Issue # 2003-6
In this Issue:
/F*RTE/ Automatic Dependent Surveillance-Broadcast is a new concept in surveillance technology that is based on Global Positioning System (GPS) data rather than radar-computed positions. Approximately once per second, an ADS-B equipped aircraft transmits its GPS position and other information such as altitude, velocity, identification, and aircraft category via an approved data link. ADS-B transmitters may also be mounted on vehicles to transmit their GPS position, vehicle identification, speed, etc., or mounted to mark obstructions.
ADS-B information may be received and used by a wide variety of applications including:
· Aircraft-to-aircraft display of ADS-B equipped aircraft using a new technology referred to as cockpit display of traffic information (CDTI).
Airport vehicle displays similar
to CDTI that provide equipped vehicles with real time aircraft and
vehicle location information.
Integration into air traffic
control (ATC) automation systems, e.g., ASDE-X, Common ARTS, STARS, and
Micro EARTS as an additional surveillance source providing improved
system accuracy and reliability and also providing surveillance coverage
in non-radar areas.
· Airlines can receive real time positional information for their flights and integrate this into a surface management system for improved gate control procedures.
Overview of ADS-B Concept
FAA's Safe Flight 21 (SF-21) Program is a cooperative effort between
government and industry to develop enhanced air/ground capabilities and
improve safety and efficiency based on evolving communications,
navigation, and surveillance technologies.
Controllers in the Bethel, Alaska, area of the Anchorage Air Route Traffic Control Center (ARTCC) have been using ADS-B as an approved source of ATC surveillance outside radar coverage since January 1, 2001. The SF-21 Capstone Program has equipped over 200 commercial aircraft in southwest Alaska with ADS-B avionics. Plans are underway to expand the area of ADS-B surveillance coverage to other portions of Alaska and further examine the benefits of this new technology.
SF-21 initiative is taking place in the Ohio River Valley. In
partnership with United Parcel Service, Inc. (UPS), SF-21 has begun to
conduct an evaluation of new ADS-B/CDTI concepts involving the entire
fleet of UPS Boeing 757 and 767 aircraft. Because of the higher
concentration of ADS-B/ CDTI equipped UPS aircraft, Louisville
Standiford Airport was chosen for the in-service evaluation of ADS-B/CDTI.
One of the potential benefits for aircrews having a cockpit traffic display is the shared situational awareness with ATC. The impact to controllers and pilots, along with proposed procedures and phraseology, will be analyzed during the evaluations of this technology. Expanded use of ADS-B/CDTI equipment by the aviation community will be influenced by the safety, capacity, and efficiency benefits that result from the use of the equipment.
are underway for the FAA to expand its ground infrastructure to support
the use of ADS-B/ CDTI in other regions, including the east coast and
the area around Prescott, Arizona. In addition, Boeing and Airbus are
equipping all new aircraft with ADS-B transmit capability increasing the
opportunity for ADS-B/CDTI equipped aircraft to see other ADS-B aircraft
The Los Angeles ARTCC has been experiencing a phenomenon in the Southern
California area where aircraft in the high altitude structure report
receiving TCAS resolution advisories (RA) when no other traffic is
present that would explain the occurrence. The Accident Investigation
Division, AAI-100, is leading the effort along with experts from
headquarters, region, field offices and civilian and military agencies,
who are working on discovering what is causing the phenomenon and
thereby how to mitigate its affects.
and pilots are reminded to remain vigilant and comply with the
requirements of the
RA program. It is all too easy to be complacent and respond slowly or
not at all to a situation that may seem to be a false alarm, but bottom
line, no one can say quickly whether or not the RA is a bona fide
response to a possible conflict or merely a phantom. Please treat all
TCAS RA with respect. Do not issue control instructions that are
contrary to an RA the pilot has reported. You may provide traffic
information as appropriate. Additional guidance is included in FAAO
7110.65, paragraph 2-1-27, TCAS Resolution Advisories. (AAT-200)
Strict adherence to specified cutoff dates will ensure that aeronautical
information is published on the desired effective date. (ATA-100)
* Denotes Change Notice (CN). NOTE: There is no CN for Alaskan procedures.
Effective with the
October 30 aeronautical charting cycle, military instrument procedures
will be published in the FAA U.S. Terminal Procedures Publication (TPP).
This change should present no operational impact unless both military
and civil procedures are published for the same airport; e.g. Yuma MCAS/Yuma
International, Sheppard AFB/Wichita Falls Muni, etc. Except when a pilot
requests it, civil aircraft operating into civil airports should not
normally be cleared for military approach procedures. However, civil
aircraft may be authorized military procedures at civil airports for
training (practice approaches).
an instrument approach is required, 14 CFR Part 91,175(a) requires,
"Unless otherwise authorized by the Administrator, when an
instrument letdown to a civil airport is necessary, each person
operating an aircraft, except a military aircraft of the United States,
shall use a standard instrument approach procedure prescribed for the
airport in Part 97 of this chapter." Part 91.175(g) states,
"Unless otherwise prescribed by the Administrator, each person
operating a civil aircraft under IFR into or out of a military airport
shall comply with the instrument approach procedures and the takeoff and
landing minimum prescribed by the military authority having jurisdiction
of that airport."
Only FAA procedures are Part 97 and the source of instrument procedures is identified in parenthesis at the top center of the procedure chart. Civil procedures that meet Part 97 requirements are identified by "(FAA)". Military procedures do not meet Part 97 requirements and are identified by the applicable military service; e.g. "(USAF)", "(USN)", "(USA)". This does not mean in any way that military instrument procedures are inferior or "less safe" than FAA procedures. Military procedures are developed using FAAO 8260.3, United States Standard for Terminal Instrument Procedures, however, they are not regulated under the 14 CFR Part 97 process (e.g., they are not published in the Federal Register, etc.). (ATP-120)
In our continuing efforts to reduce aviation accidents and incidents all
air traffic personnel must remain diligent in the area of issuing bird
advisories to pilots. With our yearly refresher training that addresses
the hazards and preventative measures, we want to ensure that all
personnel clearly understand their responsibilities in this area.
7110.65, paragraph 2-22, Bird Activity Information, directs air traffic
personnel to issue advisory information on pilot-reported,
tower-observed, or radar-observed and pilot-verified bird activity.
Include position, species or size of birds if known, course of flight,
and altitude. Do this for at least 15 minutes after receipt of such
information from pilots or from adjacent facilities unless visual
observation or subsequent reports reveal the activity is no longer a
factor. Personnel are also directed to relay bird activity information
to adjacent facilities and to flight service stations whenever it
appears it will become a factor in their areas.
7210.3, Facility Operation and Administration, paragraph 2-1-15, Bird
Hazards, directs facility managers to establish procedures that will
ensure any bird strikes or trend toward an increase in bird activity on
or around the airport served by the airport traffic control tower are
reported to airport management. Airport management is responsible for
the issuance of NOTAMs when flocks of birds roost on the runways.
Industry receives information on bird hazards through the Aeronautical Information Manual, Chapter 7, Section 4, Bird Hazards and Flight Over National Refuges, Parks, and Forests, and through the Aeronautical Information Publication, Section ENR 5.6, Bird Migration and Areas With Sensitive Fauna. Air traffic controllers are encouraged to review this information.
Keeping all parties involved and informed will help facilitate safer aerodromes, timely reporting, and less structural damage. (ATP-100)
(This article first appeared in the Fall 2000 issue of the Air Traffic Bulletin)
/*T/ FAAO 7110.65, paragraphs 3-9-5 and 3-10-6, provide for the application of anticipated separation for departures and arrivals. A takeoff or landing clearance need not be withheld if the prescribed runway separation will exist when a departing aircraft starts its takeoff roll or when an arriving aircraft crosses the landing threshold. The determination that prescribed runway separation will exist is based on positive control through the issuance of specific instructions to ensure that crossing traffic or other aircraft will not be factors for the landing or departing aircraft.
correctly applying anticipated separation, a controller must recognize
that pilots are listening on the frequency and may try to second-guess
the controller's intentions if the intentions are not clearly specified.
In a recent incident, a controller had assumed that an arriving aircraft
landing on a crossing runway would roll through the intersection prior
to the time that the departing aircraft on the crossing runway began its
takeoff roll. No instruct-ions were issued to the landing aircraft to
proceed through the intersection or to turn off the runway at any
particular exit. As a result, the pilot of the landing aircraft, upon
hearing the issuance of the takeoff clearance to the departing aircraft,
applied heavy braking and tried, unsuccessfully, to stop short of the
It must be emphasized that the above example constitutes an inappropriate and incorrect application of anticipated separation. Action was not taken to ensure that the aircraft would roll through the intersection prior to the time that the departing aircraft began its takeoff roll or exited the runway at a specified point prior to reaching the intersection. A correct application of anticipated separation is predicated on the issuance of specific instructions with acknowledgements, if appropriate, so that the controller can ensure that all potential conflicts will be resolved and that all pilots understand and have acknowledged their instructions.
As the example
highlights, basing separation on assumed actions of pilots may lead to
undesirable results. In conclusion, anticipating separation is not
assuming that separation will exist; anticipating separation is
exercising positive control actions to ensure that the prescribed
separation will exist. (ATP-120)
One of a pilot's
greatest concerns about flying a single-engine airplane at night is the
possibility of a complete engine failure and the subsequent emergency
landing. Even though flight into adverse weather and poor pilot judgment
account for most serious accidents, night emergencies are always very
serious events. Controllers should be aware of important pilot
procedures and considerations for dealing with night engine failure and
other similar emergencies.
advised of a night engine failure, controllers should be aware that
pilots must maintain positive control of the airplane. Pilots should
establish the best glide configuration and airspeed. Controllers can
sometimes assist the pilot in turning toward an airport, away from
congested areas or away from mountainous terrain. Surface wind direction
and speed information is important to a power-off aircraft landing at
night since a downwind landing should be avoided.
should obtain enough information to handle the emergency while the
aircraft is still in radio and radar contact. Remember, the pilot is
authorized by 14 CFR Part 91 to determine a course of action but
controllers can get help on the way before the landing is completed.
Sometimes pilots will communicate with ATC after an emergency landing,
however the Airplane Flying Handbook recommends that the pilot turn off
all switches and evacuate the aircraft as quickly as possible.
FAAO 7110.65 reminds controllers, "because of the infinite variety
of possible emergency situations, specific procedures cannot be
prescribed. However, when you believe an emergency exists or is
imminent, select and pursue a course of action which appears to be most
appropriate under the circumstances and which most nearly conforms to
the instructions in this manual." (ATP-120)
are a critical link in the ATC system. The link can be a strong bond
between pilot and controller or it can be broken with disastrous
results. FAAO 7110.65 provides standard ATC phraseology for providing
ATC services. Good communications or phraseology enhances safety.
Therefore, we encourage controllers to speak at a reasonable rate and to
use standard phraseology when communicating with all flight crews,
especially those whose primary language is not English. (ATP-120)
/*T/ FAA Flight Standards Service (AFS) recently revised two Advisory Circulars (AC) pertaining to pilot procedures during taxi operations. The AC numbers are AC 91-73A, Part 91 and Part 135, entitled Single-Pilot Procedures During Taxi Operations and AC 120-74A, Parts 91, 121, 125, and 135 entitled Flightcrew Procedures During Taxi Operations. Both ACs are dated 9/26/03 and are located at: http://www.faa.gov/regulations/guidance.cfm"
The purpose of the ACs is to provide guidelines for the development and implementation of standard operating procedures for conducting safe operations during taxiing. The ACs are intended for use by pilots. However, controllers are encouraged to review these ACs to enhance awareness and to strengthen the controller-pilot communications link. Below are just a few of the revisions to AC 120-74A. Similar revisions are also contained in AC 91-73A.
Paragraph 6c (2) (c),
Flightcrews should be especially vigilant when instructed to taxi into "position and hold," particularly at night or during periods of reduced visibility. They should scan the full length of the runway and scan for aircraft on final approach or landing roll out when taxiing onto a runway either at the end of the runway or at an intersection. ATC should be contacted any time there is a concern about a potential conflict.
In instances where flightcrews have been instructed to taxi into "position and hold" and have been advised of a reason/condition (wake turbulence, traffic on an intersecting runway, etc.) or the reason/condition is clearly visible (another aircraft that has landed on or is taking off on the same runway), and the reason/condition is satisfied, they should expect an imminent takeoff clearance, unless advised of a delay.
If landing traffic is a factor, the tower is required to inform flightcrews when clearing them to taxi into "position and hold" of the closest traffic that is cleared to land, touch-and-go, stop-and-go, or unrestricted low approach on the same runway. Flightcrews should take care to note the position of that traffic and be especially aware of the elapsed time from the "position and hold" clearance while waiting for the takeoff clearance.
ATC should advise
flightcrews of any delay in receiving their takeoff clearance (e.g.,
"expect delay for wake turbulence") while holding in position.
If a takeoff clearance is not received within a reasonable time after
clearance to "position and hold," ATC should be contacted.
Suggested phraseology: (call sign) holding in position (runway
designator or intersection). Example, "American 234
holding in position runway 24L," or "American 234
holding in position runway24L at Bravo."
Paragraph 6f (5) (a)
(b), page 9.
Flightcrews should read back all clearances/ instructions to enter a specific runway, hold short of a runway, and taxi into "position and hold," including the runway designator. Pilots should not merely acknowledge the ATC instruct-ions or clearances to enter a specific runway, hold short of a runway, and taxi into "position and hold" by using their call sign and saying "Roger" or "Wilco." Instead they should read back the entire instruction/clearance including the runway desig-nator. Air traffic controllers are required to obtain from the pilot a readback of all runway hold short instructions. (FAAO 7110.65 paragraph 3-7-2d.)
Paragraph 8b (4) (5),
pages 14 –15.
When entering a runway either for takeoff or when taxiing into "position and hold," flightcrews should make their aircraft more conspicuous to aircraft on final behind them and to ATC by turning on lights (except for landing lights) that highlight the aircraft's silhouette. Strobe lights should not be illuminated if they will adversely affect the vision of other pilots.
Additionally pilots are
advised to turn on landing
lights when takeoff clearance is received, or when commencing
takeoff roll at an airport without an operating control tower. (ATP-120)
controlled operation of an apparatus, process, or system by mechanical
or electronic devices that take the place of human organs of
observation, effort, and decision.
· Ergonomics: An applied science concerned with the characteristics of people that need to be considered in designing and arranging things that they use in order that people and things will interact most effectively and safely.
the past 10 years or so, controllers have seen an increase in new
equipment introduced into their facilities. The equipment provides more
information to controllers, automates some functions, and presumably,
overall makes the controller's job easier. When new equipment arrives,
the old equipment and ways of operation are often discarded as
"antiquated" or no longer necessary. In many cases this is
true, however, in some cases the total replacement of an old, hallowed
way of doing business or piece of equipment may not help everyone as
much as the designers or the facility had expected.
is the case with clothing styles, cars and the like, one size does not
always fit all.
example, DSR and STARS equipment have many automated functions.
Information can be acquired by a single or series of key strokes or the
use of the mouse/slewball. For some people, this method of access works
like a charm and seems quite natural, but for others, it could be a
distraction when compared to the "old way" of accessing the
information. For example, a single glance at a paper flight progress
strip, or "cheat sheet" posted at the position as compared to
accessing a computer
you have a choice, obviously, you will use the method that is most
beneficial to your style of work. Matching styles of work with the
equipment can help to avoid mistakes. An example of such ergonomics
might be the simple design where an aircraft's mixture control knob is
knurled and red in color and the throttle is smooth, somewhat larger and
black in color. This helps the pilot identify the correct knob by both
the sense of touch and sight.
You can probably come up with other better examples where equipment has been designed to better fit the person using it so that no injury results in using it, it is intuitive or natural to use, or again, its use is better protected against inadvertent application. Another example might be whether a work station can be set up for right- or left-handed persons. It is to your advantage to recognize and use the tools and methods that best suit you.
course, when new systems replace old ones, the option of continuing to
use what worked well for you in the past may be severely limited. So,
what can you do? Probably, the best option may be to become as
proficient as possible using the new system. Now you might think,
"Oh, that's so obvious it's stupid of the writer to mention
have to wonder though, could the reason some individuals are surprised
by an aircraft's "sudden" turn at a point on its route be
because the individual doesn't know that the aircraft will change
direction at that point? Could the reason that the individual does not
know this will happen be due to a reluctance to use the equipment
options because of a lack of comfort, knowledge, or expertise in using
the equipment? If this is the case, then the individual will prefer to
work "in the dark," banking on his/her ability to keep track
of the traffic by solely scanning the scope. By choosing this method,
the individual may feel that he/she will not incur the stress or worry
of getting behind or disrupting his/her concentration by trying to make
various fancy computer entries. The "in the dark" methodology
is probably more prevalent than you may think. Bottom line, it doesn't
always work well.
Here we might take a lesson from our piloting friends. Pilots learn to deal with certain emergencies and procedures by employing a learning technique called, "over learning." That is, they practice the sequence of movements in the cockpit so frequently that they become totally automatic. This means that when a certain situation occurs, the subsequent actions are accomplished quickly and accurately without conscious thought. The concept of over learning can easily be demonstrated by learning to drive a stick shift automobile. When first attempted, the driver has to concentrate to get the sequence of clutch, shift, and power worked out. Once learned, however, the driver no longer needs to give the action any more thought than I want to go, or slow, or stop. Period. Once the over learning process has been completed, the driver may be asked to give directions to the post office or name the moons of Jupiter, and although much thought may go into naming the moons, no thought will be wasted on shifting the car's gears . . . that will happen effortlessly.
of the controller errors that seem inexplicable may be due, in part, to
too much conscious thought having to be devoted to certain actions. For
example, a very experienced controller climbs or descends an aircraft
right through another that is within 10 miles on converging courses,
having completely overlooked that aircraft, or failed to realize that it
will change its course at the next intersection or NAVAID and it will
become a threat to another aircraft. If your short-term memory is full
of bits of information or actions/thoughts that could be relegated to
the over learning process, you are likely experiencing a temporary
short-term memory overload, and yes, you forget stuff. The more actions
that you can commit to long-term memory where the over learning is
maintained, the better off you will be in heading off short-term memory
overload. This is where your ability to quickly access information
through your position's automation without a lot of conscious thought is
to your advantage.
from over learning, there may be additional ways to enhance your ability
to keep track of your position's demands. For some, it could be as
simple as a pad of paper and a pen or pencil for short, cryptic notes
that help you avoid silly mistakes due to faulty recall or inadvertent
forgetfulness. It should go without saying that any visual memory
joggers or tools that you employ must be scanned (glanced at and read)
frequently to refresh your short-term memory. That is what such tools
are designed to do. Other techniques are the particular physical
placement of a flight progress strip holder. Think about it and see if
there might be ways to enhance your ability to do your job and make the
most of the equipment you have to help you do it. Think about your own
ergonomic design needs and how you can best enhance your working
relation-ship with the automation in your life.
VFR tower controller's area of major responsibility is generally defined
by whether or not standard separation is maintained on the runway
surface environment. Obviously, if the standard is not maintained, an
incident or accident will be the result. The FAAO 7110.65 states that
the "primary purpose of the ATC system is to prevent a collision
between aircraft operating in the system and to organize and expedite
the flow of traffic." To that end, numerous tools and procedures
have been developed and controllers trained to use them to provide good,
Each facility has its responsibilities defined as to what and where separation must be assured. Except in certain circumstances, most airborne aircraft will be provided some form of separation services in the form of a separation standard that the controller is required to provide. However, the VFR tower controller is taxed with providing separation primarily in and around the runway environment. Since the primary purpose of ATC is to prevent collisions in the system, how does the lack of a "standard separation" in the traffic pattern square with the primary purpose?
term, VFR tower, helps explain this. Pilots are required to use
visual flight rules when flying in the Class D airspace and
subsequently, in the airport traffic pattern. Those large windows in the
VFR tower building give the control specialist a good viewing platform
from which to oversee the pilots. Traffic advisories, safety alerts, and
some control instructions are all methods that the controller can use to
help the pilot maintain safe operations and thereby prevent collisions.
The following are a few tips and techniques that can help a controller
be more effective in achieving both goals. Please note that a BRITE
radar is not necessary to be successful. It is a tool that is helpful
for telling a controller what direction and range to expect when
beginning the visual search for the aircraft through the tower windows.
Locate the aircraft visually (out
the window) as soon as possible and as far away from the airport as
possible. This is always to your advantage.
If available, use the BRITE to
show you in what direction to look and what range,
then . . .
Locate the aircraft by looking out
the window using . . . the naked eye AND the
for visually sighting aircraft:
Based upon the pilot's position
report, consciously look long range, mid range, or short range. Do not
just look out of the window. Your eyes will not focus to a long range
without conscious effort but more to a medium-short range, which will
not be effective.
If the aircraft is 5 miles or more
away, start at the horizon and work your way from left to right or vice
versa, including an upward scan block by block in a grid pattern,
slowly. Be sure to stop your eye movement and peer straight ahead
momentarily before continuing your scan at frequent intervals.
This is very useful for detecting movement. What you are looking
for is a speck moving across your field of vision. When you sense
movement, focus on it to determine whether or not it is your aircraft.
If a bird has caught your attention due to its movement, then you know
that you have been focusing in too close. If the squashed fly on the
window shade catches your attention, you are really focusing too close!
In both cases, adjust your focus accordingly.
If the aircraft is closer than 5
miles you should begin your search slightly higher above the horizon.
NOTE: If the aircraft is closer than 5 miles, begin your search much
more above the horizon. If the aircraft is 3 miles or closer, begin your
search at the runway threshold and work your way outward. Always think
about searching the area nearest the threat area. The threat area could
be another aircraft's flight path or the runway. The closer an aircraft
is to you, the higher in the sky it will appear EXCEPT for aircraft on
short final, flying a low, flat approach. A good technique to help train
your eye is to search for aircraft that report at a known distance. For
example, the final approach fix for an instrument approach will have the
aircraft at a specific altitude and range, which is ideal for practice.
If an aircraft has distance measuring equipment (DME) and so does your
localizer or VHF omni-directional radio range (VOR), you can ask the
pilot to report the aircraft's DME position and then remark to yourself
what the aircraft looks like at that distance and altitude. Practice
finding it with the binoculars and then your naked eye.
Once the skill of accurately
adjusting your vision to near, medium, and far is mastered, you will be
able to adjust it rapidly as you scan. You should be able to do this
with the binoculars alone as well as only your naked eye.
When the aircraft is sighted
through binoculars, find it with the naked eye by moving the glasses
downward from the aircraft to the horizon. Remove the glasses and, using
the horizon or object on the horizon (water tank, building, tree, etc.)
as a guide, move upward to attempt sighting the aircraft. Take care that
you maintain the same focus for the distance to find the aircraft. If
you cannot see the aircraft with your naked eye, come back with the
binoculars a little later and repeat the exercise.
Sighting aircraft may be enhanced
if you know ahead of time what to expect it will look like. An
aircraft's appearance will depend upon the lighting conditions and sky
background. Sometimes aircraft will appear white, silver, black, or grey
at a distance. Learn which color should be expected with each
meteorological condition. This will help you find aircraft at a further
distance from the airport.
The longer you have to observe an
aircraft, the better you will be able to judge its speed and how and
where it will enter your pattern. This information will assist you in
judging its sequence with other aircraft as well as determining what
traffic information will be useful to the pilot for collision avoidance.
A busy local controller will often
work aircraft with the binoculars and pencil in one hand and the mike
switch in the other, or frequently pick up the binoculars throughout the
· Be careful not to use the binoculars exclusively, because they narrow your line of sight and do not have the greater peripheral vision that your naked eye has. Use them a lot, but you will need your unencumbered eyes to keep track of aircraft on the runway and taxiways and in the traffic pattern.
Note: The distances of 5- and 3-mile guidelines are approximate. Generally, the further away an aircraft is, the lower is will appear on the horizon. Conversely, the closer it is, the higher it will appear. (AAT-200)