Airports without a control tower are classifies as
"uncontrolled". As such, operations at airports without
operating control towers require the highest degree of
vigilance on the part of pilots to see and avoid aircraft
while operating to or from such airports. Pilots should stay
alert at all times, anticipate the unexpected, use the
published CTAF frequency, and follow recommended airport
advisory practices. There are many airport lighting and visual
aids that are available at St. Mary’s County Airport. These
systems are intended to aid the pilot in locating the airport
Precision Approach Path Indicators (PAPIs)
A PAPI is a
system of lights that provide visual descent guidance information during
the approach to a runway. This system provides a visual glide path that
allows for safe obstruction clearance from the start of descent to the
threshold. Both Runway 11 and Runway 29 are equipped with 2-box PAPIs
installed to the left of the threshold.
Runway End Identifier Lights
REILs are installed at many airfields to provide rapid and positive
identification of the approach end of a particular runway. They are
effective for: a. Identification of a runway surrounded by a
preponderance of other lighting; b. Identification of a runway
which lacks contrast with surrounding terrain; and c. Identification of a runway during reduced visibility. These lights
consist of a pair of synchronized flashing lights located on each side
of the runway threshold facing the approach area. Both Runway 11 and
Runway 29 have omni-directional REILs. In June 2005 the REIL system
was replaced with funding assistance from the Maryland Aviation
Administration to allow for improved pilot control. Pilots may now
adjust the intensity of the lights as they approach for landing by
keying or “clicking” the aircraft’s microphone in accordance with the
Pilot Control Lighting Operating Procedures outlined below.
Runway Edge Lights
edge lights are used to outline the edges of runways during periods of
darkness or restricted visibility conditions. These light systems are
classified according to the intensity or brightness they are capable of
producing: they are the High Intensity Runway Lights (HIRL), Medium
Intensity Runway Lights (MIRL), and the Low Intensity Runway Lights (LIRL).Runway
11-29 at St. Mary’s County Airport is equipped with MIRLs. In addition,
the Airport is equipped with runway threshold lights at each runway end.
Taxiway Edge Lights
edge lights are used to outline the edges of taxiways. Similar to runway
edge lights, these light systems are classified according to the intensity
of light they are capable of producing. Limited quantities of MITLs have
been installed at St. Mary’s County Airport to delineate the taxiway
turnoffs as well as the midfield connector.
Obstruction Marking and Lighting
In administering Title 14 of the Code of Federal Regulations CFR
Part 77, the prime objectives of the FAA are to promote air safety
and the efficient use of the navigable airspace. To accomplish this
mission, aeronautical studies are conducted based on information
provided by proponents on an FAA Form 7460-1, Notice of Proposed
Construction or Alteration.
Advisory Circular 70/7460-1K, Obstruction Marking and Lighting,
describes the standards for marking and lighting structures such as
buildings, chimneys, antenna towers, cooling towers, storage tanks,
supporting structures of overhead wires, etc. A new Part 77 final
Rule was published on July 21, 2010, and will become effective on
January 18, 2011.
Who Needs to File an FAA Form 7460-1
CFR Title 14 Part 77.13 states that any person/organization who
intends to sponsor any of the following construction or alterations
must notify the Administrator of the FAA:
within 20,000 ft of a public use or military
airport which exceeds a 100:1 surface from any point on the runway
of each airport with at least one runway more than 3,200 ft
within 10,000 ft of a public use or military
airport which exceeds a 50:1 surface from any point on the runway of
each airport with its longest runway no more than 3,200 ft
within 5,000 ft of a public use heliport which
exceeds a 25:1 surface
any highway, railroad or other traverse way whose prescribed
adjusted height would exceed the above noted standards
when requested by the FAA
any construction or alteration located on a
public use airport or heliport regardless of height or location.
and Taxiway Edge Markers
In 2010, the
County received special grant funding from the Maryland Aviation
Administration to purchase retroreflective markers to delineate the
edges of the runway and taxiway. The markers are a safety
enhancement intended to benefit the users of the St. Mary’s County
Regional Airport. The markers are 2.25-inch diameter colored
flexible polyethylene tubes with bands of colored retroreflective
material which were FAA Tested & Certified per FAA AC 150/5345-39.
The colored bands provide daytime marking, improve ground
navigation and also function as snow markers for aircraft and plows
during the winter months.
Control of Airport Lighting Systems
The St. Mary’s County Airport does not have an operating control
tower. Therefore, radio control of lighting is provided via
airborne control of lights by keying the aircraft’s microphone. This
eliminates the need for pilots to change frequencies to turn the lights on
and allows a continuous listening watch on a single frequency. At St.
Mary’s County Airport, the MIRLs and REILs can be activated using the
designated Common Traffic Advisory Frequency (CTAF), 123.0. At this
airport, the CTAF is a UNICOM frequency. In addition, the MIRLs and REILs
are controlled by a photo cell and are automatically turned on at dusk and
during adverse weather.
Pilot Control Lighting
The runway lights are controlled by a photo eye and
via the CATF by “clicking” the microphone.
From dusk until dawn, the runway lights are
turned on to the Low setting by the photo eye.
The runway lights can be changed to the High
setting by clicking the mic 5 times.
They can be set back to Low by clicking the mic 3
During times of heavy overcast, the photo eye may
allow the runway lights to come on during “daylight hours”.
Runway End Identifier Lights (REIL) Strobes:
The REILs are controlled via the CATF by “clicking” the microphone, a
set timer and by a photo eye.
Radio Control System
times within 5 seconds
Highest intensity available
times within 5 seconds
Medium or lower intensity (Lower REIL or REIL-off)
times within 5 seconds
Lowest intensity available (Lower REIL or REIL-off)
NOTE: At any time in the sequence the pilot has the option of sending
three, five, or seven pulses to command the intensity level to his/her
requirements. The system will remain at the intensity level of the last
command received. The solid state timer will continue to operate for 15
minutes after which it will cause the system to revert to the original
“off” condition. The timer is reset by the receipt of any command
at anytime, reinitiating the 15 minute “run” cycle.
photo eye keeps the REILs from operating during the day, but may allow
them to operate during periods of heavy overcast.
Airport (Rotating) Beacon
airport beacon is used to aid pilots in locating the airport using a
rotating green and white light. The ten (10) inch airport beacon at the
Airport is located on top of the County Hangar. A photo eye controls the
rotating beacon. It operates from dusk until dawn and may come on during
periods of heavy overcast.
Wind Cone and Segmented Circle
lighted wind cone and segmented circle is used to aid pilots in
determining takeoff and landing information at an airport. St. Mary’s
County Airport’s lighted wind cone and segmented circle is located to the
north of Runway 11-29 and is in good working condition.
INSTRUMENT APPROACH PROCEDURES
An Instrument Approach Procedure (IAP) is a flight
procedure that provides a transition from the en-route flight environment
to a point from which a safe, normal landing can be accomplished. U.S.
Civil Standard Instrument Approach Procedures are designed and approved
for public use by the Federal Aviation Administration (FAA) and are unique
to each airport.
While these procedures can be flown during good weather
conditions, the instrument approach procedures are especially important
during Instrument Meteorological Conditions (IMC). When the cloud ceilings
are low and visibility is minimal, all flights must follow Instrument
Flight Rules (IFR), and therefore must utilize published instrument
approach procedures when transitioning to the landing environment. The FAA
has established ceiling and visibility minimums for each individual
instrument approach procedure. Currently, there are two (2) published
instrument approach procedures for St. Mary’s County Airport. These
procedures are listed below with the corresponding landing minimums:
VOR OR GPS RWY 29
GPS RWY 11
Standard instrument approach procedures are primarily
based upon either an on-airport or nearby electronic navigational aid (NAVAID)
or the Global Positioning System (GPS). Therefore, the type of instrument
approach procedure is determined by what the procedure is based upon.
One of the instrument approach procedures at St. Mary’s
County Airport is a VOR type procedure. This procedure is based on the
Patuxent VORTAC (PXT, frequency 117.6) located at the Patuxent River Naval
A VORTAC is a navigation aid providing VOR azimuth, TACAN
azimuth, and TACAN distance measuring equipment (DME) at one site. VOR,
TACAN and DME are briefly defined and described below:
VHF Omni-Directional Range (VOR) - A ground-based
electronic navigation aid transmitting very high frequency navigation
signals, 360 degrees in azimuth, oriented from magnetic north. VORs
operate within the 108.0 to 117.95 MHZ frequency band and have a power
output necessary to provide coverage within their assigned service
volume. There are subject to line-of-sight restrictions, and the range
varies proportionally to the altitude of the receiving equipment.
Tactical Air Navigation (TACAN) - A navigational
system developed for use by the military and naval forces.
Distance Measuring Equipment (DME) - Equipment
(airborne and ground) used to measure, in nautical miles, the slant
range distance of an aircraft from the DME navigational aid. Operating
on the line-of-sight principle, DME furnishes distance information
with a high degree of accuracy. DME is typically collocated with other
In addition, two of the instrument approach
procedures can be flown using the Global Positioning System (GPS). GPS is
a system of 24 satellites, orbiting the earth, which emit signals to
receivers below. By measuring the travel time of a signal transmitted from
each satellite, a receiver in the aircraft can calculate its distance from
that satellite. When receiving the signals from at least four (4)
satellites, a receiver can determine latitude, longitude, altitude and
time. The basic GPS service provides users with approximately 100 meter
(328 feet) accuracy 95% of the time anywhere on or near the surface of the
When the civil aviation community first began using the
Global Positioning System (GPS), many existing instrument approaches were
modified to allow pilots with GPS capabilities to fly a published approach
using their approved GPS capabilities instead of the more traditional
NAVAIDS. This type of approach is referred to as a GPS Overlay approach
and is published as an "OR GPS" approach. This type of procedure did not
require any modifications to the existing "base" published procedure.
St. Mary’s County has one GPS Overlay approach procedure,
VOR OR GPS RWY 29.Please note the following FDC
NOTAM that makes the VOR 29 Approach NOT AVAILABLE. The GPS 29 is still
FDC 7/6353 2W6 FI/T ST. MARY'S COUNTY REGIONAL, LEONARDTOWN,
VOR OR GPS RWY 29, AMDT 6A...
VOR PORTION NA.
In addition to the GPS Overlay approaches, in recent years
GPS Stand Alone approaches have been developed as well. This type of
approach is not related to any traditional NAVAID.
St. Mary’s County has one GPS Stand Alone approach
procedure, GPS RWY 11.
NOTAMS (Notice To Airmen)
In the event that conditions at the Airport are determined
to be unsafe for landings or takeoffs, the airport owner is responsible
for providing warning to users, such as adequate marking and issuing a
Notice To Airmen to advise pilots of the condition. Where climatic
conditions render the airport unsafe, the owner will promptly notify
airman by proper notices and, if necessary, close the Airport, or any
portion thereof, for a reasonable period of time or until those unsafe
conditions can be corrected or no longer exist. Additional information can
be obtained from the following
Aircraft Owners and Pilots Association web-site
Current NOTAM's are required by the Federal Aviation
Administration and are available from Flight Services Stations at
1-800-WX-BRIEF. Notices restrictions, and advisories may be
changed at any time and without notice. Do not attempt any
operation in the National Airspace System without first obtaining
and understanding a thorough pre-flight briefing. Pilots may also
wish to view current NOTAM's for St. Mary's Regional Airport
and by typing in "2W6" in the Flight Safety Notams box.
The airport is served by a UNICOM radio. All pilots of
aircraft having radio equipment permitting two-way communications should
contact the Airport UNICOM to obtain advisory information and announce
their intentions when within ten (10) miles of the Airport. Pilots are
also encouraged to maintain a listening watch on the frequency when
operating within a ten mile radius of the Airport. All departing aircraft
shall announce on the UNICOM their intention and runway to be used for
departure. In communicating with a UNICOM station, the following practices
will help reduce frequency congestion, facilitate a better understanding
of pilot intentions, help identify the location of aircraft in the traffic
pattern, and enhance safety of flight:
- Select the correct CTAF frequency.
- State the identification of the UNICOM station you are calling in
- Speak slowly and distinctly.
- Notify the UNICOM station approximately 10 miles from the airport,
reporting altitude, aircraft type, aircraft identification, location
relative to the airport, and whether landing or over-flight. Request
wind information and runway in use.
- Report on down-wind, base, and final approach.
- Report leaving the runway.
(Ground Communications Outlet)
The ground communications outlet (GCO) is a radio transmitter/receiver
with a telephone interface. The GCO allows pilots to communicate
directly with air traffic controllers located at the Patuxent River
Naval Air Station. The GCO at the Captain Walter F. Duke Regional
Airport @ St. Mary’s was provided by the Maryland Aviation
Administration and installed and commissioned in 2004 as a part of a
cooperative effort between Naval Air Station, the Airport Advisory
Committee, and County Airport staff. The system is an affordable way to
access ATC from the ground. By making such remote access available,
pilots won’t have to chose between climbing out of the airplane to make
a phone call or launching into marginal conditions to gain the altitude
needed for radio contact. Pilots must obtain a clearance to depart,
prior to entering clouds or areas of poor visibility (instrument
conditions). Pilots needing a clearance can tune in aviation frequency
121.725 MHz and key their microphone four times. The GCO recognizes the
clicks and automatically dials a restricted number. The pilot then has
the ability to communicate directly with the controller.
How to Use the
1) Pilots on the ground at St. Mary’s should tune a COM radio to
Frequency 121.72 MHz
and slowly click the microphone
times ( ie. one click per second).
2) You will hear approximately two rings of the phone line.
3) A controller from Pax River NAS will answer - you can then begin
4) After you complete your communications, the controller will hang up
and the system will automatically disconnect.
If there is no communication for more than approximately 30 seconds, the
system will automatically disconnect.
PIC (Pilot Information Center)
The Maryland Aviation Administration is initiating a
statewide Pilot Information Center Program for all public use airports.
The PIC will provide on-line services for flight planning, and, flight
plan filing. Pilots will have the ability to access destination airports,
file flight plans, check weather throughout the country, access
navigational maps and other local interest information. Computer terminals
will be in the new terminal building and available for use by everyone in
the general aviation community.
AWOS (Automatic Weather
is a system for automatic acquisition, processing and presentation of
sensor data and is used to generate, edit and distribute meteorological
reports. The AWOS will provide information on wind speed and gusts, wind
direction, air temperature, dew point, precipitation, barometric pressure,
visibility, cloud/ceiling height etc. The sensor data is processed in
accordance with ICAO and WMO regulations. The data is displayed as instant
values in a monitoring window, formatted and automatically assembled into
various reports. The operator can switch the system into a semiautomatic
mode and supplement the automatic data with his/her own observations. All
parameters are stored in a direct access database and can be displayed
graphically. The generated reports (METAR, SYNOP, METREPORT, SNOWTAM,
CLIMATE) are transmitted to a meteorological network (AFTN, METCOM) and
distributed locally (workstations, CCTV). AWOS sends coded messages to
other systems such as the ATIS speech synthesizer or radar processing
units. The AWOS system also allows also for remote control, monitoring and
surveillance of sensors WEBSITE:
http://weather.noaa.gov/weather/current/K2W6.html Frequency: 119.575 MHZ Phone:(301)
Transmission Network (DTN)
The DTN is designed to provide pilots, airports, and FBO’s with
unlimited access to comprehensive satellite aviation weather maps and
flight planning information. METARs, Terminal Area Forecasts (TAFs),
Airmen Meteorological Information (AIRMETs) / SIGMETs, satellite
imagery, weather radar imagery, surface weather imagery, upper air
imagery, 12 & 24-hour significant weather imagery, and city forecasts
are several of the services provided by the system. The system,
located in the
has full color graphics, is equipped with NOAA warnings and alert
module, is AOPA certified, and is automatically updated. Feel free to
access the on-line Help segment for further information and assistance.
Localizer Performance with Vertical
Wide Area Augmentation System (WAAS) - capable
equipment can be used to improve navigation. It is used primarily by
private general-aviation pilots, business and regional aircraft, and
some cargo aircraft. The system includes two geostationary
satellites and a network of ground reference stations that monitor
GPS satellite signals. WAAS corrects for the GPS satellite position
errors, ionosphere delays, and other disturbances in the GPS signals
and warns pilots when the satellites are not functioning correctly
and should not be used for navigation.
In addition to the supporting IFR operations,
WAAS provides for both more flexible approach and departure routings
and more direct, fuel-efficient routings through the air traffic
control system. It also provides an improved navigation source for
other aviation innovations such as terrain avoidance warning systems
and automatic dependent surveillance-broadcast (ADS-B). Using GPS,
an ADS-B–equipped aircraft determines its own position and
periodically broadcasts this position and other relevant information
to air traffic control stations and other aircraft with ADS-B-in
equipment flying in the area. Like the GPS SPS standard, the WAAS PS
defines the WAAS signal-in-space (SIS) characteristics, navigation
message, and performance requirements.
Many view WAAS-LPV as being more economical for piston, turboprop
and smaller jets such as those planned for the St. Mary's Regional
Airport. WAAS-supported LPV approach procedures now surpass the
number of approach procedures of the its ground-based predecessor,
the Category-I instrument landing system (ILS). LPV takes advantage
of the very high performance of the GPS signals when corrected by
WAAS. LPV enables pilots to use instrument flight rules for approach
and landing operations down to a decision height of 200 feet. LPV
approach ceiling minimums are generally 250 feet, with visibility
minimums of 3/4 or 1/2 mile, depending upon runway lighting and
LPV is also designed to provide 16-meter horizontal accuracy and
20-meter vertical accuracy 95 percent of the time. LPV status can
also calls for a 6.2-second time to alert when the system is not
meeting specified requirements. An LPV approach should be published by
the FAA for the St. Mary's Regional Airport by September 2010.