An atx AS50 pilot reports crossing a ridge below 500 ft AGL during a sight seeing tour.

Attributes
ACN	391867
Time
Date	199801
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ogg
State Reference	HI
Altitude	agl bound lower : 200 agl bound upper : 500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ogg
Operator	common carrier : air taxi
Make Model Name	AS 350 Astar/Ecureuil
Operating Under FAR Part	Part 135
Flight Phase	climbout : intermediate altitude cruise other descent : intermediate altitude
Route In Use	enroute airway : ogg
Flight Plan	VFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 280 flight time total : 5700 flight time type : 2500
ASRS Report	391867
Events
Anomaly	non adherence : published procedure non adherence : far other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Flying a part 135 air tour (unscheduled) under provisions of sfar-71. Flying in west maui mountains, aircraft crossed a ridge line less than outlined in sfar-71. Altitude above ground should have been 500 ft AGL and crossing was substantially less. Crossing altitude was unintentionally closer than expected. As PIC I unintentionally underestimated climb rate for ridge crossing. I was and am very familiar with ridge's altitude and aircraft performance. My unintentional crossing was a mistake. Predominant winds from the north (trade winds) provide excellent lift and increase in aircraft performance. On jan/xx/98, the winds were from the south. I was aware of the prevailing WX and winds, but failed to recognize the loss of lift on southern ridges until too close to correct. Aircraft safely crossed ridge without excessive control inputs. Crossing altitude appeared safe, but not required 500 ft AGL. Crossing altitude was approximately 200 ft maybe less. At time my attention was on safe operation of aircraft not on specific crossing ht. Continued flight without further incident.

Original NASA ASRS Text

Title: AN ATX AS50 PLT RPTS XING A RIDGE BELOW 500 FT AGL DURING A SIGHT SEEING TOUR.

Narrative: FLYING A PART 135 AIR TOUR (UNSCHEDULED) UNDER PROVISIONS OF SFAR-71. FLYING IN W MAUI MOUNTAINS, ACFT CROSSED A RIDGE LINE LESS THAN OUTLINED IN SFAR-71. ALT ABOVE GND SHOULD HAVE BEEN 500 FT AGL AND XING WAS SUBSTANTIALLY LESS. XING ALT WAS UNINTENTIONALLY CLOSER THAN EXPECTED. AS PIC I UNINTENTIONALLY UNDERESTIMATED CLB RATE FOR RIDGE XING. I WAS AND AM VERY FAMILIAR WITH RIDGE'S ALT AND ACFT PERFORMANCE. MY UNINTENTIONAL XING WAS A MISTAKE. PREDOMINANT WINDS FROM THE N (TRADE WINDS) PROVIDE EXCELLENT LIFT AND INCREASE IN ACFT PERFORMANCE. ON JAN/XX/98, THE WINDS WERE FROM THE S. I WAS AWARE OF THE PREVAILING WX AND WINDS, BUT FAILED TO RECOGNIZE THE LOSS OF LIFT ON SOUTHERN RIDGES UNTIL TOO CLOSE TO CORRECT. ACFT SAFELY CROSSED RIDGE WITHOUT EXCESSIVE CTL INPUTS. XING ALT APPEARED SAFE, BUT NOT REQUIRED 500 FT AGL. XING ALT WAS APPROX 200 FT MAYBE LESS. AT TIME MY ATTN WAS ON SAFE OP OF ACFT NOT ON SPECIFIC XING HT. CONTINUED FLT WITHOUT FURTHER 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.