Airports, Air Traffic Control, and Airspace Notes
Runway and Airport Markings & Signs
Runway Numbering
Runways are numbered based on their magnetic direction.
They are aligned and numbered to the nearest 10 degrees of their magnetic azimuth.
The last "0" is dropped from the number (e.g., 360 degrees becomes runway 36).
Opposite Runway Calculation: To find the opposite runway, subtract or add 18 to the runway number (which corresponds to a 180-degree difference). For example, for runway 36, you take the numbers 3 and 6: 3-2=1 and 6+2=8, resulting in runway 18. Another simpler way is to add/subtract 18 from the runway number, or directly add/subtract 180 degrees to the magnetic direction and then drop the last '0'.
Threshold
The beginning of the runway available for all operations: takeoff, landing, and taxiing.
Displaced Threshold
This is a runway threshold that is not located at the beginning of the paved surface of the runway.
It is usually displaced due to an obstruction that requires additional clearance for landing aircraft.
Usage: The area before a displaced threshold can be used for taxiing and takeoff. It can also be used for landing rollout if landing from the opposite runway direction.
Markings: Marked with a solid white line (the runway threshold bar). Arrows are painted on the surface before this solid line, indicating the displaced threshold.
Structural Strength: The area before the displaced threshold is typically not suitable for a full-strength landing impact.
Chevrons
Markings: Yellow markings.
Usage: Indicate an area that is UNUSABLE for takeoff, landing, or taxiing.
Structural Condition: This area is structurally unsound.
Purpose: Often serves as a blast pad (to protect the runway from jet blast erosion) or a stopway for emergency operations from the opposite runway.
Closed Runways
Marked with a large "X".
Runway Holding Position Markings
Consist of solid yellow lines closer to the runway and dashed yellow lines on the side away from the runway.
Rule: Pilots must hold short, or not cross, the solid yellow lines without an Air Traffic Control (ATC) clearance. This is comparable to "driving rules" where a solid line indicates a point you should not cross.
Airport Signs
Location Signs: Black background with yellow letters/numbers. They indicate your current location on the airport. (Example: A sign with an "A" on a black background indicates you are on Taxiway A).
Direction Signs: Yellow background with black letters/numbers. Used on a taxiway or runway to indicate directions of other taxiways leading out of an intersection (e.g., taxiway intersecting a taxiway, or a runway intersecting a taxiway).
Destination Signs: Yellow background with black letters/numbers. Indicate directions to runways, terminals, ramps, Fixed-Base Operators (FBOs), or military areas. Outbound destination signs specifically define directions to takeoff runways.
Runway Holding Position Sign (Mandatory Instruction Sign)
Appearance: Red background with white numbers.
Purpose: These are mandatory instruction signs indicating a point where an aircraft must hold short of a runway or critical area unless cleared by ATC.
Correlation: The numbers on the sign correspond with the runway designations (e.g., 15-33).
Location: Found on taxiways and also on runways, particularly for Land And Hold Short Operations (LAHSO).
Combination: On taxiways, runway holding positions are indicated by both the sign and the holding position markings on the pavement.
Taxiway Ending Sign
Indicates the end of a taxiway.
Runway Distance Remaining Signs
Appearance: Black background with white numbers.
Information: Indicate the runway distance remaining in thousands of feet (e.g., a sign with "18" means 1,800 feet of runway remain).
ILS Critical Area
Purpose: An area designated to protect the integrity of the Instrument Landing System (ILS) localizer and glidepath radio signals.
Interference: Aircraft in this area can interfere with these sensitive radio signals.
Markings and Instruction: When ATC protects the ILS critical area and instructs aircraft to hold short, pilots must stop so no part of the aircraft extends beyond the ILS Critical Area Holding Position Markings.
Demarcation Bar
Appearance: A wide (e.g., 3 feet wide), solid yellow line.
Purpose: Separates a displaced threshold from a blast pad, stopway, or a taxiway that precedes the runway.
Airport Lighting & Visual Aids
Airport Beacon
Location: Typically found at Class "D" airports.
Operation: During the day, it is turned on when Visual Flight Rules (VFR) conditions do not exist, specifically when visibility is less than 3 miles and/or the ceiling is less than 1,000 feet.
Taxiway Lights
Blue edge lights, marking the edges of taxiways.
Runway Lights
White edge lights, marking the edges of runways.
Pilot Controlled Lighting (PCL)
Activation: Pilots can activate runway and taxiway lights at uncontrolled airports (or when a control tower is closed) by keying their aircraft's radio microphone on a specified frequency.
Intensity Levels:
Clicking 7 times activates High Intensity lights.
Clicking 5 times activates Medium Intensity lights.
Clicking 3 times activates Low Intensity lights.
Airport Traffic Pattern
Standard Pattern: Typically involves left turns.
Pattern Altitude: Usually 1,000 feet Above Ground Level (AGL).
Recommended Entry: A 45-degree entry to the midfield downwind leg of the pattern.
Entry Procedure:
Fly clear of the traffic pattern, approximately 2 miles out, at circuit altitude plus 500 feet.
Descend to the pattern altitude.
Yield to downwind traffic and make a 45-degree turn to enter the midfield downwind leg.
Segmented Circle
Location: Found at uncontrolled airfields.
Purpose: Provides visual traffic pattern information, including wind direction and recommended runway for landing.
Associated Indicators: If no segmented circle is present, landing strip indicators are usually located near the end of the runway.
Wind Direction Indicators
Tetrahedron: Land in the same direction that the tip of the tetrahedron is pointing.
Wind "T": Land toward the crossbar of the wind "T".
Wind Cone (Wind Sock): Land as if you were going to fly out of the large (open) end of the wind cone.
Visual Approach Slope Indicator (VASI)
Function: Projects a visual glide path for landing aircraft; it does not provide alignment guidance.
Components: Typically consists of two bars of lights (a far bar and a near bar).
Indications:
"Red over red your dead": Both the far and near bars show red lights, indicating the aircraft is BELOW the glide path.
"Red over white your alright": The far bar shows red lights, and the near bar shows white lights, indicating the aircraft is ON the glide path.
"White over white your out of sight": Both the far and near bars show white lights, indicating the aircraft is ABOVE the glide path.
Precision Approach Path Indicator (PAPI)
Function: Provides precise visual glide path guidance, similar to VASI but usually with four lights arranged horizontally.
Indications (4-Unit Display):
All White: Too High.
Three White, One Red: Slightly High.
Two White, Two Red: On Slope (on glide path).
One White, Three Red: Slightly Low.
All Red: Too Low.
Pulsating/Steady Light Indications (as described in the transcript, potentially simplifying a PAPI or related system):
Pulsating Red: Indicates the aircraft is Low.
Steady Red: Indicates the aircraft is Slightly Low.
Steady White: Indicates the aircraft is On Glide Path.
Pulsating White: Indicates the aircraft is High.
Wake Turbulence & Aircraft Lighting
Wingtip Vortices (Wake Turbulence)
Formation: Only developed when an aircraft is creating lift.
Strength: Greatest strength when the aircraft is heavy, clean (flaps and landing gear retracted), and slow.
Movement: Vortices move outward, upward, and then around each wingtip.
Behavior: They will tend to sink into the flight path of following aircraft.
Avoidance Strategies:
On Takeoff: Rotate prior to the preceding aircraft's rotation point and climb above its flight path.
On Landing: Stay above the preceding aircraft's flight path and land beyond its point of touchdown.
Most Dangerous Condition: Wake turbulence is most dangerous with a light quartering tailwind, which can hold the vortices over the runway.
Aircraft Lighting
Navigation Lights:
Red: On the left wingtip.
Green: On the right wingtip.
White: On the tail.
Visibility Rules: You cannot see the red or green lights from directly behind the aircraft. You cannot see the white tail light from directly in front of the aircraft.
Anticollision Lights:
Strobes: Flashing white lights, typically on the wingtips.
Beacon: Can be seen from all angles. Usually a flashing red rotating light, often located on the top or bottom of the fuselage (often the tail section).
Traffic Avoidance & Communication
Identifying Collision Course: Any aircraft that appears to show little or no relative movement in your field of view is likely on a collision course with your aircraft.
Scanning for Traffic:
During the Day: Use small, regular intervals, scanning no more than 10 degrees at a time, for at least 1 second per interval.
During the Night: Use off-center (peripheral) vision. The fovea (center of vision) has a blind spot in low light conditions, so looking slightly away from a faint light helps it become more visible.
Pilot Responsibility for Traffic Avoidance:
Pilots should regularly scan for traffic before each maneuver.
When climbing and descending, make small turns along the airway to provide maximum visibility of the surrounding airspace.
All pilots are ultimately responsible for seeing and avoiding other aircraft.
Prevalence of Mid-Air Collisions: Most mid-air collisions, surprisingly, occur on clear VFR days, highlighting the importance of diligent visual scanning.
Near Mid Air Collision (NMAC)
Definition: Being less than 500 feet away from another aircraft.
Reporting: A report received from a pilot or co-pilot indicating that a near mid-air collision occurred.
Reference: Further details are available in the Aeronautical Information Manual (AIM) section 7-6-3.
Landing Light Use: Pilots are encouraged to have their landing light on below 10,000 feet MSL to increase visibility to other aircraft.
ADS-B (Automatic Dependent Surveillance-Broadcast)
Function: Allows ATC to see aircraft with greater precision than traditional radar by utilizing GPS signals.
Advantages:
Works effectively in mountainous terrain.
Functions reliably at low altitudes and even on the ground.
Can monitor aircraft on taxiways and runways.
Provides weather information without requiring a subscription.
Requirement: Was required by 2020 for most aircraft operating in controlled airspace where a transponder is generally required.
Radio Communications
VHF Equipment:
Consists of a transceiver, capable of both transmitting and receiving radio signals.
Operates in the frequency range of 118.00-135.975 MHz.
VHF Limitations: Limited to line of sight. Radio waves can be blocked by obstructions such as buildings, terrain, or the curvature of the earth.
Communication Etiquette:
Listen first to ensure the frequency is clear.
Do not interrupt ongoing transmissions.
Keep transmissions brief; think for a minute before keying the microphone.
Speak professionally and avoid slang.
Ensure your microphone is not stuck in the "transmit" position (which would block the frequency for everyone).
Phonetics and Pronunciation:
Use the standard phonetic alphabet (e.g., "Alpha", "Bravo").
Pronounce the number nine as "Niner" to avoid confusion with "five".
For radio frequencies, pronounce the decimal point as "point" (e.g., 121.5 is "one two one point five").
For altimeter settings, omit the "point" (e.g., 29.92 is "two niner niner two").
Initial Contact: Use the full aircraft registration number or aircraft make. Drop the "N" prefix (e.g., "Cessna One Two Three Alpha Bravo") only after ATC shortens it.
Number Pronunciation: For thousands, state the full number (e.g., 8500 is "eight thousand five hundred").
Lost Communication Procedures
In case of radio failure, pilots should be prepared to follow light gun signals from the control tower.
Light Gun Signals (from Control Tower)
For Aircraft on the Ground:
Steady Green: Cleared for takeoff.
Flashing Green: Cleared for taxi.
Steady Red: Stop.
Flashing Red: Clear the taxiway/runway in use.
Flashing White: Return to starting point on airport.
Alternating Red and Green: Exercise extreme caution.
For Aircraft in Flight:
Steady Green: Cleared to land.
Flashing Green: Return for landing (to be followed by a steady green at the proper time).
Steady Red: Give way to other aircraft and continue circling.
Flashing Red: Airport unsafe, do not land.
Flashing White: Not applicable.
Alternating Red and Green: Exercise extreme caution.
Airport Terminal Facilities & ATC Services
Airport Terminal Facilities (typical sequence):
ATIS (Automatic Terminal Information Service)
Clearance Delivery
Ground Control
Control Tower
Departure Control
Approach Control
ATIS (Automatic Terminal Information Service)
A continuous broadcast of important, non-control information at busy airports.
Includes: weather (wind, visibility, sky condition, temperature, dew point, altimeter setting), active runways, and other pertinent airport information.
Information Omissions: Ceilings are omitted when above 5,000 feet. Visibility is usually not mentioned when above 5 statute miles.
Ground Control
Taxi Clearance: Pilots must obtain clearance to taxi before moving the aircraft. This clearance is typically only to taxi to the active runway, not onto it.
Crossing Runways: Pilots are not cleared to cross other runways without specific instruction from Ground Control.
"Line Up and Wait": This clearance allows an aircraft to taxi onto the runway and position itself for takeoff, but it is not a clearance for takeoff. The aircraft must await a separate takeoff clearance.
Post-Landing: After landing, switch to Ground Control only if specifically instructed to do so by the Control Tower.
FSS (Flight Service Station)
Provides a variety of services to pilots, including:
Weather briefings.
Filing flight plans.
Providing search and rescue services.
VHF/DF (VHF Radio Direction Finder): FSS facilities equipped with VHF/DF can help pilots determine their position or provide headings to an airport if the pilot keys their microphone for a brief duration.
ARTCC (Air Route Traffic Control Centers)
Coverage: Have extensive radar coverage, managing air traffic over large geographical areas.
Authority: Primarily responsible for issuing IFR (Instrument Flight Rules) clearances and managing IFR traffic.
VFR Services: Workload permitting, ARTCCs can offer VFR (Visual Flight Rules) aircraft additional services such as traffic advisories, course guidance, and vectors.
Uncontrolled Airports
CTAF (Common Traffic Advisory Frequency): Used at airports without a control tower, or when the tower is closed, for pilots to self-announce their positions and intentions to other pilots.
UNICOM: A privately owned aeronautical advisory station, typically manned. Pilots can use UNICOM to ask for local information, including traffic advisories and fuel services.
MULTICOM: A common frequency (122.9 MHz) designated for use by pilots for air-to-air communication and at airports where there is no FSS or UNICOM to provide advisory services.
Emergency Communications & Procedures
Urgency (Pan-Pan three times)
Indication: A condition of being concerned about safety but not requiring immediate assistance. There is not an imminent danger requiring immediate aid.
Examples:
Doubtful of position (lost).
Unsure of fuel remaining.
Encountering deteriorating weather conditions.
Distress (Mayday three times)
Indication: A condition of imminent danger that requires immediate assistance.
Examples:
Aircraft fire.
Serious mechanical failure.
Structural failure of the aircraft.
Transponder Codes for Emergencies
7700: General emergency.
7600: Lost radio communications ("NORDO").
7500: Aircraft hijacking.
Lost Communication Procedures (The "Five C's")
Climb: Climb to a safe altitude known to be free of obstacles, or to the appropriate VFR altitude if in Instrument Meteorological Conditions (IMC).
Communicate: Attempt to communicate on other frequencies, including 121.5 MHz (emergency frequency), or by squawking 7600 on the transponder.
Confess: Once contact is made, confess the nature of the emergency (e.g., "We are lost," "We have an engine issue").
Comply: Comply with any instructions given by ATC or emergency services.
Conserve: Conserve fuel and other resources as appropriate to the situation.
VHF/DF: Airports equipped with Direction Finder systems can assist lost aircraft by providing an approach to the airport.
ELT (Emergency Locator Transmitter)
Activation: Activates automatically upon impact from crash-generated forces (e.g., a hard landing) or can be manually turned on by the pilot.
Transmission: Transmits a distinctive tone on the emergency frequency of 121.5 MHz.
Monitoring: Pilots should monitor 121.5 MHz during flight for potential distress signals.
Battery Life: The transmitter should operate continuously for 48 hours or longer to aid in Search and Rescue (SAR) operations.
Testing: ELT testing must be conducted on the ground, within the first 5 minutes after the hour, and for a maximum duration of 3 sweeps (brief bursts of transmission).
Airspace Classes
Airspace is generally divided into uncontrolled airspace (Class G), controlled airspace (Classes A, B, C, D, E), and special use airspace.
Class A Airspace (Above)
Location: Extends from 18,000 feet Mean Sea Level (MSL) up to Flight Level 600 (60,000 feet MSL) over the contiguous United States and Alaska. It also extends 12 nautical miles offshore from the coast.
Requirements:
Pilot Certificate: An Instrument Rating is required for the pilot.
Flight Plan: An IFR flight plan must be filed.
Clearance: An ATC clearance is required to enter (implied for IFR flights).
Communication: Two-way radio communication is required.
Transponder: An altitude-encoding (Mode C) transponder is required.
Altimeter Setting: All aircraft operating in Class A airspace must set their altimeters to 29.92 inches of mercury.
Charting: Class A airspace is not depicted on VFR nautical charts.
Example: Flight Level 370 (FL370) corresponds to 37,000 feet MSL.
VFR Minimums: VFR flight is not permitted in Class A airspace.
Class B Airspace (Busy Airports)
Location: Generally surrounds the nation's busiest airports (e.g., New York, Philadelphia). It is individually tailored for each airport and typically resembles an "upside-down wedding cake" shape.
Requirements:
Pilot Certificate: A private pilot certificate is required, or a student pilot with a specific logbook endorsement from an instructor.
Clearance: Explicit ATC clearance, stating "Cleared into Class B airspace," is mandatory for entry. Simply making radio contact or receiving acknowledgment of your call sign is not a clearance to enter.
Communication: Two-way radio communication is required.
Transponder: An altitude-encoding (Mode C) transponder is required when operating within Class B airspace or within 30 nautical miles of the primary Class B airport, at or above 10,000 feet MSL.
VFR Minimums:
Visibility: 3 statute miles.
Cloud Clearance: Clear of clouds.
Class C Airspace (Medium Size Airports)
Location: Surrounds most medium-sized airports that have an operating control tower and radar approach control.
Dimensions:
Typically consists of a 5-nautical-mile radius inner core surface area extending from the surface up to 4,000 feet AGL.
An outer shelf area with a 10-nautical-mile radius, extending from 1,200 feet AGL up to 4,000 feet AGL.
Requirements:
Communication: Establish and maintain two-way radio communication before entering.
Transponder: A Mode C (altitude-encoding) transponder is required.
VFR Minimums:
Visibility: 3 statute miles.
Cloud Clearance: 500 feet below, 1,000 feet above, and 2,000 feet horizontal from clouds (often remembered as "3-152").
Class D Airspace (Smaller Airports)
Location: Surrounds smaller airports that have an operating control tower.
Dimensions: Generally a 4-nautical-mile radius extending from the surface up to 2,500 feet AGL.
Dynamic Nature: Reverts to Class E airspace when the control tower is closed.
Requirements:
Communication: Establish and maintain two-way radio communication.
Speed: Aircraft speed must be less than 200 knots within this airspace.
VFR Minimums:
Visibility: 3 statute miles.
Cloud Clearance: 500 feet below, 1,000 feet above, and 2,000 feet horizontal from clouds ("3-152").
Class E Airspace (Controlled Airspace - General Use)
Location: Controlled airspace not designated as Class A, B, C, or D. Generally extends from 1,200 feet AGL up to 18,000 feet MSL, or from 700 feet AGL in transition areas around airports. Can also extend to the surface in designated areas (e.g., for instrument approaches).
Requirements:
Pilot Certificate: None specified for VFR flight.
IFR: IFR flights require ATC clearance.
Transponder: Not required unless operating above 10,000 feet MSL (where a Mode C transponder is required).
VFR Minimums:
Below 10,000 feet MSL: 3 statute miles visibility, 500 feet below, 1,000 feet above, and 2,000 feet horizontal from clouds ("3-152").
At or Above 10,000 feet MSL: 5 statute miles visibility, 1,000 feet below, 1,000 feet above, and 1 statute mile horizontal from clouds.
Class G Airspace (Uncontrolled Airspace)
Location: Airspace where ATC has no authority or responsibility to control air traffic. Generally extends from the surface up to 1,200 feet AGL, though in some remote areas it may extend up to 14,500 feet MSL where not designated as Class E.
Requirements: No specific entry requirements for VFR flight.
VFR Minimums:
Below 1,200 feet AGL:
Day: 1 statute mile visibility, clear of clouds.
Night: 3 statute miles visibility, 500 feet below, 1,000 feet above, 2,000 feet horizontal from clouds.
Above 1,200 feet AGL but below 10,000 feet MSL:
Day: 1 statute mile visibility, 500 feet below, 1,000 feet above, 2,000 feet horizontal from clouds.
Night: 3 statute miles visibility, 500 feet below, 1,000 feet above, 2,000 feet horizontal from clouds.
At or Above 10,000 feet MSL: 5 statute miles visibility, 1,000 feet below, 1,000 feet above, 1 statute mile horizontal from clouds.
TRSA (Terminal Radar Service Area)
Nature: TRSA is not a class of airspace but a designated area where ATC provides additional radar services for VFR aircraft. Participation is voluntary but highly recommended.
Services: Provides basic radar services for participating aircraft, including traffic advisories, safety alerts, and vectors to aid in navigation near busy terminal areas.
Communication:
When inbound, contact approach control.
When outbound, contact ground control on initial call with your direction of flight.