A B727-200 crew descended below assigned altitude while on final to mke.

Attributes
ACN	514870
Time
Date	200106
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : mke.airport
State Reference	WI
Altitude	msl single value : 2800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : mke.tower
Operator	common carrier : air carrier
Make Model Name	B727-100
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer only : 19r
Flight Phase	descent : approach
Route In Use	approach : instrument non precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : flight engineer pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 68 flight time total : 2974 flight time type : 1425
ASRS Report	514870
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance Navigational Facility ATC Facility
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During approach to runway 19R at milwaukee, the tower cleared us to 2800 ft, tracking inbound on the runway 19R localizer to the OM (yanks). The tower advised that they would call the OM. We continued inbound and believing that the tower had called the OM we descended below 2800 ft. The tower corrected our mistake. We climbed immediately to 2800 ft, continued the approach and landed without incident. The inadvertent error occurred because of a misunderstanding and contributing factors were radio congestion in the form of broken and stepped-on xmissions plus the fact the OM was OTS or at least intermittent.

Original NASA ASRS Text

Title: A B727-200 CREW DSNDED BELOW ASSIGNED ALT WHILE ON FINAL TO MKE.

Narrative: DURING APCH TO RWY 19R AT MILWAUKEE, THE TWR CLRED US TO 2800 FT, TRACKING INBOUND ON THE RWY 19R LOC TO THE OM (YANKS). THE TWR ADVISED THAT THEY WOULD CALL THE OM. WE CONTINUED INBOUND AND BELIEVING THAT THE TWR HAD CALLED THE OM WE DSNDED BELOW 2800 FT. THE TWR CORRECTED OUR MISTAKE. WE CLBED IMMEDIATELY TO 2800 FT, CONTINUED THE APCH AND LANDED WITHOUT INCIDENT. THE INADVERTENT ERROR OCCURRED BECAUSE OF A MISUNDERSTANDING AND CONTRIBUTING FACTORS WERE RADIO CONGESTION IN THE FORM OF BROKEN AND STEPPED-ON XMISSIONS PLUS THE FACT THE OM WAS OTS OR AT LEAST INTERMITTENT.

Data retrieved from NASA's ASRS site as of July 2007 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.