KJNX · Johnston Regional Airport

SMITHFIELD, NORTH CAROLINA · MEDIUM AIRPORT

164

Elevation ft

Runway

5,500

Longest ft · 03/21

35.54N

78.39W

Johnston Regional Airport serves Smithfield, North Carolina at 164 ft elevation with its longest runway, 03/21, at 5,500 by 100 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 KJNX in JetDesk: live METAR, TAF, winds and runway verdict →

01Runways

Runway	Length × width	Surface	Lighting
03/21	5,500 × 100 ft	asphalt	lit

02Density altitude and turboprop runway margins

Standard temperature at 164 ft is about 15°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, 15°C)	164 ft	2,470 ft	2,127 ft	3,191 ft
Warm day (ISA +10)	1,364 ft	2,704 ft	2,254 ft	3,381 ft
Hot day (ISA +20)	2,564 ft	2,938 ft	2,381 ft	3,571 ft
35°C afternoon	2,603 ft	2,946 ft	2,385 ft	3,577 ft

Planning aid only. Even on a 35°C afternoon the longest runway (03/21, 5,500 ft) covers a Meridian-class turboprop's landing distance with a 50 percent margin (3,577 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 KJNX is high, or as the longer runway on a hot afternoon.

Airport	Distance	Longest runway
KHRJ Harnett Regional Jetport Airport	19 nm SW	5,005 ft
KGWW Wayne Executive Jetport	21 nm E	5,501 ft
W40 Mount Olive Municipal Airport	26 nm SE	5,254 ft
KRDU Raleigh-Durham International Airport	28 nm NW	10,000 ft
KLHZ Triangle North Executive Airport	29 nm N	5,498 ft

04Jet A prices and FBOs at KJNX

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

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