Narrative:

Flight sep/xx/96 ord-boi was east of the field at 7000 ft. Under radar control being vectored for a visual approach to runway 28L then runway 28R. Another flight was being put on the approach to runway 28L (visual). We were then assigned runway 28R. The field was VFR and clear. We were over a 'black hole' visual situation due to little or no moonlight and the lightless high terrain below us. Some scattered clouds were in our area. The approach controller did virtually no sequencing by speed or vectoring to keep the 2 aircraft in an ordered arrival sequence. Namely, the 2 runways are less than 500 ft apart in terms of ctrlines. Someone had to follow another. Both aircraft were closing to the same point to more or less sequence themselves visually. The aircraft closing on runway 28L was in our 8-9 O'clock relative position and lower. He was difficult to see at times. The controller first asked us if we had the field in sight at approximately 15-16 NM out. We wanted to be more certain and get closer before saying yes. At approximately 11 NM we acknowledged 'field in sight' and were cleared for the visual approach to runway 28R. Our flight was at 7000 ft MSL and 180 KTS, flaps 10 degrees, as we had been slowing to try to sequence behind the runway 28L traffic as it seemed faster or at least would be first to the runway. Cockpit workload was high and it was difficult to always see the runway 28L traffic. We seemed to be at a reasonable angle and distance to begin descent toward runway 28R. At approximately 6500 ft an aural warning of 'terrain, terrain' was heard. We immediately began our prescribed pullup maneuver. PF (captain) made the radio call to approach to advise of the maneuver and request vectors for runway 28L. We were given a right 360 degree turn to about 150 degree heading for runway 28L visual. A normal descent, approach, and landing resulted on runway 28L. My conclusions are: that boi cries out for an area chart. Visuals from the east need more control and care on the approach controller's part. Descent based on radials and altitudes would help. The aural warning of 'terrain, terrain' happened only because we were not in the landing confign (ie, 180 KTS, flaps 10 degrees). IFR aircraft at 7000 ft MSL are well below the MSA already (MSA 9400 ft MSL) and need more information. Better aircraft sequencing by the controller would have made this a non event. Black hole conditions make terrain avoidance at night virtually impossible.

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Original NASA ASRS Text

Title: ACR RPTR EXPERIENCED A GPWS ALARM DURING A VISUAL APCH AT NIGHT TO RWY 28R AT BOI. RPTR CONTENDS THAT BOI SHOULD HAVE AN AREA CHART FOR PLT REF DUE TO HIGH TERRAIN IN THE BOI AREA.

Narrative: FLT SEP/XX/96 ORD-BOI WAS E OF THE FIELD AT 7000 FT. UNDER RADAR CTL BEING VECTORED FOR A VISUAL APCH TO RWY 28L THEN RWY 28R. ANOTHER FLT WAS BEING PUT ON THE APCH TO RWY 28L (VISUAL). WE WERE THEN ASSIGNED RWY 28R. THE FIELD WAS VFR AND CLR. WE WERE OVER A 'BLACK HOLE' VISUAL SIT DUE TO LITTLE OR NO MOONLIGHT AND THE LIGHTLESS HIGH TERRAIN BELOW US. SOME SCATTERED CLOUDS WERE IN OUR AREA. THE APCH CTLR DID VIRTUALLY NO SEQUENCING BY SPD OR VECTORING TO KEEP THE 2 ACFT IN AN ORDERED ARR SEQUENCE. NAMELY, THE 2 RWYS ARE LESS THAN 500 FT APART IN TERMS OF CTRLINES. SOMEONE HAD TO FOLLOW ANOTHER. BOTH ACFT WERE CLOSING TO THE SAME POINT TO MORE OR LESS SEQUENCE THEMSELVES VISUALLY. THE ACFT CLOSING ON RWY 28L WAS IN OUR 8-9 O'CLOCK RELATIVE POS AND LOWER. HE WAS DIFFICULT TO SEE AT TIMES. THE CTLR FIRST ASKED US IF WE HAD THE FIELD IN SIGHT AT APPROX 15-16 NM OUT. WE WANTED TO BE MORE CERTAIN AND GET CLOSER BEFORE SAYING YES. AT APPROX 11 NM WE ACKNOWLEDGED 'FIELD IN SIGHT' AND WERE CLRED FOR THE VISUAL APCH TO RWY 28R. OUR FLT WAS AT 7000 FT MSL AND 180 KTS, FLAPS 10 DEGS, AS WE HAD BEEN SLOWING TO TRY TO SEQUENCE BEHIND THE RWY 28L TFC AS IT SEEMED FASTER OR AT LEAST WOULD BE FIRST TO THE RWY. COCKPIT WORKLOAD WAS HIGH AND IT WAS DIFFICULT TO ALWAYS SEE THE RWY 28L TFC. WE SEEMED TO BE AT A REASONABLE ANGLE AND DISTANCE TO BEGIN DSCNT TOWARD RWY 28R. AT APPROX 6500 FT AN AURAL WARNING OF 'TERRAIN, TERRAIN' WAS HEARD. WE IMMEDIATELY BEGAN OUR PRESCRIBED PULLUP MANEUVER. PF (CAPT) MADE THE RADIO CALL TO APCH TO ADVISE OF THE MANEUVER AND REQUEST VECTORS FOR RWY 28L. WE WERE GIVEN A R 360 DEG TURN TO ABOUT 150 DEG HDG FOR RWY 28L VISUAL. A NORMAL DSCNT, APCH, AND LNDG RESULTED ON RWY 28L. MY CONCLUSIONS ARE: THAT BOI CRIES OUT FOR AN AREA CHART. VISUALS FROM THE E NEED MORE CTL AND CARE ON THE APCH CTLR'S PART. DSCNT BASED ON RADIALS AND ALTS WOULD HELP. THE AURAL WARNING OF 'TERRAIN, TERRAIN' HAPPENED ONLY BECAUSE WE WERE NOT IN THE LNDG CONFIGN (IE, 180 KTS, FLAPS 10 DEGS). IFR ACFT AT 7000 FT MSL ARE WELL BELOW THE MSA ALREADY (MSA 9400 FT MSL) AND NEED MORE INFO. BETTER ACFT SEQUENCING BY THE CTLR WOULD HAVE MADE THIS A NON EVENT. BLACK HOLE CONDITIONS MAKE TERRAIN AVOIDANCE AT NIGHT VIRTUALLY IMPOSSIBLE.

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.