Section 4. TPX-42
11-4-1. OPERATIONAL USE
a. Do not use TPX-42 data
when the system is released to Technical Operations
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
e. Facility directives must
specify the discrete codes assigned to each operating
position from the code subsets allocated to the
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.
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
b. Air traffic managers are
authorized to inhibit LAAS at specific operating
positions if an operational advantage will be
c. Sector/altitude maps must
be kept current.
Operations Service Area Offices must:
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
1. The material described in
subpara d1 above, is reviewed, and that the
appropriate corrections to the sector/altitude map are
2. The magnetic variation of
the facility's sector/altitude map coincides with the
magnetic variation of the facility's radar video
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.