Tower advises charter flight on localizer approach to check altitude.

Attributes
ACN	264880
Time
Date	199402
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ptk
State Reference	MI
Altitude	agl bound lower : 540 agl bound upper : 540
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : ptk
Operator	other
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 135
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument
Experience	flight time last 90 days : 100 flight time total : 8000 flight time type : 25
ASRS Report	264880
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : published procedure other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	other

Narrative:

On localizer only ILS approach, we did a fairly rapid descent to MDA. (We had just previously done the approach and broke out too close to the airport to descend and land on the first 1/3 of the runway, so we did a missed approach.) we leveled off at MDA with the ground in sight and then the runway. The tower controller told us to check our altitude immediately, that we were low. Probably the ATC radar computer projected our flight path, based on the descent rate to MDA, and sounded an alarm. I told the tower we had the ground and runway in sight and were descending visually. We landed without incident.

Original NASA ASRS Text

Title: TWR ADVISES CHARTER FLT ON LOC APCH TO CHK ALT.

Narrative: ON LOC ONLY ILS APCH, WE DID A FAIRLY RAPID DSCNT TO MDA. (WE HAD JUST PREVIOUSLY DONE THE APCH AND BROKE OUT TOO CLOSE TO THE ARPT TO DSND AND LAND ON THE FIRST 1/3 OF THE RWY, SO WE DID A MISSED APCH.) WE LEVELED OFF AT MDA WITH THE GND IN SIGHT AND THEN THE RWY. THE TWR CTLR TOLD US TO CHK OUR ALT IMMEDIATELY, THAT WE WERE LOW. PROBABLY THE ATC RADAR COMPUTER PROJECTED OUR FLT PATH, BASED ON THE DSCNT RATE TO MDA, AND SOUNDED AN ALARM. I TOLD THE TWR WE HAD THE GND AND RWY IN SIGHT AND WERE DSNDING VISUALLY. WE LANDED WITHOUT INCIDENT.

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.