During approach to bzn; aircrew experienced a GPWS terrain warning and executed the escape maneuver.

Attributes
ACN	1327187
Time
Date	201601
Local Time Of Day	1801-2400
Place
Locale Reference	BZN.Airport
State Reference	MT
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Make Model Name	Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Descent
Flight Plan	IFR
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 96 Flight Crew Type 771
Person 2
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 179 Flight Crew Type 5435
Events
Anomaly	Inflight Event / Encounter CFTT / CFIT

Narrative:

We were descending into bozeman at night time. We were in IMC and cleared from lvm to kidco to begin the ILS 12 approach. We were cleared to 11000 after crossing lvm. Shortly before leveling at 11000 feet the radar altimeter began counting down from 2500 feet and the aural 2500 sounded. At about 11100 feet; 'terrain; terrain; pull up' sounded. The captain immediately executed the terrain avoidance maneuver. After climbing to about 15000; we informed ATC and they cleared us to 10100 and cleared us for the approach. ATC did not seem to be concerned about our situation. There was no terrain displayed on the nd at any point during the descent and subsequent terrain warning. We executed the ILS 12 and landed with no further issues. There happened to be a deadheading pilot on the flight and he told us later that that was the third such situation he has heard of in the past year flying into bzn.

Original NASA ASRS Text

Title: During approach to BZN; aircrew experienced a GPWS terrain warning and executed the escape maneuver.

Narrative: We were descending into Bozeman at night time. We were in IMC and cleared from LVM to KIDCO to begin the ILS 12 approach. We were cleared to 11000 after crossing LVM. Shortly before leveling at 11000 feet the radar altimeter began counting down from 2500 feet and the aural 2500 sounded. At about 11100 feet; 'terrain; terrain; pull up' sounded. The captain immediately executed the terrain avoidance maneuver. After climbing to about 15000; we informed ATC and they cleared us to 10100 and cleared us for the approach. ATC did not seem to be concerned about our situation. There was no terrain displayed on the ND at any point during the descent and subsequent terrain warning. We executed the ILS 12 and landed with no further issues. There happened to be a deadheading pilot on the flight and he told us later that that was the third such situation he has heard of in the past year flying into BZN.

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.