Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 31
1.3.5.3 Databases
The EGPWS contains the following types of databases, which can be loaded via the EGPWC front panel PCMCIA interface
independent of the system software. Updates to each database will be made available.
Envelope Modulation Database (see section 6.8)
Terrain Database (see section 6.7.5), which also contains the Runway Database (see section 6.3.1.2) and may
also contain an Obstacle Database (see section 6.7.6).
1.3.6 System Limitations
The performance of the EGPWS terrain protection is limited for areas where terrain data is not available, or where
navigational accuracy is degraded. Terrain data or runway location data may have errors inherent in the source of such data.
Such errors can delay a terrain alert, or may cause unwanted alerts. Such errors do not affect the basic GPWS functions.
The terrain display is to be used to enhance situational awareness only, and is not to be used for navigation or escape
guidance.
The basic GPWS function relies on the downward-looking radio altimeter and cannot sense forward terrain. Therefore
warning times for flight into precipitous terrain with little or no preamble terrain can be very short. An alert may not be
provided for stabilized flight in full landing configuration into a place where there is no runway, and where neither Mode 6
nor the Terrain Clearance Floor function nor the Terrain Awareness function has been enabled.
Terrain clearances or descent rates during radar vectoring that are not compatible with those required by the GPWS Minimum
Operating Performance Standards (TSO-C92c, TSO-C151a and CAA Spec 14) may cause unwanted alerts.
1.3.7 Installation Procedures and Limitations
The technical data shall be sufficient to ensure that the article, when installed in accordance with the installation procedures,
continues to meet the requirements of the TSO. The limitations shall also be sufficient to identify any unique aspects of the
installation. The limitations shall include at least the following:
“The TSO identifies the minimum performance standards, tests, and other conditions applicable for issuance of
design and production approval of the article. The TSO does not specifically identify acceptable conditions for
installation of the article. The TSO applicant is responsible for documenting all limitations and conditions suitable
for installation of the article. An applicant requesting approval for installation of the article within a specific type or
class of product is responsible for determining environmental and functional compatibility.”