Research C130 low level calibration flight over a lake raises security concerns by dam personnel.

Attributes
ACN	594534
Time
Date	200309
Day	Fri
Local Time Of Day	1201 To 1800
Place
State Reference	US
Altitude	agl single value : 60
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	Other
Make Model Name	Hercules (C-130)
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Plan	VFR
Person 1
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : cfi
Experience	flight time last 90 days : 10 flight time total : 2100 flight time type : 350
ASRS Report	594534
Person 2
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 30 flight time total : 5600 flight time type : 1550
ASRS Report	594538
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa other flight crewb other other : person 3
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Problem Areas	Environmental Factor Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

After completing atmosphere research, approximately 3 NM north of the lake, we descended to 1000 ft AGL to set up an onboard scientific instrument calibration run over the water. Approximately 1/4 mi north of the lake, we noticed that the terrain dropped sharply at the lake's edge (back). We descended over the lake's north bank to maintain 1000 ft AGL. As we flew towards the south bank of the lake, we realized the terrain rose slightly which placed the aircraft at 600 ft AGL as we passed over the southern shoreline. We began a climbing right turn back to the northwest to set up one final calibration run over the same track using the same altitude profile. Although we briefly were at 600 ft AGL, the C130 is a large aircraft and may appear to be lower than it actually is when viewed from the ground. In retrospect, a call to the bureau of reclamation in charge of the dam, before our flight, would have precluded any concern of possible damage to the dam, especially in light of sep/11 events. We will also conduct future calibration flts at 1500 ft AGL, allowing more buffer for terrain features. Supplemental information from acn 594538: we had a complaint from bureau of reclamation in charge of the dam. They feared we were going to cause damage to the dam.

Original NASA ASRS Text

Title: RESEARCH C130 LOW LEVEL CALIBRATION FLT OVER A LAKE RAISES SECURITY CONCERNS BY DAM PERSONNEL.

Narrative: AFTER COMPLETING ATMOSPHERE RESEARCH, APPROX 3 NM N OF THE LAKE, WE DSNDED TO 1000 FT AGL TO SET UP AN ONBOARD SCIENTIFIC INST CALIBRATION RUN OVER THE WATER. APPROX 1/4 MI N OF THE LAKE, WE NOTICED THAT THE TERRAIN DROPPED SHARPLY AT THE LAKE'S EDGE (BACK). WE DSNDED OVER THE LAKE'S N BANK TO MAINTAIN 1000 FT AGL. AS WE FLEW TOWARDS THE S BANK OF THE LAKE, WE REALIZED THE TERRAIN ROSE SLIGHTLY WHICH PLACED THE ACFT AT 600 FT AGL AS WE PASSED OVER THE SOUTHERN SHORELINE. WE BEGAN A CLBING R TURN BACK TO THE NW TO SET UP ONE FINAL CALIBRATION RUN OVER THE SAME TRACK USING THE SAME ALT PROFILE. ALTHOUGH WE BRIEFLY WERE AT 600 FT AGL, THE C130 IS A LARGE ACFT AND MAY APPEAR TO BE LOWER THAN IT ACTUALLY IS WHEN VIEWED FROM THE GND. IN RETROSPECT, A CALL TO THE BUREAU OF RECLAMATION IN CHARGE OF THE DAM, BEFORE OUR FLT, WOULD HAVE PRECLUDED ANY CONCERN OF POSSIBLE DAMAGE TO THE DAM, ESPECIALLY IN LIGHT OF SEP/11 EVENTS. WE WILL ALSO CONDUCT FUTURE CALIBRATION FLTS AT 1500 FT AGL, ALLOWING MORE BUFFER FOR TERRAIN FEATURES. SUPPLEMENTAL INFO FROM ACN 594538: WE HAD A COMPLAINT FROM BUREAU OF RECLAMATION IN CHARGE OF THE DAM. THEY FEARED WE WERE GOING TO CAUSE DAMAGE TO THE DAM.

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.