during take-off and approach.