Narrative:

On approach into enw; approach control handed us to tower for the VOR/GPS runway 24R. We contacted tower and within 10 NM as per the approach; descended below 2500 ft down to the final MDA of 1360 ft. Around 7 NM from the VOR; tower advised us of a terrain alert! We looked perplexed since our altitude within 10 NM was at 1360 ft for the MDA within the approach parameter and were starting to see the water; the coast; and the airport. We told tower about our visual situation and tower advised us of a tower in the vicinity that we acknowledged as having it in sight. We believe that we flew the approach as published and having visual; no safety parameters were compromised.callback conversation with reporter revealed the following information: reporter advised that they were wbound; east of enw over lake michigan; when mke approach cleared them for a straight in GPS runway 24R approach. The flight crew discussed the lack of a published descent point and decided the published 10 mile limit for the procedure turn constituted a valid point at which a descent below the procedure turn altitude could be initiated. Reporter stated the local controller seemed concerned about their altitude and inquired at least twice as to whether they were having a problem. Reporter suggested that if there was concern regarding terrain on such an approach it should be required that approach include a 'maintain (an appropriate) altitude until (a specific) DME distance' restriction to the approach clearance. Reporter maintains that the flight crew's actions were in compliance with both their clearance and the parameters of the approach plate. Reporter commented that another flight crew advised they had experienced the same situation on an earlier flight.

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Original NASA ASRS Text

Title: LR45 FLT CREW IS CLRED FOR STRAIGHT IN GPS RWY 24R APCH TO ENW. DSNDED TO MDA WHEN WITHIN 10 NM BECAUSE NO STEP DOWN FIX WAS PUBLISHED. LOW ALT ALERT IS GENERATED IN THE TWR.

Narrative: ON APCH INTO ENW; APCH CTL HANDED US TO TWR FOR THE VOR/GPS RWY 24R. WE CONTACTED TWR AND WITHIN 10 NM AS PER THE APCH; DSNDED BELOW 2500 FT DOWN TO THE FINAL MDA OF 1360 FT. AROUND 7 NM FROM THE VOR; TWR ADVISED US OF A TERRAIN ALERT! WE LOOKED PERPLEXED SINCE OUR ALT WITHIN 10 NM WAS AT 1360 FT FOR THE MDA WITHIN THE APCH PARAMETER AND WERE STARTING TO SEE THE WATER; THE COAST; AND THE ARPT. WE TOLD TWR ABOUT OUR VISUAL SITUATION AND TWR ADVISED US OF A TWR IN THE VICINITY THAT WE ACKNOWLEDGED AS HAVING IT IN SIGHT. WE BELIEVE THAT WE FLEW THE APCH AS PUBLISHED AND HAVING VISUAL; NO SAFETY PARAMETERS WERE COMPROMISED.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT THEY WERE WBOUND; E OF ENW OVER LAKE MICHIGAN; WHEN MKE APCH CLRED THEM FOR A STRAIGHT IN GPS RWY 24R APCH. THE FLT CREW DISCUSSED THE LACK OF A PUBLISHED DSCNT POINT AND DECIDED THE PUBLISHED 10 MILE LIMIT FOR THE PROC TURN CONSTITUTED A VALID POINT AT WHICH A DSCNT BELOW THE PROC TURN ALT COULD BE INITIATED. RPTR STATED THE LOCAL CTLR SEEMED CONCERNED ABOUT THEIR ALT AND INQUIRED AT LEAST TWICE AS TO WHETHER THEY WERE HAVING A PROB. RPTR SUGGESTED THAT IF THERE WAS CONCERN REGARDING TERRAIN ON SUCH AN APCH IT SHOULD BE REQUIRED THAT APCH INCLUDE A 'MAINTAIN (AN APPROPRIATE) ALT UNTIL (A SPECIFIC) DME DISTANCE' RESTRICTION TO THE APCH CLRNC. RPTR MAINTAINS THAT THE FLT CREW'S ACTIONS WERE IN COMPLIANCE WITH BOTH THEIR CLRNC AND THE PARAMETERS OF THE APCH PLATE. RPTR COMMENTED THAT ANOTHER FLT CREW ADVISED THEY HAD EXPERIENCED THE SAME SITUATION ON AN EARLIER FLT.

Data retrieved from NASA's ASRS site as of January 2009 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.