Air carrier on approach to ktn and on ktn radio's frequency elects to change from RNAV to ILS approa...

Narrative:

Cleared by anc ATC for RNAV 11 approach into ktn. While on downwind; a fog bank began rolling over the airport as reported by ktn radio. During the base turn we could see the approach end of the runway; but just barely. During the turn to final; we decided to change to the ILS and expressed our desire to ktn radio. They cleared us for it; and we engaged the approach mode of the autopilot. We had briefed it during the decent as well just in case. I put it into the FMC and we continued to the DH. We could see the approach lights but not the runway; so we executed a missed. Realizing we were on a different misssed approach in direction of hold; we made sure we told anc ATC when we contacted them that we were on the missed approach from the ILS; not the RNAV. Just before entering the hold; anc ATC informed us of an altitude limit that they had that prevented them from giving us a late clearance for the ILS; but we thought ktn radios approval of the approach was good enough. The anc controller said it was pretty much for information only; but providing this report may help other crews in the future. Cause; misunderstanding of who can clear us for approaches. We thought ktn radio could change us from the RNAV to the ILS. Suggestions; fly the approach you are last cleared for; do the missed approach if required; then try another approach.

Original NASA ASRS Text

Title: Air carrier on approach to KTN and on KTN radio's frequency elects to change from RNAV to ILS approach ending in a missed approach procedure prompting questions regarding clearance procedure change authority.

Narrative: Cleared by ANC ATC for RNAV 11 approach into KTN. While on downwind; a fog bank began rolling over the airport as reported by KTN radio. During the base turn we could see the approach end of the runway; but just barely. During the turn to final; we decided to change to the ILS and expressed our desire to KTN radio. They cleared us for it; and we engaged the approach mode of the autopilot. We had briefed it during the decent as well just in case. I put it into the FMC and we continued to the DH. We could see the approach lights but not the runway; so we executed a missed. Realizing we were on a different misssed approach in direction of hold; we made sure we told ANC ATC when we contacted them that we were on the missed approach from the ILS; not the RNAV. Just before entering the hold; ANC ATC informed us of an altitude limit that they had that prevented them from giving us a late clearance for the ILS; but we thought KTN radios approval of the approach was good enough. The ANC controller said it was pretty much for information only; but providing this report may help other crews in the future. Cause; misunderstanding of who can clear us for approaches. We thought KTN radio could change us from the RNAV to the ILS. Suggestions; fly the approach you are last cleared for; do the missed approach if required; then try another approach.

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.

Attributes
ACN	876070
Time
Date	201002
Local Time Of Day	0001-0600
Place
Locale Reference	ZAN.ARTCC
State Reference	AK
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

Air carrier on approach to ktn and on ktn radio's frequency elects to change from RNAV to ILS approach ending in a missed approach procedure prompting questions regarding clearance procedure change authority.