An air carrier crew reported an unstabilized approach and go around after a fluctuating glideslope c...

Attributes
ACN	920054
Time
Date	201011
Local Time Of Day	0601-1200
Place
Locale Reference	MSP.Airport
State Reference	MN
Environment
Flight Conditions	IMC
Light	Dawn
Aircraft 1
Make Model Name	Medium Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 121
Flight Phase	Final Approach Initial Approach
Flight Plan	IFR
Component
Aircraft Component	ILS/VOR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 250 Flight Crew Total 8000 Flight Crew Type 5800
Events
Anomaly	Inflight Event / Encounter Unstabilized Approach

Narrative:

First officer flying with autopilot engaged. We were established on 12L localizer; tracking inbound and cleared for ILS 12L. Glideslope was 'alive' and at 1 dot we configured gear down; flaps 30. Glideslope appeared to flucuate somewhat along with minor pitch changes. At or near FAF we elected to go-around as we were not fully configured or stablized. No other aircraft reported any problems with glideslope and we were vectored back around to a successful ILS 12L. Aircraft operated normally on the 2 additional flights after msp. Not sure if there was possible interference to either ground based or aircraft equipment. Neither ATC or other aircraft reported any problems with the glideslope. The best action is to always monitor the aircraft and system indications closely and take the appropriate action when not stablized per operations manual.

Original NASA ASRS Text

Title: An Air Carrier crew reported an unstabilized approach and go around after a fluctuating glideslope caused them to be high on final to MSP Runway 12L. The subsequent approach was normal and stable.

Narrative: First Officer flying with autopilot engaged. We were established on 12L LOC; tracking inbound and cleared for ILS 12L. Glideslope was 'alive' and at 1 dot we configured gear down; flaps 30. Glideslope appeared to flucuate somewhat along with minor pitch changes. At or near FAF we elected to go-around as we were not fully configured or stablized. No other aircraft reported any problems with glideslope and we were vectored back around to a successful ILS 12L. Aircraft operated normally on the 2 additional flights after MSP. Not sure if there was possible interference to either ground based or aircraft equipment. Neither ATC or other aircraft reported any problems with the glideslope. The best action is to always monitor the aircraft and system indications closely and take the appropriate action when not stablized per Operations Manual.

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.

An air carrier crew reported an unstabilized approach and go around after a fluctuating glideslope caused them to be high on final to msp runway 12L. The subsequent approach was normal and stable.