Flashcards

8 cards showing.

MSL vs AGL — definitions and sectional chart rule?

essential airspace

AGL — Above Ground Level (height above terrain).
MSL — Mean Sea Level (absolute elevation).
On sectional charts: all altitudes MSL unless in parentheses — (12) means 1 200 ft AGL.
Add 00 to the printed number.

💡

Parens = AGL. No parens = MSL. Always add 00. So 70/30 = 7000/3000 MSL; (12) = 1200 AGL.

airspace/msl-vs-agl

Class D airspace — altitudes, sectional marking?

essential airspace

D = Dashed blue Donut.

📐 Altitudes
- Floor: surface
- Ceiling: typically 2 500 ft AGL
🎨 Sectional marking: 🟦 dashed blue lines
🏛️ Shape: single cylinder, ~4–5 NM radius
🛸 sUAS rule: ATC authorization required (via LAANC)
🏛️ Found at: small towered airports

💡

D = Dashed blue Donut. Small 4-5 NM cylinder, 2500 AGL.

airspace/class-d

Class A airspace — altitude?

essential airspace

FL 180 – FL 600 MSL (18 000 ft to 60 000 ft MSL). IFR only. Not a drone concern — sUAS capped at 400 ft AGL.

💡

A = Airliners. Above FL180. Never a drone's problem.

airspace/class-a

Class C airspace — altitudes, sectional marking, drone rule?

essential airspace

📐 Altitudes
- Floor: surface (in core)
- Ceiling: typically 4 000 ft AGL
🎨 Sectional marking: 🟪 solid magenta lines
🏛️ Shape: two-ring layer cake
- Inner ring: 5 NM radius, SFC – 4 000 AGL
- Outer shelf: 10 NM radius, 1 200 AGL – 4 000 AGL
🛸 sUAS rule: ATC authorization required
🏛️ Found at: Syracuse, Cleveland, Albany — mid-size towered airports

💡

C = Solid magenta (think 'Cs = solid'). 4000 AGL ceiling. Rings 5/10 NM.

airspace/class-c

Class E airspace — three common variants and their sectional markings?

essential airspace

E = Everywhere-else controlled. Three flavors:

🟪 Surface-designated (dashed magenta line)
- Floor: surface
- Around airports without towers
- sUAS rule: authorization required
🟪 700 AGL floor (shaded magenta)
- Floor: 700 ft AGL
- Drones under 400 AGL stay below E → no authorization needed
🟦 1 200 AGL floor (shaded blue)
- Floor: 1 200 ft AGL
- “Default” controlled airspace away from airports
- No authorization needed for sUAS

⚠️ Only the surface-designated version requires LAANC.

💡

E = Everywhere-else controlled. Dashed magenta = surface E (authorization). Shaded magenta = 700 AGL floor. Shaded blue = 1200 AGL floor.

airspace/class-e-variants

GOES satellites — orbit and primary instrument?

likely airspace

🛰️ Orbit: geostationary
- Altitude ~36 000 km (22 236 mi) above the equator
- Orbital period matches Earth’s rotation → appears stationary over one hemisphere
📷 Primary instrument: ABI (Advanced Baseline Imager)
- 16 bands (2 visible, 4 near-IR, 10 IR)
- Full-disk scan every 10 min, CONUS every 5 min
🌪️ Used for: weather, hurricanes, wildfires, fog, severe storms

⚠️ Don’t confuse with Landsat (705 km, polar). Geostationary = 0° inclination, very high altitude.

💡

GOES parks over the equator at ~36 000 km. Don't confuse with Landsat (705 km, polar). Geostationary = zero inclination, matches Earth's rotation.

airspace/goes-orbit

Class B airspace — altitudes, sectional marking, drone rule?

essential airspace

B = Big, Busy, Blue.

📐 Altitudes
- Floor: surface (SFC)
- Ceiling: typically 10 000 ft MSL
🎨 Sectional marking: 🟦 solid blue lines
🏛️ Shape: inverted wedding cake — tiers expand upward and outward
🛸 sUAS rule: ATC authorization required (via LAANC)
🏙️ Found at: the busiest US airports — JFK, ORD, ATL, LAX, BOS, SFO

💡

B = Big, Busy, Blue. Solid Blue lines. Wedding-cake tiers to 10 000 MSL.

airspace/class-b

CTAF, ATIS, AWOS, ASOS — what are they?

maybe airspace

📻 CTAF — Common Traffic Advisory Frequency
- Pilots self-announce at uncontrolled fields
📻 ATIS — Automatic Terminal Information Service
- Recorded weather + ops broadcast at towered airports
🌡️ AWOS — Automated Weather Observing System
- Continuous automated weather, FAA-operated
🌡️ ASOS — Automated Surface Observing System
- Continuous automated weather, NWS-operated (more sensors)

airspace/airport-advisory