ZLC controller described a failed communications attempt with gpi tower by an IFR inbound on the loc...

Narrative:

An air carrier was cleared for a localizer runway 2 approach to the glacier park international airport; subsequently; radar service was terminated and the air carrier was advised to contact glacier tower on 124.55. Two minutes later; the air carrier came back on center frequency and said tower did not respond. I attempted to contact tower on the shout line with no success. The area supervisor was notified and he attempted to call the tower via the telephone line with no success. The air carrier landed on runway 2 without clearance from tower. The air carrier cancelled IFR on center frequency. Five minutes later tower called on the shout line and said the air carrier was an arrival and when I asked if everything was okay; he said everything was fine.

Original NASA ASRS Text

Title: ZLC Controller described a failed communications attempt with GPI Tower by an IFR inbound on the LOC Approach. The reporter was unable to explain the failed communications.

Narrative: An Air Carrier was cleared for a LOC Runway 2 approach to the Glacier Park International Airport; subsequently; RADAR service was terminated and the Air Carrier was advised to contact Glacier Tower on 124.55. Two minutes later; the Air Carrier came back on Center frequency and said Tower did not respond. I attempted to contact Tower on the shout line with no success. The Area Supervisor was notified and he attempted to call the Tower via the telephone line with no success. The Air Carrier landed on Runway 2 without clearance from Tower. The Air Carrier cancelled IFR on Center frequency. Five minutes later Tower called on the shout line and said the Air Carrier was an arrival and when I asked if everything was okay; he said everything was fine.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1045343
Time
Date	201210
Local Time Of Day	0001-0600
Place
Locale Reference	GPI.Airport
State Reference	MT
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Procedural Landing Without Clearance Deviation - Procedural Published Material / Policy

ZLC controller described a failed communications attempt with gpi tower by an IFR inbound on the localizer approach. The reporter was unable to explain the failed communications.