FL70 = The Minimum En Route IFR Altitude (MEA): The lowest published altitude — Page 180, Lesson 187

I want to walk you through a set of annotated chart symbols and procedural notes that appear on Jeppesen approach and area charts. These are the kind of details you'll see printed directly on the chart itself, and each one carries a specific operational meaning. Let's start with the first entry. FL70 is the label for the Minimum En Route IFR Altitude, abbreviated MEA. This is defined as the lowest published altitude between radio fixes. It serves two purposes: first, it meets obstacle clearance requirements between those fixes, and second, in many countries it assures acceptable navigational signal coverage. The MEA applies to the full width of the airway, segment, or route between the radio fixes that define that airway segment or route. So when you see an MEA on a chart, you know that as long as you stay at or above that altitude within the lateral limits of that airway, you are protected from obstacles and, in most cases, you'll have reliable reception of the navigation aids defining that route. Next we have 2100a, which is the Minimum Off-route Altitude. This is an altitude value derived by Jeppesen, and it provides known obstruction clearance within 10 nautical miles of the route centre line. So if you are operating off the published airway structure, this altitude gives you a floor for terrain and obstacle protection within that 10 NM corridor. Now look at the symbol ψ — that's the Greek letter psi. On this chart it indicates A20, which is normally a one-way westbound route for airfields and flight levels as listed, at a position defined by coordinates N50 35 W00615. The blue thickly dashed line on the chart represents AREA CHART coverage for London, UK, specifically for EGLL, which is London Heathrow. That dashed boundary tells you the geographical extent of the area chart. Moving on, the semi-circle symbol is a bypass symbol. It means that the waypoint or restriction labelled CLIFF does not apply to route G27; it only applies to A20 and the ATS route to SFD VOR. So if you are flying G27, you ignore the CLIFF restriction. You'll also see 2400' noted. That value refers you to page 6 of the Jeppesen Chart Glossary for its full meaning — it's a standard reference annotation. Next, SLP stands for Speed Limiting Point. Its symbol on the chart is a shaded square. The X symbol represents a non-compulsory airspace fix — you are not required to cross it, but it is a defined point for navigation or procedural reference. The chart then instructs: Maintain maximum IAS of 250 kt from a position 3 minutes before the holding facility, or the SLP position shown on the chart. So you have two possible trigger points for that speed restriction: either three minutes prior to reaching the holding facility, or at the SLP symbol if one is depicted. Then we have FL150 by TIGER. This is a crossing restriction — you must be at flight level 150 by the fix named TIGER. But the note adds: ACTUAL DESCENT CLEARANCE WILL BE AS DIRECTED BY ATC. So the charted altitude is a planning constraint; you still need a specific descent clearance from air traffic control. For holding speeds: Holding speed in the LONDON TMA up to and including FL140 is maximum IAS 220 kt. At FL 150 and above standard ICAO holding speeds apply. So within the London Terminal Manoeuvring Area, if you are holding at or below FL140, your maximum indicated airspeed is 220 knots. Once you reach FL150 or higher, you revert to the standard ICAO holding speed categories, which vary by altitude band. You'll also see three VOR radials listed: SFD VOR 076, LYD VOR 222, BIG VOR 139. These are likely radials to be used for navigation or intercept procedures in that area. There is a noise monitoring point symbol on the chart — that marks a location where noise levels are measured for compliance with local noise abatement procedures. A standard speed restriction: MAX IAS 250 kt below FL100 unless otherwise instructed by ATC. This is a common speed limit in controlled airspace below 10,000 feet. Then ABB 8A — that is a chart reference or identifier for a specific procedure or note. Next, a climb gradient requirement: Minimum climb gradient 5.5% up to FL150. Intercept the VOR CGN 268 radial; at 1.5 NM from CGN DME turn right. So if you are on a departure or missed approach, you must achieve at least a 5.5 percent climb gradient until you reach FL150. You then intercept the 268 radial from the CGN VOR, and once you are 1.5 nautical miles from the CGN DME, you execute a right turn. A specific rate is given: 1281 ft/min. That is the required rate of climb in feet per minute corresponding to that 5.5 percent gradient at a particular groundspeed — the chart provides that value for your reference. Then there is a reference: See LONDON, UK NOISE HEATHROW. And two noise limits: 97 dBA 0700 - 2300 LT; 89 dBA 2300 - 0700 LT. These are maximum noise levels in decibels, A-weighted, measured at the noise monitoring point. The first applies during daytime and evening hours, the second during night hours. Next: 160 kt = CAT D aircraft (see page 1 Glossary). This tells you that an approach speed of 160 knots indicated corresponds to Category D aircraft under the ICAO approach speed classification. Category D is for aircraft with a speed range between 141 and 165 knots. Finally, we have approach minima: DH 100' DA 177'. That is a decision height of 100 feet and a decision altitude of 177 feet. Radio Altitude (RA) 100' — the decision height is referenced to radio altitude. RVR 350 m — the required runway visual range is 350 metres for the approach. Then a note: Touchdown Zone (TDZ) or Centre line Lights (CL) out, the RVR = 550 m, with Autoland = 300 m. So if the touchdown zone lights or centre line lights are inoperative, the minimum RVR increases to 550 metres. However, if the aircraft is equipped and certified for autoland, the RVR can be as low as 300 metres even with those lights out. These are the key chart annotations from this excerpt. Each one is a piece of operational data you must interpret correctly when briefing and flying an instrument procedure.