Narrative:

Enroute to skrg we briefed the marinilla one alfa arrival to the ILS runway 36 approach. Initial descent was uneventful and we were cleared as expected to descent to 12;000 ft MSL. Due to thunderstorms over mrn and in the vicinity if the airport; deviations west of course were needed to avoid the weather. As a result of our deviations approach control revised our descent clearance to 13;000 ft MSL. After clearing the weather over mrn; we were instructed to rejoin the arrival 5 south of mrn; which we did and were subsequently recleared to 12;000 ft MSL. Due to the weather I was in weather radar and the first officer was in terrain at this point. LNAV was used with VNAV then vertical speed when approaching rng. Prior to rng we were recleared the mrn 1A arrival and the ILS 36 approach. Prior to rng we were configured at flaps 5 and 180 KTS. At this point approach held us at 12000 ft MSL for passing traffic at 11;000 ft MSL. Once past the traffic and outbound from rng we were cleared to 11;000 ft MSL and recleared for the mrn 1A to the ILS 36. We began the descent to 11;000 ft MSL then upon passing the outbound fix rng 215/7DME as per the arrival began a descent to the published altitude of 10;000 ft MSL. At this point weather was no longer a factor and I switched to terrain. We were about to rollout of the turn inbound on the rng 180R the rdr altitude came alive followed shortly thereafter by an automated terrain warning 'terrain terrain pull up pull up.' no terrain was shown on the displays just the pull up warning. I added power and pitch for the escape maneuver but the instant I did the warning had ceased and we had only climbed 150 ft; so confident we were where we were supposed to be (on the magenta line and at the correct altitude) and VFR (night); we resumed the arrival and completed the approach uneventfully. Worthy of note here is that the ILS 36 holding pattern procedure turn has a alt restriction when inbound to rng on the 185R to maintain 11;000 ft MSL until 5 DME then 10;000 ft MSL til rng. We followed our clearance (mrn 1A) and procedures to the letter and still got a GPWS alert. I feel this discrepancy between the ILS 36 procedure and the mrn 1A arrival warrants some review so other crews don't get that spine chilling spurious GPWS alert.

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Original NASA ASRS Text

Title: Air carrier Captain experienced GPWS warning while descending to 10;000 FT at night on the MRN 1A arrival to SKRG. Warning ceased the moment the nose was raised to escape and the flight continued to landing.

Narrative: Enroute to SKRG we briefed the Marinilla One Alfa arrival to the ILS Runway 36 approach. Initial descent was uneventful and we were cleared as expected to descent to 12;000 FT MSL. Due to thunderstorms over MRN and in the vicinity if the airport; deviations west of course were needed to avoid the weather. As a result of our deviations approach control revised our descent clearance to 13;000 FT MSL. After clearing the weather over MRN; we were instructed to rejoin the arrival 5 south of MRN; which we did and were subsequently recleared to 12;000 FT MSL. Due to the weather I was in weather radar and the First Officer was in terrain at this point. LNAV was used with VNAV then vertical speed when approaching RNG. Prior to RNG we were recleared the MRN 1A arrival and the ILS 36 approach. Prior to RNG we were configured at Flaps 5 and 180 KTS. At this point approach held us at 12000 FT MSL for passing traffic at 11;000 FT MSL. Once past the traffic and outbound from RNG we were cleared to 11;000 FT MSL and recleared for the MRN 1A to the ILS 36. We began the descent to 11;000 FT MSL then upon passing the outbound fix RNG 215/7DME as per the arrival began a descent to the published altitude of 10;000 FT MSL. At this point weather was no longer a factor and I switched to terrain. We were about to rollout of the turn inbound on the RNG 180R the RDR ALT came alive followed shortly thereafter by an automated terrain warning 'TERRAIN TERRAIN PULL UP PULL UP.' No terrain was shown on the displays just the pull up warning. I added power and pitch for the escape maneuver but the instant I did the warning had ceased and we had only climbed 150 FT; so confident we were where we were supposed to be (on the magenta line and at the correct ALT) and VFR (night); we resumed the arrival and completed the approach uneventfully. Worthy of note here is that the ILS 36 holding pattern procedure turn has a Alt restriction when inbound to RNG on the 185R to maintain 11;000 FT MSL until 5 DME then 10;000 FT MSL til RNG. We followed our clearance (MRN 1A) and procedures to the letter and still got a GPWS alert. I feel this discrepancy between the ILS 36 procedure and the MRN 1A arrival warrants some review so other crews don't get that spine chilling spurious GPWS alert.

Data retrieved from NASA's ASRS site as of April 2012 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.