MSAW activated by air carrier medium large transport making a VOR approach to dtw.

Attributes
ACN	158982
Time
Date	199010
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dtw
State Reference	MI
Altitude	msl bound lower : 1100 msl bound upper : 2500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tower : dtw tower : vny
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach descent other landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12800 flight time type : 7600
ASRS Report	158982
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

We were on the approach to runway 21R on a VOR/DME approach. After passing the final approach fix inbound, we descended to 1100' as depicted on the chart. This descent was done quickly (1000 FPM) as per company policy. After about 10 seconds level at the MDA of 1100', the tower controller (in a very excited fashion) warned us: 'low altitude warning--check altitude immediately.' our first impression was that we had messed up. We checked the approach plate, altimeter setting, DME, VOR frequency--all was proper. After landing, I called the tower to find out what the basis of a low altitude warning is. The controller replied that it is based on the ILS G/south plane. We were on a VOR approach. It is perfectly normal to get down to your MDA on a non precision approach quickly, and at the MDA you may be lower than the G/south at that distance from the runway. Although I agree with the intention of the low altitude warning, I disagree about its bases when applied to a non precision approach. The last thing you need when at the MDA looking for the runway is an excited controller implying that you're about to hit the ground (when the approach is flown as published). Low altitude warnings should be approach specific: ILS approach--lower than the G/south; non precision approach--lower than the MDA.

Original NASA ASRS Text

Title: MSAW ACTIVATED BY ACR MLG MAKING A VOR APCH TO DTW.

Narrative: WE WERE ON THE APCH TO RWY 21R ON A VOR/DME APCH. AFTER PASSING THE FINAL APCH FIX INBND, WE DSNDED TO 1100' AS DEPICTED ON THE CHART. THIS DSNT WAS DONE QUICKLY (1000 FPM) AS PER COMPANY POLICY. AFTER ABOUT 10 SECS LEVEL AT THE MDA OF 1100', THE TWR CTLR (IN A VERY EXCITED FASHION) WARNED US: 'LOW ALT WARNING--CHK ALT IMMEDIATELY.' OUR FIRST IMPRESSION WAS THAT WE HAD MESSED UP. WE CHKED THE APCH PLATE, ALTIMETER SETTING, DME, VOR FREQ--ALL WAS PROPER. AFTER LNDG, I CALLED THE TWR TO FIND OUT WHAT THE BASIS OF A LOW ALT WARNING IS. THE CTLR REPLIED THAT IT IS BASED ON THE ILS G/S PLANE. WE WERE ON A VOR APCH. IT IS PERFECTLY NORMAL TO GET DOWN TO YOUR MDA ON A NON PRECISION APCH QUICKLY, AND AT THE MDA YOU MAY BE LOWER THAN THE G/S AT THAT DISTANCE FROM THE RWY. ALTHOUGH I AGREE WITH THE INTENTION OF THE LOW ALT WARNING, I DISAGREE ABOUT ITS BASES WHEN APPLIED TO A NON PRECISION APCH. THE LAST THING YOU NEED WHEN AT THE MDA LOOKING FOR THE RWY IS AN EXCITED CTLR IMPLYING THAT YOU'RE ABOUT TO HIT THE GND (WHEN THE APCH IS FLOWN AS PUBLISHED). LOW ALT WARNINGS SHOULD BE APCH SPECIFIC: ILS APCH--LOWER THAN THE G/S; NON PRECISION APCH--LOWER THAN THE MDA.

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.