Let's begin with MDH — that stands for Minimum Descent Height — Page 269, Lesson 376

I want to walk you through the index entries starting from the letter M and into N. This is a reference tool, so each line points you to the page numbers where that topic is discussed in the book. Let's begin with MDH — that stands for Minimum Descent Height. You'll find it on pages 61 and 62. This is a critical altitude used during non-precision approaches; it's the lowest you can descend without having the required visual reference to continue. Next we have Measured Coefficient, referenced on pages 234 and 235. That term relates to performance calculations, likely involving engine or aerodynamic coefficients that are measured rather than assumed. Megaphones appear on pages 83, 86, and 205. These are the handheld or fixed public-address devices used for ground crew communication or passenger announcements on the apron. MEL is the Minimum Equipment List, and it's a big one — pages 45, 73, 134, 145, and 146. The MEL is the document that tells you which aircraft systems may be inoperative for a flight and under what conditions, as long as an acceptable level of safety is maintained. It's derived from the Master Minimum Equipment List, or MMEL, which you also see listed on pages 145 and 146. MET stands for Meteorological Reports, found on page 135. These are the weather reports you'll use for flight planning and briefing. Meteorological Visibility is on page 57. That's the visibility reported by meteorological observers, measured in meters or kilometres, and it's distinct from the flight visibility you see from the cockpit. Microburst is on pages 179 and 180. A microburst is a localized, intense downdraft that can cause severe wind shear, especially dangerous during takeoff and landing. Minimum Aircraft System Performance Specification appears on page 122. That's a standard that defines the minimum performance requirements for certain aircraft systems, often related to navigation or communication. Minimum Crew Rest is on page 107. This refers to the regulatory minimum rest period that must be provided to flight crew between duty periods to ensure they are fit for duty. Minimum Descent Height — we already saw MDH — is spelled out on page 61. That's the same concept: the lowest altitude for a non-precision approach. Minimum Equipment List (MEL) appears again on page 13, 27, 73, and 145. The index gives you the full expansion here. Minimum Flight Altitudes are on page 41. These are the lowest altitudes you can fly in a given airspace or route segment, based on terrain clearance and obstacle clearance requirements. Minimum Navigation Performance Specification Airspace, abbreviated MNPSA, is on page 119. This is airspace where aircraft must meet a specific navigation performance standard to operate. Minimum Navigation Performance Specification, or MNPS, is on page 40. That's the performance standard itself — a requirement for navigation accuracy and integrity. Minimum Time Routes are on page 114. These are routes that minimize flight time, often using favourable winds. Minimum Time Tracks, or MTT, are on page 123. Similar concept, but tracks are the actual paths flown, often over oceanic areas. MLS stands for Microwave Landing System, found on pages 62 and 82. That's a precision approach guidance system that uses microwave frequencies, an alternative to ILS. MMEL is the Master Minimum Equipment List, pages 145 and 146. This is the industry-standard list from which each airline derives its own MEL. MNPS appears again on pages 40, 82, 120, 122, 123, 131, 132, and 134. That's the Minimum Navigation Performance Specification. MNPSA is on pages 40, 119, 136, 137, and 138 — the airspace where MNPS applies. MTT is Minimum Time Tracks, page 123. Now moving into the N entries. NADP 1 and NADP 2 are on pages 150 and 153. These stand for Noise Abatement Departure Procedures. NADP 1 is designed to reduce noise close to the airport, while NADP 2 reduces noise further out. You'll need to know which one to use based on local procedures. NAR is on pages 125 and 131. That stands for North Atlantic Route — the organized track system across the North Atlantic. NAT is on pages 131, 134, and 136 — that's the North Atlantic region itself. NAT MNPSA is on page 120 — the North Atlantic Minimum Navigation Performance Specification Airspace. And finally, NAT Region — the North Atlantic Region — is listed, and the page number continues on the next line of the index. That covers the M and N entries in the index. Each of these terms will be explained in full detail on the pages referenced.