Helena Regional to Bozeman Yellowstone International HLN → BZN
61 nautical miles (70 statute miles) southeast on a straight line, true course 145°, about 133° magnetic at the departure end (variation 12E). At 120 knots that is 31 min at the quickest height in today's winds (5,500 ft, a 3-knot headwind), arriving about 12:44 am MDT (06:44 UTC), after sunset at the destination. Right now HLN is VFR, wind from the west (270°) at 8 knots; BZN is low IFR, wind from the west (270°) at 5 knots. For planning, not a briefing: the legal preflight briefing comes from Flight Service (1-800-WX-BRIEF) or the FAA's own tools. Airlines fly this pair: 2 flights in the DOT's last twelve reported months, the route's page.
The route the straight line, the warnings crossed, restrictions, pilot reports and the airports along the way · click a mark for its words
Green, blue, red and purple airport dots are the flying conditions reported there now (VFR, marginal VFR, IFR, low IFR); grey means no report. Red areas are SIGMETs, orange areas AIRMETs, hatched red areas temporary flight restrictions. Map tiles: OpenFreeMap, data © OpenStreetMap contributors.
Warnings the route crosses SIGMETs and AIRMETs whose area the line passes through or comes within 25 nm of
- AIRMET SIERRA 4E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the whole route.
- AIRMET ZULU 2C: moderate icing up to 23,000 ft. Over the whole route.
- AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the first 52 nm of the route.
- AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the whole route.
A SIGMET warns of weather hazardous to all aircraft; an AIRMET of weather that matters to small aircraft and to flying without instruments. "From 60 to 180 nm out" is measured along the route from HLN.
Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first
- B737 , 0 nm northwest, 11:31 pm MDT (05:31 UTC): remarks: saw the light at 500FT braking good no icing. At the destination end, 0 nm northwest of the line.
as filed, and in English
BZN UA /OV BZN/TM 0531/FLBURD/TP B737/RM SAW THE LIGHT AT 500FT. BRAKING GOOD. NEG ICING
- Report
- a routine report filed through BZN
- Where
- over BZN
- Time
- 05:31 UTC
- Height
- at BURD
- Aircraft
- B737
- Remarks
- saw the light at 500FT braking good no icing
- GLF5 descending, 0 nm northwest, 9:46 pm MDT (03:46 UTC): remarks: broke out 100-150FT above ground. At the destination end, 0 nm northwest of the line.
as filed, and in English
BZN UA /OV BZN/TM 0346/FLDURD/TP GLF5/RM BROKE OUT 100-150FT AGL
- Report
- a routine report filed through BZN
- Where
- over BZN
- Time
- 03:46 UTC
- Height
- during the descent
- Aircraft
- GLF5
- Remarks
- broke out 100-150FT above ground
Winds aloft along the route, and the time en route the forecast for use 02:00–09:00 UTC · at 120 knots true airspeed
The eastbound cruising heights for this course (VFR: odd thousands plus 500 ft; above 18,000 ft the forecast levels), with the wind averaged along the line from the 2 forecast points nearest it (GTF, DLN). A plus sign is a headwind, a minus sign a tailwind.
| Height | Average wind | Head- or tailwind | Temperature | Ground speed | Time en route | Arrival |
|---|---|---|---|---|---|---|
| 5,500 ft | 070° at 11 kt | +3 kt | 117 kt | 31 min | 12:44 am MDT (06:44 UTC) | |
| 7,500 ft | 080° at 11 kt | +4 kt | -6 °C | 116 kt | 32 min | 12:45 am MDT (06:45 UTC) |
| 9,500 ft | 090° at 11 kt | +6 kt | -7 °C | 114 kt | 32 min | 12:45 am MDT (06:45 UTC) |
| 11,500 ft | 130° at 10 kt | +10 kt | -8 °C | 110 kt | 33 min | 12:46 am MDT (06:46 UTC) |
| 13,500 ft | 160° at 13 kt | +12 kt | -9 °C | 108 kt | 34 min | 12:47 am MDT (06:47 UTC) |
| 15,500 ft | 180° at 18 kt | +14 kt | -12 °C | 106 kt | 35 min | 12:48 am MDT (06:48 UTC) |
| 17,500 ft | 200° at 25 kt | +16 kt | -14 °C | 104 kt | 35 min | 12:48 am MDT (06:48 UTC) |
| 18,000 ft FL180 | 200° at 27 kt | +17 kt | -15 °C | 103 kt | 36 min | 12:49 am MDT (06:49 UTC) |
| 24,000 ft FL240 | 200° at 42 kt | +21 kt | -24 °C | 99 kt | 37 min | 12:50 am MDT (06:50 UTC) |
| 30,000 ft FL300 | 200° at 57 kt | +30 kt | -38 °C | 90 kt | 41 min | 12:54 am MDT (06:54 UTC) |
| 34,000 ft FL340 | 220° at 70 kt | +22 kt | -39 °C | 98 kt | 37 min | 12:50 am MDT (06:50 UTC) |
| 39,000 ft FL390 | 220° at 77 kt | +20 kt | -43 °C | 100 kt | 37 min | 12:50 am MDT (06:50 UTC) |
Based on data from the 12th at 00:00 UTC; valid on the 12th at 06:00 UTC for use 02:00 to 09:00 UTC; temperatures above 24,000 ft are below zero. Heights are above sea level; a height is left out when the forecast has no wind for it over most of the line (the ground is higher). Ground speed is the airspeed less the headwind; the time en route is for the straight line and ignores climb, descent and routing around weather.
The forecast points as issued
| Point | From | 3,000 | 6,000 | 9,000 | 12,000 | 18,000 | 24,000 | 30,000 | 34,000 | 39,000 |
|---|---|---|---|---|---|---|---|---|---|---|
| GTF | used from 0 nm out; 72 nm from the line | 070/11 | 080/15 -7° | 110/19 -9° | 190/25 -14° | 200/34 -23° | 200/54 -39° | 220/66 -40° | 220/77 -44° | |
| DLN | used from 43 nm out; 66 nm from the line | 090/6 -6° | 240/22 -4° | 210/34 -16° | 210/62 -25° | 210/66 -34° | 210/82 -36° | 220/77 -42° |
The weather now: both ends and the airports along the way public airports with a weather report within 25 nm of the line, one for each stretch
| Airport | Where | Conditions | Wind | Visibility | Ceiling | Elevation | Reported |
|---|---|---|---|---|---|---|---|
| HLN Helena, MT | departure | VFR Sky: a few clouds at 2,100 feet, overcast at 5,000 feet | from the west (270°) at 8 knots | 10+ mi | 5,000 ft | 3,877 ft | 11:53 pm MDT (05:53 UTC) |
| BZN Bozeman, MT | destination | low IFR Sky: overcast at 200 feet Weather: light snow, mist | from the west (270°) at 5 knots | 2.5 mi | 200 ft | 4,473 ft | 11:56 pm MDT (05:56 UTC) |
The highest airport on this list sits at 4,473 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.
At BZN when you get there the forecast at the estimated arrival, 12:44 am MDT (06:44 UTC)
Wind light and variable, visibility 2 miles, light snow, a broken layer at 200 feet, overcast at 1,000 feet low IFR
The whole forecast for BZN
- From Mon 12:00 am MDT (06:00 UTC): wind light and variable, visibility 2 miles, light snow, a broken layer at 200 feet, overcast at 1,000 feet
- From Mon 3:00 am MDT (09:00 UTC): wind light and variable, visibility 6 miles, mist, overcast at 800 feet
- From Mon 10:00 am MDT (16:00 UTC): wind light and variable, visibility more than 6 miles, scattered clouds at 800 feet, overcast at 1,000 feet
- From Mon 2:00 pm MDT (20:00 UTC): wind light and variable, visibility more than 6 miles, scattered clouds at 800 feet, a broken layer at 1,500 feet
- From Mon 6:00 pm MDT (00:00 UTC): wind light and variable, visibility 6 miles, mist, scattered clouds at 800 feet, a broken layer at 2,000 feet
The forecast for HLN, the departure
- From Mon 12:00 am MDT (06:00 UTC): wind from the west-northwest at 14 knots, visibility 3 miles, light snow, overcast at 3,500 feet
- At times between Mon 12:00 am MDT (06:00 UTC) and 3:00 am MDT (09:00 UTC): visibility 1 mile, light snow, overcast at 1,500 feet
- From Mon 3:00 am MDT (09:00 UTC): wind light and variable, visibility more than 6 miles, overcast at 1,500 feet
- 30% chance between Mon 3:00 am MDT (09:00 UTC) and 6:00 am MDT (12:00 UTC): visibility 3 miles, light snow, overcast at 1,000 feet
- From Mon 3:00 pm MDT (21:00 UTC): wind light and variable, visibility more than 6 miles, scattered clouds at 1,500 feet, scattered clouds at 3,500 feet
Temporary flight restrictions on the line or within 25 nm of it
No temporary flight restriction on or near this route right now.
Daylight
Sunset at HLN 6:45 pm MDT (00:45 UTC), at BZN 6:42 pm MDT (00:42 UTC) (civil twilight ends 7:12 pm MDT (01:12 UTC)). At 120 knots the arrival at BZN is before sunrise there (7:36 am MDT (13:36 UTC)).
Each restriction opens the FAA's own page with the exact area, heights and times. Ordinary notices to air missions (closed runways, lights out) are not shown: the FAA's notice search is not open to sites like this one at this time.
Radar and forecast charts for the regions crossed government pictures, the latest each time the page loads
Sources: the Aviation Weather Center's data service (SIGMETs, AIRMETs, graphical AIRMETs, pilot reports, winds and temperatures aloft, observations and terminal forecasts), the National Weather Service radar, the Weather Prediction Center's charts, the FAA's temporary flight restriction list and shapes, and the FAA's airport file for the positions, elevations and magnetic variation. Fetched when the page is viewed and kept a few minutes. Each leg is the straight line between its two airports; airways, terrain and airspace are not considered. The airports in detail: Helena Regional, Bozeman Yellowstone International.