A320 flight crew reported receiving a terrain warning on approach geg airport.

Attributes
ACN	1654758
Time
Date	201906
Local Time Of Day	0601-1200
Place
Locale Reference	GEG.Airport
State Reference	WA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

Day VMC; terrain in sight; visual approach to geg runway 26 backed up by RNAV GPS Y 26. Flying direct to naxaf from an ATC radar vector. Approximately 7;000 feet and over higher terrain. Started a descent to naxaf to 5;200 feet when we were past (backside) of high terrain. Received a momentary (one aural annunciation) GPWS warning for terrain. Even though we were day VMC and in sight of terrain; I initiated the GPWS escape maneuver and we notified ATC of the event. We climbed to approximately 7;000 feet. Assured we were clear of terrain; we resumed descent to visual/normal/stabilized landing.we were descending away from high terrain. I knew the altitude from hilie to cugev was 6;700 feet and planned my descent to not go below that altitude until clear of terrain. We were flying direct to naxaf so cugev was removed as a reference point for descent. At some point we were low enough to briefly trigger the GPWS. We both were in terrain mode and did not receive any terrain caution before the terrain warning. Also; the terrain presentation on the 320 basic aircraft is very difficult to see in bright sunlight. We would have had better backup to our visual clues if the terrain presentation on the navigation display wasn't so weak.better awareness of the possibility of a GPWS warning when visual approach to runway 26. Don't descend until past cugev.

Original NASA ASRS Text

Title: A320 flight crew reported receiving a TERRAIN warning on approach GEG airport.

Narrative: Day VMC; terrain in sight; visual approach to GEG Runway 26 backed up by RNAV GPS Y 26. Flying direct to NAXAF from an ATC radar vector. Approximately 7;000 feet and over higher terrain. Started a descent to NAXAF to 5;200 feet when we were past (backside) of high terrain. Received a momentary (one aural annunciation) GPWS warning for terrain. Even though we were day VMC and in sight of terrain; I initiated the GPWS escape maneuver and we notified ATC of the event. We climbed to approximately 7;000 feet. Assured we were clear of terrain; we resumed descent to visual/normal/stabilized landing.We were descending away from high terrain. I knew the altitude from HILIE to CUGEV was 6;700 feet and planned my descent to not go below that altitude until clear of terrain. We were flying direct to NAXAF so CUGEV was removed as a reference point for descent. At some point we were low enough to briefly trigger the GPWS. We both were in terrain mode and did not receive any terrain caution before the terrain warning. Also; the terrain presentation on the 320 basic aircraft is very difficult to see in bright sunlight. We would have had better backup to our visual clues if the terrain presentation on the navigation display wasn't so weak.Better awareness of the possibility of a GPWS warning when visual approach to Runway 26. Don't descend until past CUGEV.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.