S56 controller described an apparent altitude deviation by an inbound aircraft during simultaneous a...

Attributes
ACN	940750
Time
Date	201103
Local Time Of Day	1201-1800
Place
Locale Reference	SLC.Airport
State Reference	UT
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural FAR Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

While working final monitor; the jordan controller called me and said 'watch the B737'. The B737 had just checked on tower frequency a few seconds before for monitor. He should have been at 11;000 for the approach. He was indicating 106 and descending. I asked him to verify that he was at 110. He said that he was descending to 100 and was cleared for the approach. I reminded him that the altitude at plage was 110. He descended to 102. I did not climb him back up because there was no one next to him and mvas were not a factor either. No loss of any forms of separation/mvas. We do see this once in a while on the runway 34R ILS approach when we are in simuls. I did not review the tape to see if this was a hearback/readback error on the part of the jordan controller.

Original NASA ASRS Text

Title: S56 Controller described an apparent altitude deviation by an inbound aircraft during simultaneous approach procedures; noting the criticality of altitude compliance during this type of operation.

Narrative: While working Final Monitor; the Jordan Controller called me and said 'watch the B737'. The B737 had just checked on Tower frequency a few seconds before for monitor. He should have been at 11;000 for the approach. He was indicating 106 and descending. I asked him to verify that he was at 110. He said that he was descending to 100 and was cleared for the approach. I reminded him that the altitude at PLAGE was 110. He descended to 102. I did not climb him back up because there was no one next to him and MVAs were not a factor either. No loss of any forms of separation/MVAs. We do see this once in a while on the Runway 34R ILS approach when we are in SIMULS. I did not review the tape to see if this was a hearback/readback error on the part of the Jordan Controller.

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.

S56 controller described an apparent altitude deviation by an inbound aircraft during simultaneous approach procedures; noting the criticality of altitude compliance during this type of operation.