K9S5 · Three Forks Airport

THREE FORKS, MONTANA · SMALL AIRPORT

4,089

Elevation ft

Runway

5,100

Longest ft · 02/20

45.88N

111.57W

Three Forks Airport serves Three Forks, Montana at 4,089 ft elevation with its longest runway, 02/20, at 5,100 by 60 ft. The figures below are computed from FAA NASR runway data (via OurAirports) and the same rules of thumb JetDesk uses on the airport page in the app; the POH and current NOTAMs are the authority.

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01Runways

Runway	Length × width	Surface	Lighting
02/20	5,100 × 60 ft	asphalt	lit

02Density altitude and turboprop runway margins

Standard temperature at 4,089 ft is about 7°C. Every 1,000 ft of density altitude adds roughly 8 percent to a turboprop's takeoff distance and 5 percent to its landing distance. The table uses Piper Meridian book numbers (2,438 ft takeoff and 2,110 ft landing over a 50 ft obstacle at sea level, ISA, max weight) as a reference airplane; heavier turboprops and light jets scale the same way from their own POH figures.

Conditions	Density altitude	Takeoff est.	Landing est.	Landing × 1.5
Standard day (ISA, 7°C)	4,089 ft	3,236 ft	2,541 ft	3,812 ft
Warm day (ISA +10)	5,289 ft	3,470 ft	2,668 ft	4,002 ft
Hot day (ISA +20)	6,489 ft	3,704 ft	2,795 ft	4,192 ft
35°C afternoon	7,470 ft	3,895 ft	2,898 ft	4,347 ft

Planning aid only. Even on a 35°C afternoon the longest runway (02/20, 5,100 ft) covers a Meridian-class turboprop's landing distance with a 50 percent margin (4,347 ft needed). The percentages are a generic rule of thumb applied to one reference airplane, not certified performance data for any specific aircraft, and the runway size categories describe the runway, not your airplane's suitability. Verify with the approved flight manual before every flight.

03Nearby fields with 5,000 ft or more

Useful as alternates, as fuel stops when the price at K9S5 is high, or as the longer runway on a hot afternoon.

Airport	Distance	Longest runway
KBZN Bozeman Yellowstone International Airport	18 nm E	8,994 ft
KEKS Ennis Big Sky Airport	37 nm S	7,600 ft
KRVF Ruby Valley Field	37 nm SW	6,000 ft
KBTM Bert Mooney Airport	39 nm W	9,000 ft
K7S6 White Sulphur Springs Airport	46 nm NE	6,100 ft
KHLN Helena Regional Airport	47 nm N	9,000 ft

04Jet A prices and FBOs at K9S5

No public API publishes FBO fuel prices, so JetDesk does not guess. Pilots and crews log the price they actually paid at K9S5, the app flags a price stale after two weeks, and the route finder ranks every field within a corridor of your route by net savings after the cost of the extra cycle. Log a price at K9S5 or read what a fuel stop actually saves.

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