Pilot of a small aircraft encounted a downdraft while flying by a national monument site and descend...

Narrative:

No fars were broken and at no time did I feel that I; (the only occupant of the aircraft); anything or structure was in danger. I was on a long; cross country in a slow plane.... At cut I picked up an FAA flyer about flying near mt rushmore- my intent was to fly by mt. Rushmore and be on my way east. Upon departure from cut I noticed a mountainside that had been exposed and knowing that the 'crazy horse' stone carving was near by; I diverted to investigate. I slowed the plane to 70 mph and set in 20 degrees of flaps and reduced power to maintain a 300 FPM descent from 7;500 MSL. A quick look at my chart (on the ipad) showed a monument marker ahead but no restricted airspace around it. I decided it was best to keep a wide berth from the monument and to stay well above it. I decided on 2;000 ft horizontally and to stay above the high ground (7;242 ft) to the east. As I approached the monument from the southeast on a northerly heading; I encountered a sink that required I apply power to maintain level flight and; in addition; I turned toward the monument in order to stay away from the rising terrain to the east in case I was unable to out climb the sinking air. The sinking air caused me to break my personal preset standard clearance of the monument of 2;000 ft horizontally and to stay above the high ground to the east. My best estimate is that I got between 1;500 and 2;000 ft horizontally of the monument while maintaining 7;200 MSL- all legal; but not what I had planned. I soon cleared the ridge to the north with ample room to spare and was on my way east skipping my earlier plan to fly over mt rushmore. I am writing this as a way to remind myself to do a better job of planning and to not be suckered in by chance encounters with interesting objects on the ground calling me to 'have a look'; especially in a plane that does low and slow well because low and slow can turn into spin and die. My excitement to see the crazy horse carving from the air; a nimble slow flying and high performance aircraft and not following my plan to fly directly from cut to the mt. Rushmore monument; all resulted in putting me in a less than desirable position that could have been avoided.

Original NASA ASRS Text

Title: Pilot of a small aircraft encounted a downdraft while flying by a National Monument site and descended lower than planned; but did not violate FAR restrictions.

Narrative: No FARs were broken and at no time did I feel that I; (the only occupant of the aircraft); anything or structure was in danger. I was on a long; cross country in a slow plane.... At CUT I picked up an FAA flyer about flying near Mt Rushmore- my intent was to fly by Mt. Rushmore and be on my way east. Upon departure from CUT I noticed a mountainside that had been exposed and knowing that the 'Crazy Horse' stone carving was near by; I diverted to investigate. I slowed the plane to 70 MPH and set in 20 degrees of flaps and reduced power to maintain a 300 FPM descent from 7;500 MSL. A quick look at my chart (on the iPad) showed a monument marker ahead but no restricted airspace around it. I decided it was best to keep a wide berth from the monument and to stay well above it. I decided on 2;000 FT horizontally and to stay above the high ground (7;242 FT) to the east. As I approached the monument from the southeast on a northerly heading; I encountered a sink that required I apply power to maintain level flight and; in addition; I turned toward the monument in order to stay away from the rising terrain to the east in case I was unable to out climb the sinking air. The sinking air caused me to break my personal preset standard clearance of the monument of 2;000 FT horizontally and to stay above the high ground to the east. My best estimate is that I got between 1;500 and 2;000 FT horizontally of the monument while maintaining 7;200 MSL- all legal; but not what I had planned. I soon cleared the ridge to the north with ample room to spare and was on my way east skipping my earlier plan to fly over Mt Rushmore. I am writing this as a way to remind myself to do a better job of planning and to not be suckered in by chance encounters with interesting objects on the ground calling me to 'have a look'; especially in a plane that does low and slow well because low and slow can turn into spin and die. My excitement to see the Crazy Horse carving from the air; a nimble slow flying and high performance aircraft and not following my plan to fly directly from CUT to the Mt. Rushmore Monument; all resulted in putting me in a less than desirable position that could have been avoided.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1020959
Time
Date	201206
Local Time Of Day	1201-1800
Place
Locale Reference	CUT.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A-1 Husky
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	None
Flight Plan	None
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 45 Flight Crew Total 2400 Flight Crew Type 20
Events
Anomaly	Deviation - Procedural Other / Unknown Inflight Event / Encounter Weather / Turbulence
Miss Distance	Horizontal 1000 Vertical 1000

Pilot of a small aircraft encounted a downdraft while flying by a national monument site and descended lower than planned; but did not violate far restrictions.