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3. SOP_003 Tower Control Procedures

Tower Control Procedures

 

SOP-003

ZSE Senior Staff

Version 2.1

 

Amended 2019-10-23, changes noted in bold font.

 

1. PURPOSE:

This Standard Operating Procedure (SOP) sets a standard and consistent practices for the operation of tower facilities.

2. ROLES AND RESPONSIBILITIES:

This SOP shall be maintained, revised, updated, or canceled by the ZSE Senior Staff, and shall be effective unless there is a conflict with the VATUSA/VATSIM policies in which case they shall supersede these procedures.

3. DISTRIBUTION:

This SOP is to be read and used by all ZSE controllers.

4. BACKGROUND:

Most towers within a region of VATSIM airspace are unmanned. When a facility such as an Approach Control or Center Enroute Control overlies a field, that facility may be able to provide service for that field. This SOP sets forth a standard procedure for Clearance Delivery, Ground, and Tower services to be provided so that pilots can expect a consistent approach to airport operations.

5. AIRPORT CONTROL PROCEDURES:

a. Real-world periods of operation.

i. For purposes of VATSIM ZSE, air traffic control facilities will not be required to conform to real-world hours of operation. Since many online pilots do not have access to this information, and controllers may wish to operate towers at random hours, any tower with an associated Class D airspace may be opened regardless of the published real-world hours of operation.

b.  Restrictions on operations.

i. As the method of publication varies, and since many online pilots do not have access to this information, for purposes of VATSIM ZSE, no real-world published restrictions, such as noise abatement procedures, aircraft class restrictions, or restrictions on the type of operations will be applicable, unless they are specifically included in SOP_100 or the overlying sector SOP.

ii. To ensure orderly traffic flow, the controller operating the TWR may deny requests for training operations including touch and goes and practice instrument approaches to any aircraft. Controllers are encouraged to provide alternate training locations in the nearby area.

c.  Tower airspace management.

i. Unless otherwise noted in SOP_100, The TWR position shall own airspace 5 miles in radius from the center of the field, from the surface to 2500' above the field elevation. This shall apply to all airports charted as towered within Class B, C, and D surface areas. 

ii. Approach controllers shall instruct aircraft to contact TWR prior to entering the towered owned airspace. The radar handoff feature shall not be used between approach control and TWR.

iii. Certain towers will be given authority to use radar procedures to separate traffic; All Class C and B Towers are assumed to have radar, if a Class D airport is assumed to have radar it will be stated in SOP_100. At those towers where the authority to use radar separation is not given in SOP_100, tower controllers will be responsible for providing traffic separation using non-radar or visual separation methods.

d.  Class B & C tower positions - not manned.

For fields within the surface area of Class B or Class C airspace, when the TWR position is not manned, the overlying approach controller will assume tower management responsibility; If workload does not permit providing these services, the controller may declare the tower "closed" (converting the airspace to Class E "uncontrolled"), but must ensure that all aircraft in the airport area are made aware of the closure and are advised to switch to the advisory frequency.

e.  Class D tower positions - not manned.

For fields within Class D airspace, DEP, APP, and CTR are not required to provide radar services; if the controller chooses not to, he should handle operations at these fields as uncontrolled Class E airports. However, radar controllers are encouraged to operate these towers. If the controller is going to operate the tower, he must ensure that the service is uniform, such that all aircraft in the airport area are made aware that the Class D towers are open.

For "closed" Class D Towers:

VFR aircraft should be instructed to make traffic advisory announcements on the advisory frequency and given a frequency change instruction to do so. 

IFR departures should be given an IFR release and instructed to contact the appropriate radar facility once airborne. 

IFR arrivals should be given frequency change approval and told to "report canceling IFR this frequency" when they are separated from other traffic and established on the final approach course. 

f.   Non-movement areas.

As aircraft surface movement operations on VATSIM are monitored from the radar client, and therefore cannot be observed with high precision, ATC shall not be responsible for aircraft pushbacks, unless the pushback would place the aircraft on a taxiway. Thus ATC shall not clear or approve any pilot request for engine start, pushback, towing, or engine shutdown. Requests for engine starts or pushbacks should be conducted at pilot's discretion only.

g. VFR flight during IMC.

ATC is not responsible to enforce the pilot's adherence to FARs. The final judgment of WX conditions lies with the Pilot In Command. If a VFR pilot attempts to operate at the field during reported instrument meteorological conditions (IMC), ATC should:

Advise that IMC conditions are currently being reported. 

Advise that a Special VFR clearance can and should be obtained (if locally permitted). 

Advise that VFR flight will be at pilot's own risk. 

h. Airport open with no radar service.

When a DEL, GND, or TWR position is operating with no radar facility providing approach/departure services (i.e. the overlying CTR, APP, and DEP are offline) the following special procedures and phraseology must be used (it should be noted that this situation is unique to VATSIM and no valid real-world model exists): 

i. Departure Clearance: The departure control frequency should be omitted from the departure clearance. In its place should be the phrase "Departure Not Online". In addition, the Clearance Delivery function must ensure that departure clearances do not rely on radar vectors or pilot is aware no vectors will be able to be given. "Pilot Nav" SIDs or clearance direct to the standard departure fix should be issued, unless specific instructions are included in the "primary airport" section of the sector SOP. 

ii. Exiting the surface area: When an IFR departure approaches the limit of the Class D airspace, IFR aircraft should be issued the following instructions: 

"Leaving my airspace." 

"Frequency change approved." 

"Resume own navigation." 

"Climb to final altitude at pilots discretion." 

iii. Missed Approaches: Aircraft executing missed approaches within the Class D limits should be instructed to execute the missed approach procedure as published on the IAP chart, but to remain on the Tower frequency and to report at the final fix of the MAP (usually a hold).

i. IFR Preferred departure routes and departure clearances.

i.  Pilots of IFR aircraft filing a flight plan without a SID, or with an inappropriate SID for the active runway plan and/or route, or aircraft class or equipment shall be assigned an appropriate DP unless the pilot has indicated "NO SID" or "NO CHARTS" in his flight plan comments.  If the pilot declines to accept a clearance with the appropriate DP for the runway plan and/or route or if the pilot indicates he does not have charts in his flight plan comments the route assigned shall be "via radar vectors to XXXXX" the transition fix of the appropriate DP and route segment based on the ZSE Preferred Routes listed preferred routes page (https://zseartcc.org/info/prefroutes). If no radar facility is available, use the phrase "direct XXXXX, then as filed".

ii.  IFR Aircraft submitting a flight plan with a route that does not comply with ZSE preferred routes as listed on the preferred routes page (https://zseartcc.org/info/prefroutes) shall be issued a routing including the preferred route segment unless they have filed a route that is equally efficient or of "DIRECT" or "GPS DIRECT". For pilots filing "DIRECT" / "GPS DIRECT", the route assigned shall be "via radar vectors to XXXXX, (the transition fix of the appropriate DP and route segment) direct"  Direct routes should only be given to short, intra-ARTCC flights, otherwise, a route should be provided. If no radar facility is available, use the phrase "direct XXXXX, direct".

iii.  The Controller that issued the amendment to the flight plan shall ensure the pilot's flight plan strip is amended accordingly including adding any assigned DPs.

j. Tower Coordination and Departure Releases

i. TWR shall not use the radar handoff feature with the departure controller. When a positive rate of climb is apparent, TWR shall instruct departing aircraft to contact Departure. Likewise, approach control shall not use the radar handoff feature to pass arrivals to TWR. They shall simply issue a frequency change to TWR frequency. This accurately models the lack of a full radar display terminal in the tower.

ii.   At the request of the departure controller, or as specified by sector SOPs, Tower shall use either "Rolling Calls" or "Release Procedures".

For "Release Procedures" the tower controller shall obtain a release for each IFR departure by sending the following message via text or voice:

Text Example:

SEA_TWR: "QXE253 BUWZO"

SEA_APP: "RELEASED"  or   “HOLD"

Voice Example:

"Seattle Approach, Seattle Tower, Request Release"
"Seattle Approach"
"QXE253, BUWZO"
"Released, MF"
"CN"

 For "Rolling Calls" the tower controller shall notify the radar controller when an   IFR departure is rolling or cleared for takeoff by sending the following message   via  text or voice:

Text Example:

SEA_TWR: "QXE253 BUWZO" (No response is required)

Voice Example:

"Seattle Approach, Seattle Tower, QXE253 BUWZO rolling, MF" (no response is required)

iii.  Releases shall always be obtained for VFR departures from airports within Class B/C surface areas. TWR shall include the direction of flight. The departure controller may respond with restrictions to be issued by TWR to the aircraft. Closed traffic will remain with the TWR controller and does not require a release. If an aircraft wishes to depart the pattern, a Class B/C clearance must be obtained from TWR.

Example:

SEA_TWR: "N464JP S-BOUND  16L"

SEA_APP: "RELEASED AT/BELOW 2500"