Section 4. TPX-42

11-4-1. OPERATIONAL USE

a. Do not use TPX-42 data when the system is released to Technical Operations technicians.

b. Verify the operational status of the TPX-42 prior to operational use.

c. Inform affected facilities of scheduled and unscheduled shutdowns.

d. Develop local procedures, operating instructions, and training materials required to ensure intrafacility standardization of operation.

e. Facility directives must specify the discrete codes assigned to each operating position from the code subsets allocated to the facility.

f. Traffic entering the terminal airspace on an ARTCC computer-assigned discrete beacon code must not remain on that code any longer than the time specified in a LOA.

NOTE-
Center computer parameters are adjusted to minimize the time in which a discrete code is assigned to an aircraft. The time specified in the letter of agreement should not exceed the Arrival Flight Plan Drop Interval adapted for your airport.

11-4-2. LOW ALTITUDE ALERT SYSTEM (LAAS)

a. When continued use would adversely impact operational priorities, air traffic managers may temporarily inhibit the LAAS. Except when equipment or site adaptation problems preclude the use of LAAS, a brief written report must be sent to the respective Terminal Operations Service Area Office whenever it is inhibited. A copy of the report must be sent to System Operations and Safety, System Safety and Procedures.

b. Air traffic managers are authorized to inhibit LAAS at specific operating positions if an operational advantage will be realized.

c. Sector/altitude maps must be kept current.

d. Terminal Operations Service Area Offices must:

1. Furnish LAAS facilities a copy of:

(a) Newly received FAA Form 7460-2, Notice of Actual Construction or Alteration.

(b) Emergency Notices of Construction of structures more than 200 feet above ground level lying within 60 NM of the radar site.

2. Ensure that the daily National Flight Data Digest is provided to LAAS facilities when it affects their area of jurisdiction.

e. Facility managers must ensure that:

1. The material described in subpara d1 above, is reviewed, and that the appropriate corrections to the sector/altitude map are made.

2. The magnetic variation of the facility's sector/altitude map coincides with the magnetic variation of the facility's radar video maps/geo maps.

NOTE-
The sector/altitude map is constructed to align with the radar antenna offset for magnetic north. Consequently, any change in antenna offset will result in a corresponding change in the relative position of the terrain points and the obstacles used to determine altitude assignments. This will require generating a new sector/altitude map.