Reporter flight began descent on approach prior to reaching the initial approach fix.

Attributes
ACN	112184
Time
Date	198905
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mia
State Reference	FL
Altitude	msl bound lower : 2750 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : mia
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument
Experience	flight time last 90 days : 72 flight time total : 8200 flight time type : 4456
ASRS Report	112184
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : published procedure non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Captain copied ATIS while I flew and monitored ATC. He wrote down that ILS 9R, 9L and 12 in use at mia. Approach cleared us for the ILS 9R to cross the IAF (which is an intersection off of mia VOR) at 3000'. (This intersection is also the G/south intercept). At the G/south intercept, I started down the G/south with the runway in sight (captain didn't bother to have cross radio defining intersection set-up) and at 2750' MSL the controller told us to check our altitude. I immediately leveled off. He said we were still 1 mi from the IAF and at this time we were told the 9R G/south was OTS. The captain claims this information was not on the ATIS, which I was never able to confirm or deny. The real problem here is that many ATC controllers will clear an aircraft for an ILS approach (when the G/south is OTS), instead of 'cleared for the ILS 9R G/south OTS.'

Original NASA ASRS Text

Title: REPORTER FLT BEGAN DESCENT ON APCH PRIOR TO REACHING THE INITIAL APCH FIX.

Narrative: CAPT COPIED ATIS WHILE I FLEW AND MONITORED ATC. HE WROTE DOWN THAT ILS 9R, 9L AND 12 IN USE AT MIA. APCH CLRED US FOR THE ILS 9R TO CROSS THE IAF (WHICH IS AN INTXN OFF OF MIA VOR) AT 3000'. (THIS INTXN IS ALSO THE G/S INTERCEPT). AT THE G/S INTERCEPT, I STARTED DOWN THE G/S WITH THE RWY IN SIGHT (CAPT DIDN'T BOTHER TO HAVE CROSS RADIO DEFINING INTXN SET-UP) AND AT 2750' MSL THE CTLR TOLD US TO CHK OUR ALT. I IMMEDIATELY LEVELED OFF. HE SAID WE WERE STILL 1 MI FROM THE IAF AND AT THIS TIME WE WERE TOLD THE 9R G/S WAS OTS. THE CAPT CLAIMS THIS INFO WAS NOT ON THE ATIS, WHICH I WAS NEVER ABLE TO CONFIRM OR DENY. THE REAL PROB HERE IS THAT MANY ATC CTLRS WILL CLR AN ACFT FOR AN ILS APCH (WHEN THE G/S IS OTS), INSTEAD OF 'CLRED FOR THE ILS 9R G/S OTS.'

Data retrieved from NASA's ASRS site as of August 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.