• What is the MSA to the East of the airfield? — Page 158, Lesson 164

I want to walk you through a set of questions that are typical of the kind of chart-reading and procedure-interpretation tasks you'll face in flight planning and monitoring. These questions are based on an instrument approach chart and a Standard Instrument Departure (SID) chart, and they test your ability to decode the symbols, numbers, and procedures that are standardised across aviation. Let's start with the first block of questions, which relate to an approach chart. The first question asks: What is the MSA to the East of the airfield? MSA stands for Minimum Sector Altitude. That is the lowest altitude you can fly within a given sector (usually a 25 NM radius from a navigation aid) and still have at least 1,000 feet of obstacle clearance in non-mountainous terrain, or 2,000 feet in designated mountainous areas. The question is asking you to read that value off the chart for the eastern sector. Next, question c says "Decode" with a symbol that looks like a small black square or diamond — that's likely a symbol for a navigation aid or a fix. You'd need to identify what that symbol represents on the chart. Question d says: Decode LOC * 109.5 ILL. LOC stands for Localizer, which is the lateral guidance component of an Instrument Landing System (ILS). The frequency is 109.5 MHz, and ILL is the identifier for that specific localizer station — likely the one serving runway 27L at this airfield. The asterisk might indicate a specific note or condition on the chart. Question e asks you to decode the information at BOVINGDON. Bovingdon is likely a waypoint, a VOR, or a reporting point on the chart. You'd need to read its coordinates, frequency, and any altitude or route constraints. Question f says: Describe the MISSED APPROACH HOLDING south of BNN VOR/DME. BNN is a VOR/DME station — VHF Omnidirectional Range with Distance Measuring Equipment. The missed approach holding is a racetrack pattern you fly if you go around after a missed approach. This one is located south of BNN, and you'd need to describe its inbound track, direction of turns, and altitude. Question g asks you to state the difference between the route delineated by the 137 radial from the BNN VOR and its arrowhead at 19 NM from the BNN DME and the route and arrowhead delineated by the 096 radial from LON VOR/DME. A radial is a magnetic bearing from a VOR. So the 137 radial from BNN is a line extending outward at 137° magnetic. The arrowhead at 19 NM indicates a specific point along that radial. Similarly, the 096 radial from LON VOR/DME gives another line. The question wants you to compare how these two routes and their arrowheads differ — likely in direction, distance, or purpose. Question h asks: What is the inbound track of the ILS localiser beam? The localiser beam is aligned with the runway centreline. The inbound track is the magnetic heading you fly toward the runway when established on the localiser. For runway 27L, that would be approximately 270° magnetic, but you'd read the exact value from the chart. Question i asks: Where can the details of the danger area EG (D) - 133 be found? Decode the details. EG (D) - 133 is a designated danger area in UK airspace. The details — its vertical limits, times of activation, and controlling authority — are typically found in the UK AIP (Aeronautical Information Publication) or on the chart itself in a legend or notes block. Now we move to the Profile View and Landing Minimums section. Question j: What is the elevation of the threshold of runway 27L? The threshold elevation is the height of the runway's beginning above mean sea level, given in feet. You read it directly from the chart. Question k: What are the recommended height and altitude at 4 NM from the ILL ILS DME when the ILS glide slope is unserviceable? If the glide slope is out, you cannot fly a precision approach. Instead, you'd fly a localiser-only approach, and the chart provides a recommended crossing altitude at 4 NM from the DME to help you descend safely to the Minimum Descent Altitude. Question l: Decode: OCA (H) RWY 27L. ILS D: 264’ (187’). OCA stands for Obstacle Clearance Altitude, and the (H) means it's the height above the threshold. For runway 27L, the ILS D (Category D aircraft) OCA is 264 feet above mean sea level, and the height above the threshold is 187 feet. This is the lowest altitude you can descend to on the ILS without visual reference, ensuring obstacle clearance. Question m: Decode TCH 56’. TCH stands for Threshold Crossing Height — the height of the ILS glide slope's centreline at the runway threshold. Here it's 56 feet above the threshold elevation. Question n: Explain the meaning of the propeller symbol. On approach charts, a propeller symbol typically indicates a non-precision approach that uses a different type of guidance, or it may mark a specific type of missed approach or circling procedure. You'd confirm its exact meaning from the chart's legend. Question o: Decode GS 1405’ (1328’). GS stands for Glide Slope. The number 1405 feet is the altitude of the glide slope at a specific point (usually at the outer marker or a DME fix), and the 1328 feet in parentheses is the height above the threshold at that same point. Question p: What does - - - - - M - and signify? The dashed line with an 'M' likely marks the Missed Approach Point on the profile view, and the arrow or symbol indicates the direction of the missed approach procedure. Question q: Quote the DA/H for the ILS precision approach and the MDA/H for the localizer only (glide slope out) non-precision approach. DA/H stands for Decision Altitude/Height — the altitude on a precision approach at which you must have visual reference to continue, or you execute a missed approach. MDA/H stands for Minimum Descent Altitude/Height — the lowest altitude you can descend to on a non-precision approach without visual reference. You'd read both values from the chart's minima table. Question r: What is the missed approach procedure? This is the published sequence of actions — including heading, altitude, and any holding pattern — that you fly if you go around after a missed approach. You'd describe it exactly as written on the chart. Now, question s asks you to define several key terms: - Non-precision approach and landing operations: An instrument approach that provides lateral guidance only (e.g., localiser, VOR, NDB) but no vertical guidance. You must use a published MDA/H. - MDA/H: Minimum Descent Altitude/Height — the lowest altitude permitted on a non-precision approach without visual reference. - Precision approach and landing operations: An instrument approach that provides both lateral and vertical guidance (e.g., ILS). You use a DA/H. - DA/H: Decision Altitude/Height — the altitude on a precision approach at which you decide to continue visually or execute a missed approach. - Missed Approach Point: The point on the approach at which the missed approach procedure must be initiated if visual reference is not established. - Missed approach procedure: The published path and altitudes to fly after a missed approach. - RVR: Runway Visual Range — the distance a pilot can see along the runway, measured by instruments, reported in metres. Question t: Decode: ALS out; TDZ or CL out. ALS stands for Approach Lighting System. "ALS out" means the approach lights are unserviceable. TDZ is Touchdown Zone lighting, and CL is Centreline lighting. If either is out, the landing minima (visibility or RVR) may increase. Question u: An aircraft has a ground speed of 150 kt during the descent on the ILS glide path. What is the glide path angle and the required rate of descent? The standard ILS glide path angle is 3°. To calculate rate of descent in feet per minute, you use the formula: ground speed in knots multiplied by 5, then multiplied by the glide path angle in degrees. So 150 × 5 = 750, then 750 × 3 = 2,250 feet per minute. That's your required rate of descent. Question v: Describe the Missed Approach Point (MAP). For a precision approach, the MAP is the point where the glide slope and localiser intersect the DA/H. For a non-precision approach, it's usually a DME fix or a timing point. You'd describe it as published on the chart. Question w: What is the visibility and authorized UK RVR for a C Category aircraft when the touchdown lights are out of service? Aircraft approach categories are based on speed. Category C covers aircraft with approach speeds between 121 and 140 knots. When touchdown zone lights are out, the UK minima typically increase — you'd read the specific values from the chart or the UK AIP. Question x: Define visibility. Visibility is the greatest distance at which a black object of suitable dimensions can be seen and identified against the horizon sky during daylight, or could be seen and identified during night if illumination were raised to normal daylight level. It's reported in metres or kilometres. Now, the next block moves to Example 3 (SID) — a Standard Instrument Departure chart for London Heathrow. Question a: State the transition codes for runways 27R, 27L and 23. Transition codes are alphanumeric designators that tell Air Traffic Control which SID and transition you're cleared to fly. You'd read them from the chart. Question b: What is the procedure after the 2 DME arc on the BROOKMANS PARK SIX HOTEL DEPARTURE? The BPK 6H is a SID. After flying a 2 DME arc (a curved path at a constant 2 NM from a DME station), you'd follow the published routing — likely a radial or heading to the next fix. Question c: With reference to the BPK 6H what does the symbol at N5130.1 W00037.4 signify and what are the direct and curved path ground distances to it? That coordinate is a specific waypoint. The symbol might be a fly-over or fly-by waypoint. The direct distance is the straight-line distance from the departure point, and the curved path distance accounts for the arc you fly. Question d: State the frequency of BUR NDB. BUR is a Non-Directional Beacon. Its frequency is in the 200–1750 kHz range, and you'd read it from the chart. Question e: Quote the altitudes required: i. Crossing the 302 radial. ii. Crossing the 320 radial. iii. At the BPK VOR. These are mandatory crossing altitudes at specific points along the departure — you must be at or above those altitudes when crossing those radials or at the VOR. Question f: An aircraft, cleared for the BPK 6F procedure, is airborne at 0613 UTC. What is its ETA at BPK if its average ground speed is planned to be 240 kt? (use mental arithmetic). You'd need the distance from the departure point to BPK VOR from the chart. If that distance is, say, 20 NM, then time = distance ÷ speed × 60 = 20 ÷ 240 × 60 = 5 minutes. ETA would be 0618 UTC. Question g: State the SPEED CONTROL PROCEDURE. This is a published restriction on the SID — typically a maximum speed below a certain altitude to manage noise or traffic flow. Question h: