Narrative:

The event involves closer than desirable proximity to terrain. Flight was a ferry flight ewr to ifp (bullhead city, az). Near the destination at night, unlimited visibility, clearance was given to 11000 ft with clearance for visual approach when visual contact was made with ifp. The original clearance was to eed VOR direct ifp, eed is south of ifp 25 mi. The published approach for ifp begins at eed VOR at 6000 ft and proceeds north to ifp. It is common, however, when VFR to intercept the approach course north of eed to expedite the approach. Our aircraft was approaching from the east at 11000 ft when bullhead city was in sight at 25 mi. We began descent to 6000 ft, first officer is flying. At some point, clearance was given direct to bullhead city. The first officer was intent on doing this. I, however, explained there was high terrain between us and the airport and the better approach was from the south in the vicinity of eed VOR and proceed north. This required 3 separate explanations to get him to modify our course to the south away from a direct course to bullhead. Finally, we were headed southwest to a point approximately 6 mi north of eed which in my experience in a daytime operation would have provided adequate terrain clearance at 6000 ft. The question was raised concerning our MSA. The approach chart was referenced and in what I perceived to be our quadrant the chart stated a MSA of 6100 ft, which added to my confidence in our altitude. We proceeded all the time keeping bullhead in sight. At some point, while proceeding southwest to intercept the approach course, I observed that the radar altitude was reading 2500 ft but at one point it abruptly decreased to 1000 ft whereupon I commanded a climb, to the best of my knowledge this was as close to the ground as we got. From this point the approach and landing proceeded normally. Looking back, there were several factors that led to descending to an altitude that did not provide sufficient terrain clearance, but one important one was a failure on my part to understand the MSA diagram at the top of the approach chart. At time of the incident, I placed our position in the lower right quadrant with an MSA of 6100 ft when in fact we were in the upper right quadrant with a higher MSA. This problem arose because I now believe the diagram is based on the approach fix eed 25 mi south, not center of the airport. Contributing factors: trying to use local knowledge at night and after being on duty for 14 hours, concern with fuel remaining after a 5 hour flight with a desire to expedite the approach to bullhead. ATC should probably not offer direct bullhead until passing eed, and the difficulty judging distance on a clear night.

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Original NASA ASRS Text

Title: FLC OF B727 ON NIGHT VISUAL APCH DSNDS BELOW MSA. CAPT NOTICES RADAR ALTIMETER AT 1000 FT AND CALLS FOR MISSED APCH.

Narrative: THE EVENT INVOLVES CLOSER THAN DESIRABLE PROX TO TERRAIN. FLT WAS A FERRY FLT EWR TO IFP (BULLHEAD CITY, AZ). NEAR THE DEST AT NIGHT, UNLIMITED VISIBILITY, CLRNC WAS GIVEN TO 11000 FT WITH CLRNC FOR VISUAL APCH WHEN VISUAL CONTACT WAS MADE WITH IFP. THE ORIGINAL CLRNC WAS TO EED VOR DIRECT IFP, EED IS S OF IFP 25 MI. THE PUBLISHED APCH FOR IFP BEGINS AT EED VOR AT 6000 FT AND PROCEEDS N TO IFP. IT IS COMMON, HOWEVER, WHEN VFR TO INTERCEPT THE APCH COURSE N OF EED TO EXPEDITE THE APCH. OUR ACFT WAS APCHING FROM THE E AT 11000 FT WHEN BULLHEAD CITY WAS IN SIGHT AT 25 MI. WE BEGAN DSCNT TO 6000 FT, FO IS FLYING. AT SOME POINT, CLRNC WAS GIVEN DIRECT TO BULLHEAD CITY. THE FO WAS INTENT ON DOING THIS. I, HOWEVER, EXPLAINED THERE WAS HIGH TERRAIN BTWN US AND THE ARPT AND THE BETTER APCH WAS FROM THE S IN THE VICINITY OF EED VOR AND PROCEED N. THIS REQUIRED 3 SEPARATE EXPLANATIONS TO GET HIM TO MODIFY OUR COURSE TO THE S AWAY FROM A DIRECT COURSE TO BULLHEAD. FINALLY, WE WERE HEADED SW TO A POINT APPROX 6 MI N OF EED WHICH IN MY EXPERIENCE IN A DAYTIME OP WOULD HAVE PROVIDED ADEQUATE TERRAIN CLRNC AT 6000 FT. THE QUESTION WAS RAISED CONCERNING OUR MSA. THE APCH CHART WAS REFED AND IN WHAT I PERCEIVED TO BE OUR QUADRANT THE CHART STATED A MSA OF 6100 FT, WHICH ADDED TO MY CONFIDENCE IN OUR ALT. WE PROCEEDED ALL THE TIME KEEPING BULLHEAD IN SIGHT. AT SOME POINT, WHILE PROCEEDING SW TO INTERCEPT THE APCH COURSE, I OBSERVED THAT THE RADAR ALT WAS READING 2500 FT BUT AT ONE POINT IT ABRUPTLY DECREASED TO 1000 FT WHEREUPON I COMMANDED A CLB, TO THE BEST OF MY KNOWLEDGE THIS WAS AS CLOSE TO THE GND AS WE GOT. FROM THIS POINT THE APCH AND LNDG PROCEEDED NORMALLY. LOOKING BACK, THERE WERE SEVERAL FACTORS THAT LED TO DSNDING TO AN ALT THAT DID NOT PROVIDE SUFFICIENT TERRAIN CLRNC, BUT ONE IMPORTANT ONE WAS A FAILURE ON MY PART TO UNDERSTAND THE MSA DIAGRAM AT THE TOP OF THE APCH CHART. AT TIME OF THE INCIDENT, I PLACED OUR POS IN THE LOWER R QUADRANT WITH AN MSA OF 6100 FT WHEN IN FACT WE WERE IN THE UPPER R QUADRANT WITH A HIGHER MSA. THIS PROB AROSE BECAUSE I NOW BELIEVE THE DIAGRAM IS BASED ON THE APCH FIX EED 25 MI S, NOT CTR OF THE ARPT. CONTRIBUTING FACTORS: TRYING TO USE LCL KNOWLEDGE AT NIGHT AND AFTER BEING ON DUTY FOR 14 HRS, CONCERN WITH FUEL REMAINING AFTER A 5 HR FLT WITH A DESIRE TO EXPEDITE THE APCH TO BULLHEAD. ATC SHOULD PROBABLY NOT OFFER DIRECT BULLHEAD UNTIL PASSING EED, AND THE DIFFICULTY JUDGING DISTANCE ON A CLR NIGHT.

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.