Contents:
FAR 91.215 Transponder Requirements; ...Web Radar; ...Radar Facilities; ...Bay Tracon; ...Oakland Center;
...Military Radar; ...ATC radar accountability; ...VFR radar advisories; ...Class B Airspace; ...Class C Airspace;
...Basic enroute procedure; ...The Handoff; ...Operational Procedures; Rules of Thumb;
--Any airborne aircraft with a transponder is required to have it on. Mode C, if available, must be used.
--VFR use requires that Mode C be on when within 30 nautical miles of the primary airport of Class B airspace. See Sectional.
--Mode C is required in Class B airspace, and positive control areas (above 18,000'),
--Mode C is required in Class C airspace and above the lateral limits of the Class C airspace to 10,000'.
--Mode C is required above 12,500', below a positive control area (Classes B and C) if over 2,500' above ground level.
--Mode C is also required within 10 nm or airports at Billings, Montana, and Fargo, North Dakota. (Trivia question)
MODE 1 - military usage
MODE 2 - military usage
MODE 3 - civilian usage
MODE 3/A basic 4,096 code equipment
MODE 3/B not used
MODE 3/C altitude encoder equipment
MODE 4 - military usage
Then there is the occasional older aircraft that will waddle through the system with the old 64 code MARK "X" or
MODE "X" box.
MODE 3A
CODE 1200 through code 1267 are VFR with the vast majority of aircraft simply using 1200.
Codes 1270 through 1277 are allocated to Govt. agencies for use as a ground/surface based alignment of radar systems. These reply on the assigned discrete code 3/A and a special 3/C return not associated with the elevation of the target.
CODE 0000 block has some general usage in the system
CODE 0100 through 0700 are allocated for terminal radar approach control use.
CODE 1000 through 7400 are allocated by ARTCCs.
CODE 7500 = hijack
CODE 7600 = radio failure (NORDO)
CODE 7700= emergency.
MODE 3/C - Altitude encoded signals transmit down to the ground based on as altimeter reading of 29.92. Upon receipt of the signal the ATC computer converts the 29.92 value to actual altimeter setting for the computer area concerned. The computer transmits in 100-foot increments only.
If ATC shows you at 1,500 feet MSL, your aircraft would continue to transmit that value so long as you operated not lower then 1,450 feet and not higher then 1,549 feet.
Weather radar is available at the following sites.
Http://members.aol.com/weathernow/index.html
http://www.geocities.com/CapeCanaveral/6186/index.html
http://www.intellicast.com/weather/usa/radar
http://www.geocities.com/SunsetStrip/7033/weather.html#doppler
http://wxp.atms.purdue.edu/radar.shtml
Oakland Center, Bay Approach, Travis Approach
Some of the radar areas are depicted on charts and some are not. Those depicted require that communications be established or a clearance given be prior to arrival. The San Francisco Class B boundaries and information is shown in blue. An additional 30nm circle around San Francisco requires Mode C operation. The Class C airspace around airports having radar is shown in magenta has a ten mile inner circle in which a call up is required to approach just as though were Class D airspace. The outer 20 mile circle has a permissive call up.
In most situations the frequency and controller for approach or departure will be the same. The call up to approach or departure depends on whether you are coming or going. Your first call is brief, who you are and who you are talking to. If you received your transponder code while on the ground, your call-up gives only your identification and altitude.
The latest version of traffic control (TRACON)radar is the ASR-9. Weather circuits are included into TRACON radars but tends to eliminate airplanes when on. Weather depiction can be turned on but the controllers are not competent to make interpretations. Everything changes with ASR-9. ASR-9 is similar in color and display to aircraft radars. There are six levels of precipitation display. Level three and higher should be avoided by all aircraft. The controller who selects the level 3 key has all precipitation level three and higher shown brightly, levels 1 and 2 are shown at low intensity on the screen. As a pilot who is exposed to weather you should be prepared to ask the controller if he has ASR-9 radar display. Ask how many lights he has available (1 to 6) for light aircraft anything over 1 suggests that landing is a good option. Controller liability makes them generally reluctant to give weather advisories without hedging what they say
Bay Approach is located near hanger 10 at Oakland airport. It has multiple backup computers and two radar antennae. The #1 radar is at Oakland Airport adjacent to runway 29. The backup is at Moffett Field. The primary region of Bay Approach is the San Francisco Class B airspace which overlies the Oakland Class C airspace and part of the San Jose Class C airspace. Some of the sectored frequencies overlap. The call is always, "Bay Approach". The frequencies and sectors are on the sectional's frequencies list and shown in appropriate (blue/magenta) boxes on the San Francisco Area chart.
Oakland Center is based at Fremont on the sectional it is coded as ZOA. It has triplicate back up computers and remote communications lines from the Oregon border to Bakersfield, East to Utah and half way across the Pacific. In many instances you must be at certain minimum altitudes to establish radar contact. You may be able to communicate and still not be high enough to be in radar contact. Each sub-region of Center's airspace has a discrete frequency. ZOA frequencies are not on VFR sectionals.
Most military bases offer civilian radar service. The area may be sectored by frequency. The frequencies are available in the sectional frequency list. Call up would be as, "Travis Approach". Most of these services are limited as to altitudes. If you are climbing, you may well be handed off to ZOA (Oakland Center) after passing through a given altitude.
ATC radar is used by the controllers to expedite the movement of traffic. The system is designed and operates for the convenience of ATC. The individual pilot becomes insignificant and can only be assured of the benefits of radar by being both proficient in communication and aware of the limits of radar. Radar contact occurs when ATC has identified you on the PPI display scope. Radar contact in no way relieves you of your responsibility to see and be seen and to avoid flight into terrain. While you are expected to comply with any assigned headings and altitudes, you are also obligated to question any such assignments that you deem hazardous.
ATC does not provide VFR flights with terrain separation. Terrain avoidance is a pilot responsibility per FAR 91.119. VFR pilots should never expect ATC to provide any warnings about terrain. Night VFR, off-airways, or marginal VFR conditions under FAR 91.103 require special planning.
ATC radar does not show terrain. Blocks of airspace have Minimum Vectoring Altitudes (MVA) that can be displayed. These are IFR altitudes that allow 2000' in mountains and otherwise 1000' terrain clearance. VFR flight below these altitudes is relatively common but radar has no specific knowledge of terrain below the MVA. If you have Mode-C on your transponder radar may have Minimum Safe-altitude Warning (MSAW) or Low-altitude Alert System (LAAS) but this is often MVA and no lower.
Radar advisories can be terminated to VFR flights just on the say-so of the ATC specialist. There are some automatic terminations that apply to IFR flights but can be applied to VFR situations. It is very possible that a VFR flight may just be dropped from the system without the pilot ever being told. You should have some general idea of the region and altitudes for a given radar facility. If you have not been in communications for a while, just ask for a radio check. You may have flown off the scope without being noticed. Never leave a radar communication frequency without advising ATC.
ATC radar facilities primarily provide IFR to IFR separation. Secondarily, they will give VFR traffic advisories, navigational assistance, weather information, vectoring, ground speed and safety precautions as work load permits. The VFR pilot is responsible for traffic avoidance but ATC will "take over" if a collision risk exists. VFR flight following is not a substitute for a clearance into Class B or C airspace. When radar coverage does not reach, flight following ceases. There are no VFR separation standards and altitude bust may result only in ATC giving you the current altimeter setting as a gentle reminder. With sufficient altitude you can get flight following anywhere in the U.S. Even at relatively low altitudes you can get it in the non-Sierra part of California.
Getting a local ATC radar frequency is not always easy for the VFR pilot. It may be listed in a blue box for Class B airspace and a magenta box for a Class C. You may need to request it from a nearby tower or FSS. The FSS frequency may not be the correct one for your sector of radar coverage but it will get you into the system. You could get old IFR charts and plates as a source for radar frequencies. The way you make contact with a radar facility makes an impression that is likely to affect the service you receive. It shouldn't but it does. The initial contact, unlike that to a tower or an FSS, should give only the name of the facility, your full call sign, and possibly "over". You will understand the 'why' of this better if you visit a radar facility. Until then just do it.
When the controller returns your call-up, you give again your full identification, type of aircraft, /(slash code) position (departure point), altitude (final altitude), your destination. To do this well you should practice before initial call-up. Giving the destination lets the controller select a code that lets other controllers up the route know where you are going. The better your flight following radio procedures, the better you will be preparing for your IFR rating and the better overall radar service you will receive.
Under VFR flight following you must be assertive and in charge of your flight. Do not rely on the controller to tell you to climb, descend or make a heading change. You just state that you and doing so, and do it. If it makes a problem for him he will so advise by making a "suggestion". If you get confused or into trouble, admit your difficulty and state your willingness to accept help. 20% of ATC controllers are pilots many at commercial level or better.
The altitude limits of radar means that just when you need it most, it will not be available. Much the same limits exist for radio communications. If you are in conditions that put you both below ATC radar and ommunications, it is time to get on the ground. Many FSS or Flight Watch frequencies can be used through remote outlets where other ATC frequencies are not available. It never hurts to have another radio frequency option along your route.
ATC can cancel VFR advisories/following at any time. Should this occur because of lost radar contact, you should ask for the next available frequency that can resume these services along your route. Most often altitude will be the limiting factor as when flying the Sierras or other remote areas. You can monitor the frequency you just left or expect and get some idea as to the altitudes and conditions experienced by other aircraft. Center frequencies are not usually available to the VFR pilot but can be obtained from IFR charts for VFR use.
Since VFR difficulties can develop into emergencies, a VFR pilot must know how to get ATC radar assistance and its limitations. ATC cannot tell the pilot what to do; the pilot must make all decisions. ATC can advise or suggest only. A pilot can request MSAW (minimum safe altitude warning) or LAAS (low altitude alert system) assistance but beyond that radar is limited by the system display to providing MVA (minimum vectoring altitude) as the 'safe' altitude. An individual controller may not have sufficient knowledge to vector you to successively lower MVA sectors and it doesn't hurt to ask.
Radar call-ups only after initial contact of:
F -faclility
I -identity
O -over…
IPAI/DS (pronounced eye-payds)
I - identification (callsign)
P - position (15mi sw BWI)
A - altitude (level 3000, or 4500 for 7500, etc.)
I - intentions (landing BWI) *OR* D - destination
S - squawk code
or
Use the acronym PACER for just a flight following call-up
P - Position
A - Altitude
C - Conditions (VFR/IFR)
E - en-route
R - Request
Not available to student pilots without instructor endorsement.
Be sure that you initiate Class B airspace communications early enough to avoid entering before getting a clearance to enter. Know your positions and altitudes in relation with the Class B airspace so that no entry will occur prior to entry. If the controller fails to give a clearance to enter, be sure to ask for it and get it, before intruding into the Class B airspace. With the latest Class B and Class C airspace requirements, it is not unusual to have a considerable delay before establishing contact. Controllers are often on the phone or processing data that prevents immediate response. In the LAX area it may take five or more minutes before a busy controller can get to a new arrival. General Aviation IFR/VFR flights can expect few, if any, direct or shortest route flights in Class B airspace.
Procedure
Monitor frequency to determine use. Be sure to remain clear of Class B airspace both horizontally and vertically.
"Bay Approach Cessna 1234X over" If no response, wait 30 seconds and call up again. The controllers are often on the phone or processing data that prevents immediate response. When their work load permits they will say...
ATC: "Cessna 1234X Bay Approach go ahead"
34X: "Cessna 34X Birones Reservoir at 3000 squawking 1200 VFR Concord to Half Moon Bay request flight into the Class Bravo airspace at 3500 enroute"
ATC: "34X Standby for squawk" ( Standby means not to make any response. )
ATC: "34X Squawk 0734 and ident"(Turn X-ponder to STANDBY, reset code, set to ALT, push the IDENT button. )
34X: 34X squawking 0734
ATC: "34X Radar contact" acknowledge with 34X.
ATC: "34X traffic 12 o'clock 1 mile" Navy A7 at 2000 climbing"
34X: "34X negative traffic will accept vectors"
ATC: "34X turn right 340"
34X: "34X right to 340 have traffic"
ATC: "34X with reference to traffic proceed own navigation via G.G. Bridge and shoreline"
34X: "34X own navigation"
Do not enter Class B airspace until you receive a specific clearance to do so. Always write down squawk and frequencies. Always repeat back squawk, frequencies, headings, and directions as much as practical. All assigned altitudes and headings be maintained since traffic clearances are determined thereby.
The Class C airspace system has a ten mile inner circle in which a call up is required to an ATC approach facility just as though it were Class D tower airspace. A Communications is a FAR requirement as is transponder operation in Mode C. The outer 20 mile circle has a permissive call up. Class C airspaces are charted with altitudes in magenta outlines.
Operational procedures
1. Get the ATIS
2. Use the correct frequency
3. Practice for smoothness/accuracy/completeness
4. Check for frequency congestion
5. Full aircraft identification + student pilot
6. Position and altitude
7. Request and expected reporting point
8. Initial Class C airspace call up:
"Podunk approach Cessna 1234X student pilot over."
DON'T ENTER THE Class C airspace UNTIL ACKNOWLEDGED. (No clearance required.)
"34X (position-altitude) with ATIS and full intentions and any special request.
Initial Tower Call-up "Podunk Tower Cessna 1234X student pilot Position at altitude request left base entry for the right will report 2 mile base"
Initial call-up to get into the system before you have a transponder code (squawk)is always:
Blank Approach Cessna 6185K over
If no answer...
Check your radio switches and frequency
Wait 30 seconds and try again
When ATC radar responds they need certain information for their computer.
1. Aircraft type and identification
2. Present position and destination
3. Present altitude and final altitude
4. The ATIS letter if you are inbound for landing
There is a 'canned' procedure for saying this:
Cessna 6185K is a Cessna 150 Walnut Creek
landing Oakland out of one-thousand six hundred
for two thousand five hundred with Alpha
ATC will assign a transponder code:
1. Write down the assigned code
2. Say back the code as...
85K understand squawk 5234
3. Place selector on standby
4. Set in assigned code
5. Place selector on altitude
6. If ATC does not advise in radar contact, say
85K squawking 5234
Occasionally, you may immediately be given a squawk or just to remain clear and standby. Be sure you understand the significance of what ATC says. Normally, you will be assigned a squawk and may or may not be told to IDENT. Do not IDENT unless told to. The IDENT button causes a flashing IDENT to appear on the controllers scope adjacent to your data block. The discrete transponder code does more than just identify the aircraft. It often is used as a destination indicator so that other sector controllers know where you are going.
If the controller says "Radar Contact" acknowledge with your last three call letters. If for some reason no secondary target (transponder) is seen, you may be requested to recycle. This means to reset the numbers perhaps providing better electronic contact.
All instructions, traffic point-outs must be repeated back to the controller in acknowledgment with aircraft identification.
Any changes of altitude or direction must be communicated to ATC authorized by the controller.
When you leave a radar service area the controller will so advise you and ask you to squawk VFR (1200) and approve a frequency change. You must never leave contact with ATC approach/departure without such an approval. If you need to change frequency to contact Flight Watch or an FSS just request a 30 second frequency change. You will be told to report when back on frequency.
The area around a radar facility or antenna is divided into both horizontal and vertical sectors. This means that as you proceed you will be changed from one controller to the next. This is called a handoff The controller will, prior to informing you of the hand off, tell the next controller via phone/computer that you are coming and the particulars about your aircraft and operation. Then he will advise you of who to contact and on what frequency.
Once the controller has completed your data block this information can be passed via computer from sector to sector or between facilities. For this reason the 'handoff' requires a minimum of communications. As you transition from Travis airspace to Sacramento Class C airspace, the controller will say...
"85K contact Sacramento Approach on 118.8"
Acknowledge any handoff by repeating back the place and frequency asignment.
"85K going to 118.5 with Sacramento Approach."
So long as ATC does not bill you for their services, you would be well advised to take every opportunity to add their equipment and skills to your flight safety margin.
VFR Flight advisories are not implemented consistantly from facility to facility across the country. Some facilities are more VFR friendly than others. The more professions your radio procedures the more you increase your likelihood of getting the service you want.
The time of day and week makes a difference. a controller can be handling 2 or 3 frequencies while coordinating a bunch of handoffs an the phone line. Just because the frequency doesn't sound busy, may not be a true indication of what the controller is working with.
Just ask, "XX Center/Approach Cessna 1234X VFR request". If he's busy, he'll tell you! If he says, " 34X go ahead with your request". Be pre-prepared to give your entire request that should include;
A. Aircraft identification, type and equipment
B. Where you are, your altitude, and destination
C. Any other specifics.
Rules of thumb:
--In an airplane don't change a radar frequency without getting the ATC o.k.
--Write down the new ATC name and frequency
--Repeat back the essentials for confirmation
--Set new frequency and establish contact
--Check for congestion before using radio
--You must request any changes of altitude or course while in Class B airspace. You must advise on any changes in altitude or course in Class C airspace or other radar areas when in contact. At any time ATC may assign an altitude and heading for safety purposes. If no such assignment is made you are free to make changes as long as you keep them advised of your intentions.
The radar controller as part of FAA Order 7110.65, Air Traffic Control paragraph 2-16b is required to coordinate with other ATC facilities such as a tower your passage through their areas. You are not expected to obtain your own authorization since it would detract from your ability to maintain radio contact with your primary facility. However, if you have a specific need to contact a facility such as flight watch, FSS, or tower it is appropriate to request a 30 second frequency change for such contact. You must report back on frequency when through.
A radar traffic advisory usually gives a 'clock' direction off your nose, a distance and an altitude. Expect the 'clock' to be wrong by an hour or so. You are unlikely to see any small aircraft beyond 5 miles and in haze the distance may be less than a mile. You immediately advise, "85K looking, 85K have traffic, 85K negative traffic" as appropriate. If you can't find the traffic and feel it constitutes a hazard wait 30 seconds and say, "85K negative traffic, will accept vectors." You do this because ATC may wait too long to give you warning or to turn you. Most often they come back with, "85K traffic no longer a factor". You readback everything a radar controller tells you to do. This procedure is to prevent misunderstandings.
The radar handoff requires that you read back the instructions given and the frequency. If you have been listening to what other aircraft have been told you should be expecting the change. The controller has already
told the next controller/facility, electronically, that you are coming. They are expecting you. Don't be in too much of a hurry. When a break in the frequency occurs the handoff call requires you merely to state, who you are talking to, your identification, and altitude.
You say...
85K to Sacramento Approach on 118.8
You then change frequency to 118.8 and say...
Sacramento Approach Cessna 85K level at five thousand five hundred
Say this every 30 seconds or so until acknowledged. Double check your radio settings and frequency.
There is a procedure for changing from one transponder code to another designed to prevent the inadvertent selection of a restricted code as for Air Force One.
Procedure:
1. Standby
2. Select new code
3. Altitude
Have a pencil ready in your hand you can keep it there while holding the yoke (lefties) or while holding the throttle (righties)
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