KRPX · Roundup Airport

ROUNDUP, MONTANA · SMALL AIRPORT

3,500

Elevation ft

Runways

5,098

Longest ft · 07/25

46.48N

108.54W

Roundup Airport serves Roundup, Montana at 3,500 ft elevation with its longest runway, 07/25, at 5,098 by 75 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.

Open KRPX in JetDesk: live METAR, TAF, winds and runway verdict →

01Runways

Runway	Length × width	Surface	Lighting
07/25	5,098 × 75 ft	asphalt	lit
16/34	2,460 × 100 ft	turf	unlit

02Density altitude and turboprop runway margins

Standard temperature at 3,500 ft is about 8°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, 8°C)	3,500 ft	3,121 ft	2,479 ft	3,719 ft
Warm day (ISA +10)	4,700 ft	3,355 ft	2,606 ft	3,909 ft
Hot day (ISA +20)	5,900 ft	3,589 ft	2,732 ft	4,099 ft
35°C afternoon	6,740 ft	3,753 ft	2,821 ft	4,232 ft

Planning aid only. Even on a 35°C afternoon the longest runway (07/25, 5,098 ft) covers a Meridian-class turboprop's landing distance with a 50 percent margin (4,232 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 KRPX is high, or as the longer runway on a hot afternoon.

Airport	Distance	Longest runway
KBIL Billings Logan International Airport	40 nm S	10,518 ft
K6S8 Laurel Municipal Airport	47 nm S	5,199 ft
KLWT Lewistown Municipal Airport	51 nm NW	6,100 ft
K6S0 Big Timber Airport	72 nm SW	5,285 ft
KM46 Colstrip Airport	85 nm SE	5,100 ft

04Jet A prices and FBOs at KRPX

No public API publishes FBO fuel prices, so JetDesk does not guess. Pilots and crews log the price they actually paid at KRPX, 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 KRPX or read what a fuel stop actually saves.

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