Keep that in mind as the context for everything that follows — Page 111, Lesson 174

Let’s start with the very first line, because it’s a classic exam trap. That opening sentence — “This serves to warn all personnel that the engines may be started” — is the purpose of a specific signal, and it belongs to the rule just before our excerpt, which is about the use of flashing lights on the ground. So when you see a flashing light on an aircraft while it’s on the apron, that’s the warning: engines may be started at any moment. Keep that in mind as the context for everything that follows. Now, 6.26 — Anti-collision Lights. The rule is precise: all aircraft in flight which are fitted with anti-collision lights shall display the lights by day as well as by night. So the moment you’re in flight, if the aircraft has anti-collision lights installed, they must be on — day and night. The excerpt adds an important clarification: this is in addition to 6.23, bullet point 1. That earlier rule is the one that requires certain aircraft to carry anti-collision lights by law. This rule, 6.26, is the catch-all: even if your aircraft is fitted with anti-collision lights but they are not specifically required by law, you still have to illuminate them by day and by night. So the legal requirement to display them is broader than the legal requirement to fit them. Next, 6.27 — Safety. This is the one permitted exception. A pilot is allowed to switch off or reduce the intensity of any flashing lights if they are likely to adversely affect the satisfactory performance of duties, or if they would subject an outside observer to harmful dazzle. So the law gives you discretion: if the flashing is genuinely interfering with your ability to do your job, or blinding someone on the ground, you may dim or extinguish them. But note the wording — it’s a permission, not a blanket right; the condition is that the light is likely to cause that harm. Now we move to 6.28 — Simulated IMC. This is a big one, and I want you to hold the definition exactly. Simulated IMC is defined as: reducing the forward visibility of the Pilot Flying (PF) so that he or she has to rely on instruments for attitude and other flight data. So the PF — that’s the pilot actually controlling the aircraft — is deliberately deprived of forward vision, forcing them to fly purely on instruments. That’s the whole point: it’s a training exercise to practice instrument flying. How do you achieve it? Two methods are given. First, by the use of full or partial flight deck window screens to prevent forward visibility. Second, by the use of a visor to ‘blinker’ the pilot — that’s the term used, to restrict their view like blinkers on a horse. Now, the most important factor, and I want you to underline this mentally: simulated IMC can only be carried out in VMC — Visual Meteorological Conditions. That’s the critical constraint. The requirements that follow exist precisely to make sure you comply with VFR — Visual Flight Rules — while the PF’s visibility is impaired and they cannot maintain the lookout that the law requires. So the whole structure of this rule is about protecting the safety of the flight while one pilot is effectively blind to the outside world. Let’s go through the requirements one by one, because they’re all examinable. First: An aircraft shall not be flown under simulated IMC unless — and here come the conditions. Condition one: Fully functioning dual controls are fitted. So the aircraft must have a complete, working set of controls on both sides — the safety pilot must be able to take control at any moment. Condition two: A qualified pilot (need not be type rated) occupies a control seat to act as safety pilot (PNF). So the safety pilot is the PNF — the Pilot Not Flying. They must be a qualified pilot, but note the qualifier: they do not need to be type rated on that specific aircraft. They just need to be a qualified pilot, sitting in a control seat. Condition three: The safety pilot must have adequate forward vision and to each side of the aircraft. So the safety pilot’s view must cover forward and both sides. But here’s the fallback: If not, then a competent observer must be used. And the excerpt gives you the exact requirements for that observer — they must know what an aeroplane in flight looks like, be able to report any airborne contact clearly and concisely, and be able to use the internal communications system of the aeroplane. That observer must occupy a position in the aircraft from which they have a field of vision that adequately supplements that of the safety pilot, and they must be in communication with the safety pilot. So the logic is: the safety pilot is your primary lookout, but if their view is inadequate, you bring in a competent observer to fill the gaps, and that observer must be able to talk to the safety pilot. Let me tie it all together for you. The theme of this whole excerpt is visibility and safety. On the ground, flashing lights warn that engines may start. In flight, anti-collision lights must be on day and night to make the aircraft visible. And when we deliberately blind the PF for training, we build a whole safety net — dual controls, a qualified safety pilot, and if needed a competent observer — to make sure the aircraft remains visible and controllable. That’s the thread. One more time on the key numbers and terms you must own: anti-collision lights — day and night, in flight, whether or not legally required to be fitted. Flashing lights — may be switched off or dimmed if they harm performance or dazzle observers. Simulated IMC — reducing PF forward visibility to force instrument reliance. Only in VMC. Dual controls — fully functioning. Safety pilot — qualified, not necessarily type rated, in a control seat, with adequate forward and side vision. Competent observer — knows what an aeroplane in flight looks like, can report airborne contact clearly and concisely, can use the internal comms, positioned to supplement the safety pilot’s field of vision, in communication with the safety pilot. That’s the complete picture. Take a moment to let it settle, and when you’re ready, we’ll move on.