Plan a flight · Sun 7:40 pm PDT (02:40 UTC)

San Francisco International to MC Ghee Tyson Airport SFO → TYS

1,838 nautical miles (2,115 statute miles) east on a straight line, true course 081°, about 067° magnetic at the departure end (variation 14E). At 120 knots that is 11 h 04 min at the quickest height in today's winds (34,000 ft, a 46-knot tailwind), arriving about 9:44 am EDT (13:44 UTC). Right now SFO is VFR, wind from the west-southwest (250°) at 9 knots; TYS is marginal VFR, wind from the west-southwest (250°) at 12 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

SIGMET W10W: thunderstorms (a convective SIGMET) up to 30,000 ft, moving from the southwest at 20 knots, until 8:55 pm PDT (03:55 UTC). Over the route from 220 to 270 nm out.
as issued
```
WSUS33 KKCI 120155
MKCW WST 120155
CONVECTIVE SIGMET 10W
VALID UNTIL 0355Z
NV
FROM 70SW TWF-40NNW BVL-40SW ELY-30ESE OAL-40WNW OAL-70SW TWF
AREA TS MOV FROM 23020KT. TOPS TO FL300.
```

SIGMET 6W: thunderstorms (a convective SIGMET) up to 34,000 ft, moving from the southwest at 40 knots, until 8:55 pm PDT (03:55 UTC). Over the route from 719 to 859 nm out.

as issued

WSUS33 KKCI 120155
MKCW WST 120155
CONVECTIVE SIGMET 6W
VALID UNTIL 0355Z
CO NM
FROM 50SSW DEN-30NNE TBE-50SSW CME-50E SJN-20NE DVC-50SSW DEN
AREA TS MOV FROM 23040KT. TOPS TO FL340.

AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 39,000 ft. Over the first 40 nm of the route.
AIRMET TANGO 3W: moderate turbulence below 18,000 ft (due to mountain wave) up to 15,000 ft. Over the route from 130 to 260 nm out.
AIRMET ZULU 3C: moderate icing up to 22,000 ft. Over the route from 220 to 619 nm out.
AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the route from 240 to 869 nm out.
AIRMET TANGO 4W: moderate turbulence below 18,000 ft up to 18,000 ft. Over the route from 280 to 899 nm out.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 300 to 619 nm out.
AIRMET SIERRA 2E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the route from 439 to 539 nm out.
AIRMET TANGO 1W: low-level wind shear (due to air speed loss or gain of 20 knots or more below 2,000 ft above the ground). Over the route from 609 to 799 nm out.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 709 to 799 nm out.
AIRMET TANGO 3W: low-level wind shear (due to air speed loss or gain of 20 knots or more below 2,000 ft above the ground). Over the route from 919 to 1258 nm out.
AIRMET SIERRA 3E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the route from 1778 to 1818 nm out.
AIRMET SIERRA 4E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the last 50 nm of the 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 SFO.

Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first

urgent B407 at 10,000 ft, 28 nm north, 7:13 pm PDT (02:13 UTC): moderate to severe turbulence. 829 nm along the route, 28 nm north of the line.
as filed, and in English
```
COS UUA /OV 10 W COS/TM 0213/FL100/TP B407/TB MDT-SEV
```
Report
an urgent report filed through COS
Where
10 west cos
Time
02:13 UTC
Height
at 10,000 ft
Aircraft
B407
Turbulence
mdt-sev
E170 at 10,000 ft, 33 nm north, 4:41 pm PDT (23:41 UTC): moderate turbulence up to 10,000 ft, remarks: during the climb. 659 nm along the route, 33 nm north of the line.
as filed, and in English
```
GJT UA /OV GJT144009/TM 2341/FL100/TP E170/TB MOD SFC-100/RM DURC
```
Report
a routine report filed through GJT
Where
9 nm southeast (144°) of GJT
Time
23:41 UTC
Height
at 10,000 ft
Aircraft
E170
Turbulence
moderate from the surface to 10,000 ft
Remarks
during the climb
SW4 at 15,000 ft, 41 nm south, 6:39 pm PDT (01:39 UTC): moderate turbulence, light rime icing, freezing, rain, 0 °C, remarks: instrument conditions ZDVWC-36. 679 nm along the route, 41 nm south of the line.
as filed, and in English
```
CEZ UA /OV CEZ030030/TM 0139/FL150/TP SW4/SK BASE150/WX FZ RA/TA 00/TB CONS MOD/IC LGT RIME/RM IMC ZDVWC-36
```
Report
a routine report filed through CEZ
Where
30 nm northeast (030°) of CEZ
Time
01:39 UTC
Height
at 15,000 ft
Aircraft
SW4
Sky
BASE150
Weather
freezing, rain
Temperature
0 °C
Turbulence
continuous moderate
Icing
light rime
Remarks
instrument conditions ZDVWC-36
UAL2238 at 38,000 ft, 18 nm south, 4:44 pm PDT (23:44 UTC): moderate turbulence, wind 244° at 64 knots. 739 nm along the route, 18 nm south of the line.
as filed, and in English
```
ARP UAL2238 3807N 10649W 2344 F380 244/064KT TB CONT MOD TURB IC
```
Report
a routine report filed through ARP
BE9L at 24,500 ft, 14 nm south, 7:21 pm PDT (02:21 UTC): moderate turbulence, remarks: ZDVWC-41. 809 nm along the route, 14 nm south of the line.
as filed, and in English
```
PUB UA /OV PUB250040/TM 0221/FL245/TP BE9L/TB OCNL MOD/RM ZDVWC-41
```
Report
a routine report filed through PUB
Where
40 nm west (250°) of PUB
Time
02:21 UTC
Height
at 24,500 ft
Aircraft
BE9L
Turbulence
occasional moderate
Remarks
ZDVWC-41
B738 at 18,000 ft, 38 nm north, 7:02 pm PDT (02:02 UTC): moderate chop turbulence from 18,000 ft to 25,000 ft, remarks: during the climb ZDVWC-41. 809 nm along the route, 38 nm north of the line.
as filed, and in English
```
COS UA /OV BRK270030/TM 0202/FL180/TP B738/TB MOD CHOP 180-250/RM DURC ZDVWC-41
```
Report
a routine report filed through COS
Where
30 nm west (270°) of BRK
Time
02:02 UTC
Height
at 18,000 ft
Aircraft
B738
Turbulence
moderate chop from 18,000 ft to 25,000 ft
Remarks
during the climb ZDVWC-41
B738 at 35,000 ft, 37 nm south, 5:14 pm PDT (00:14 UTC): remarks: zdvwc. 639 nm along the route, 37 nm south of the line.
as filed, and in English
```
CEZ UA /OV DVC/TM 0014/FL350/TP B738/SK TOP 310/RM ZDVWC
```
Report
a routine report filed through CEZ
Where
over DVC
Time
00:14 UTC
Height
at 35,000 ft
Aircraft
B738
Sky
top 31,000 ft
Remarks
zdvwc
LJ60 at 15,000 ft, 27 nm north, 5:28 pm PDT (00:28 UTC): light to moderate icing from 16,500 ft to 19,000 ft, -13 °C, remarks: during the descent zdvwc. 709 nm along the route, 27 nm north of the line.
as filed, and in English
```
MTJ UA /OV MTJ030030/TM 0028/FL150/TP LJ60/TA M13/IC LGT-MOD 190-165/RM DURD ZDVWC
```
Report
a routine report filed through MTJ
Where
30 nm northeast (030°) of MTJ
Time
00:28 UTC
Height
at 15,000 ft
Aircraft
LJ60
Temperature
−13 °C
Icing
light to moderate from 19,000 ft to 16,500 ft
Remarks
during the descent zdvwc
SW4 at 20,000 ft, 7 nm north, 6:00 pm PDT (01:00 UTC): light rime icing, 0 °C, remarks: ZDVWC-12. 729 nm along the route, 7 nm north of the line.
as filed, and in English
```
GUC UA /OV GUC/TM 0100/FL200/TP SW4/TA 00/IC LGT RIME/RM ZDVWC-12
```
Report
a routine report filed through GUC
Where
over GUC
Time
01:00 UTC
Height
at 20,000 ft
Aircraft
SW4
Temperature
0 °C
Icing
light rime
Remarks
ZDVWC-12
BE9L at 20,000 ft, 30 nm south, 5:34 pm PDT (00:34 UTC): light rime icing, -9 °C, remarks: ZDVWC-41. 779 nm along the route, 30 nm south of the line.
as filed, and in English
```
ALS UA /OV ALS330035/TM 0034/FL200/TP BE9L/TA M09/IC LGT RIME/RM ZDVWC-41
```
Report
a routine report filed through ALS
Where
35 nm northwest (330°) of ALS
Time
00:34 UTC
Height
at 20,000 ft
Aircraft
BE9L
Temperature
−9 °C
Icing
light rime
Remarks
ZDVWC-41
B38M at 36,000 ft, 29 nm south, 7:22 pm PDT (02:22 UTC): light turbulence, remarks: mtw +/-200FT ZDVWC-30. 789 nm along the route, 29 nm south of the line.
as filed, and in English
```
ALS UA /OV ALS360035/TM 0222/FL360/TP B38M/TB LGT/RM MTW +/-200FT ZDVWC-30
```
Report
a routine report filed through ALS
Where
35 nm north (360°) of ALS
Time
02:22 UTC
Height
at 36,000 ft
Aircraft
B38M
Turbulence
light
Remarks
mtw +/-200FT ZDVWC-30
CL35 at 43,000 ft, 14 nm south, 5:21 pm PDT (00:21 UTC): remarks: mtw +/-300FT zdvwc. 809 nm along the route, 14 nm south of the line.
as filed, and in English
```
PUB UA /OV PUB250040/TM 0021/FL430/TP CL35/RM MTW +/-300FT ZDVWC
```
Report
a routine report filed through PUB
Where
40 nm west (250°) of PUB
Time
00:21 UTC
Height
at 43,000 ft
Aircraft
CL35
Remarks
mtw +/-300FT zdvwc
E55P at 38,000 ft, 44 nm north, 6:23 pm PDT (01:23 UTC): light chop turbulence, remarks: ZDVWC-05. 819 nm along the route, 44 nm north of the line.
as filed, and in English
```
DEN UA /OV FQF200040/TM 0123/FL380/TP E55P/TB LGT CHOP/RM ZDVWC-05
```
Report
a routine report filed through DEN
Where
40 nm south (200°) of FQF
Time
01:23 UTC
Height
at 38,000 ft
Aircraft
E55P
Turbulence
light chop
Remarks
ZDVWC-05
GLF6 at 40,000 ft, 46 nm north, 5:48 pm PDT (00:48 UTC): light to moderate chop turbulence, remarks: ZDVWC-46. 829 nm along the route, 46 nm north of the line.
as filed, and in English
```
COS UA /OV COS340020/TM 0048/FL400/TP GLF6/TB LGT-MOD CHOP/RM ZDVWC-46
```
Report
a routine report filed through COS
Where
20 nm north (340°) of COS
Time
00:48 UTC
Height
at 40,000 ft
Aircraft
GLF6
Turbulence
light to moderate chop
Remarks
ZDVWC-46

8 more routine reports are on the map.

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 16 forecast points nearest it (SFO, SAC, FAT, BIH, ELY, BCE, GJT, ALS, PUB, GCK, ICT, TUL, SGF, CGI, BNA, TYS). 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	240° at 17 kt	−13 kt	21 °C	133 kt	13 h 49 min	12:29 pm EDT (16:29 UTC)
7,500 ft	230° at 20 kt	−15 kt	11 °C	135 kt	13 h 37 min	12:17 pm EDT (16:17 UTC)
9,500 ft	240° at 18 kt	−16 kt	8 °C	136 kt	13 h 31 min	12:11 pm EDT (16:11 UTC)
11,500 ft	240° at 19 kt	−17 kt	4 °C	137 kt	13 h 25 min	12:05 pm EDT (16:05 UTC)
13,500 ft	240° at 20 kt	−18 kt	0 °C	138 kt	13 h 19 min	11:59 am EDT (15:59 UTC)
15,500 ft	240° at 22 kt	−20 kt	-4 °C	140 kt	13 h 08 min	11:48 am EDT (15:48 UTC)
17,500 ft	240° at 24 kt	−21 kt	-9 °C	141 kt	13 h 02 min	11:42 am EDT (15:42 UTC)
18,000 ft FL180	240° at 25 kt	−21 kt	-10 °C	141 kt	13 h 02 min	11:42 am EDT (15:42 UTC)
24,000 ft FL240	240° at 31 kt	−28 kt	-21 °C	148 kt	12 h 25 min	11:05 am EDT (15:05 UTC)
30,000 ft FL300	250° at 43 kt	−41 kt	-30 °C	161 kt	11 h 25 min	10:05 am EDT (14:05 UTC)
34,000 ft FL340	250° at 46 kt	−46 kt	-37 °C	166 kt	11 h 04 min	9:44 am EDT (13:44 UTC)
39,000 ft FL390	260° at 39 kt	−40 kt	-47 °C	160 kt	11 h 29 min	10:09 am EDT (14:09 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
SFO	used from 0 nm out; 25 nm from the line	120/13	090/14 5°	040/14 -1°	350/17 -5°	360/42 -14°	360/64 -23°	350/38 -32°	300/19 -37°	250/18 -44°
SAC	used from 50 nm out; 54 nm from the line	110/6	L/V 4°	010/11 -2°	350/11 -7°	340/24 -16°	360/44 -23°	330/24 -30°	270/21 -35°	230/23 -43°
FAT	used from 100 nm out; 67 nm from the line	130/16	160/20 5°	190/28 -1°	210/25 -5°	220/27 -15°	230/21 -26°	220/42 -29°	220/44 -35°	220/44 -44°
BIH	used from 150 nm out; 41 nm from the line		L/V	240/7 1°	190/13 -3°	200/26 -16°	210/43 -26°	220/54 -28°	220/51 -35°	220/47 -43°
ELY	used from 300 nm out; 73 nm from the line			200/39 3°	210/27 -2°	210/45 -15°	220/56 -24°	210/60 -28°	210/63 -34°	220/61 -43°
BCE	used from 399 nm out; 72 nm from the line				220/27 -1°	210/40 -13°	220/54 -21°	220/64 -30°	220/64 -34°	220/52 -44°
GJT	used from 549 nm out; 92 nm from the line			210/43 7°	230/45 1°	220/49 -12°	220/62 -22°	220/59 -28°	230/60 -33°	220/55 -45°
ALS	used from 749 nm out; 59 nm from the line				230/37 4°	220/54 -9°	230/62 -22°	240/77 -26°	240/74 -33°	230/59 -45°
PUB	used from 799 nm out; 22 nm from the line			230/25 13°	230/32 6°	220/44 -8°	230/49 -21°	240/70 -28°	240/67 -34°	240/58 -46°
GCK	used from 949 nm out; 54 nm from the line		220/48 21°	230/37 14°	250/30 8°	230/37 -6°	240/37 -20°	240/69 -28°	250/67 -37°	260/58 -48°
ICT	used from 1099 nm out; 61 nm from the line	200/48	230/39 19°	240/24 14°	240/20 8°	240/22 -6°	250/31 -18°	250/61 -29°	260/58 -38°	270/54 -49°
TUL	used from 1248 nm out; 92 nm from the line	210/37	240/29 17°	260/15 14°	260/11 7°	240/22 -6°	250/29 -16°	270/45 -29°	270/47 -40°	280/44 -50°
SGF	used from 1298 nm out; 55 nm from the line	230/33	230/28 15°	250/20 13°	240/18 7°	250/20 -6°	250/24 -17°	280/42 -31°	280/49 -40°	290/46 -51°
CGI	used from 1448 nm out; 86 nm from the line	240/20	270/15 15°	280/15 11°	300/13 6°	290/20 -6°	280/24 -18°	300/34 -32°	300/47 -41°	310/49 -51°
BNA	used from 1648 nm out; 36 nm from the line	310/20	340/20 17°	330/24 10°	340/22 5°	330/26 -6°	340/29 -18°	330/52 -33°	320/62 -41°	340/45 -50°
TYS	used from 1748 nm out; 65 nm from the line	320/20	340/18 11°	340/32 9°	340/36 4°	330/37 -7°	330/38 -19°	330/50 -34°	330/53 -38°	330/44 -48°

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
SFO San Francisco, CA	departure	VFR Sky: a few clouds at 2,000 feet	from the west-southwest (250°) at 9 knots	10+ mi	none	13 ft	6:56 pm PDT (01:56 UTC)
LVK Livermore, CA	30 nm out, 3 nm west of the line, tower	VFR	from the west (280°) at 11 knots	10+ mi	none	399 ft	01:53 UTC
TPH Tonopah, NV	250 nm out, 5 nm southeast of the line	VFR	from the south (180°) at 18 knots, gusting to 26	10+ mi	none	5,430 ft	01:56 UTC
HVE Hanksville, UT	549 nm out, 5 nm east of the line	VFR Sky: a broken layer at 6,500 feet	from the southeast (130°) at 11 knots, gusting to 14	10+ mi	6,500 ft	4,453 ft	02:10 UTC
MTJ Montrose, CO	689 nm out, 6 nm northwest of the line	VFR Sky: scattered clouds at 11,000 feet	from the southwest (230°) at 8 knots	10+ mi	none	5,758 ft	01:53 UTC
PUB Pueblo, CO	849 nm out, 5 nm southwest of the line, tower	VFR Sky: scattered clouds at 11,000 feet	from the west-southwest (250°) at 25 knots, gusting to 37	10+ mi	none	4,729 ft	01:53 UTC
GCK Garden City, KS	1029 nm out, 15 nm south of the line, tower	VFR	from the south (170°) at 11 knots	10+ mi	none	2,890 ft	01:54 UTC
HUT Hutchinson, KS	1158 nm out, 7 nm north of the line, tower	VFR	from the south (170°) at 14 knots	10+ mi	none	1,542 ft	01:52 UTC
SGF Springfield, MO	1378 nm out, 12 nm south of the line, tower	VFR	from the south (180°) at 7 knots	10+ mi	none	1,268 ft	01:52 UTC
PAH Paducah, KY	1598 nm out, 19 nm north of the line, tower	VFR	calm	10+ mi	none	410 ft	00:00 UTC
JWN Nashville, TN	1698 nm out, 13 nm south of the line, tower	VFR	calm	8 mi	none	501 ft	02:15 UTC
TYS Knoxville, TN	destination	marginal VFR Sky: a broken layer at 1,300 feet, overcast at 2,700 feet	from the west-southwest (250°) at 12 knots	10+ mi	1,300 ft	986 ft	9:53 pm EDT (01:53 UTC)

The highest airport on this list sits at 5,758 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

At TYS when you get there the forecast at the estimated arrival, 9:44 am EDT (13:44 UTC)

Wind light and variable, visibility more than 6 miles, a few clouds at 3,500 feet, scattered clouds at 25,000 feet VFR

The whole forecast for TYS

From Sun 8:00 pm EDT (00:00 UTC): wind from the west-southwest at 9 knots, visibility more than 6 miles, scattered clouds at 1,000 feet, a broken layer at 1,500 feet
From Mon 3:00 am EDT (07:00 UTC): wind from the southwest at 7 knots, visibility more than 6 miles, a broken layer at 2,500 feet
From Mon 8:00 am EDT (12:00 UTC): wind light and variable, visibility more than 6 miles, a few clouds at 3,500 feet, scattered clouds at 25,000 feet

The forecast for SFO, the departure

From Sun 5:00 pm PDT (00:00 UTC): wind from the west-southwest at 16 knots, visibility more than 6 miles, a few clouds at 2,000 feet
From Sun 7:00 pm PDT (02:00 UTC): wind from the west-southwest at 8 knots, visibility more than 6 miles, a few clouds at 2,000 feet
From Mon 1:00 am PDT (08:00 UTC): wind from the south-southeast at 4 knots, visibility more than 6 miles, clear skies
From Mon 11:00 am PDT (18:00 UTC): wind from the east-northeast at 5 knots, visibility more than 6 miles, clear skies
From Mon 3:00 pm PDT (22:00 UTC): wind from the west at 10 knots, visibility more than 6 miles, clear skies

Temporary flight restrictions on the line or within 25 nm of it

6/7231 Santa Clara, CA, Sunday, October 11, 2026 through Monday, October 12, 2026 UTC 15 nm from the route, at the departure end · drones kept away from a public gathering · until 12 October · ZOA
6/7094 45NM NE MERCED, CA, Sunday, October 4, 2026 through Tuesday, October 20, 2026 UTC 12 nm from the route, 120 nm along the route · a hazard on the ground (fire-fighting, a chemical spill, rescue work) · until 20 October · ZOA
6/0708 Goodlettsville, TN, Saturday, August 1, 2026 through Sunday, August 1, 2027 UTC 4 nm from the route, 1698 nm along the route · security · until 1 August · ZME

Daylight

Sunset at SFO 6:36 pm PDT (01:36 UTC), at TYS 7:04 pm EDT (23:04 UTC) (civil twilight ends 7:30 pm EDT (23:30 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

Radar now, the Pacific Southwest · loop National Weather Service

Radar now, the southern Rockies · loop National Weather Service

Radar now, the southern Plains · loop National Weather Service

Radar, the whole country · loop National Weather Service

Surface analysis now Weather Prediction Center

Forecast chart, 12 hours ahead Weather Prediction Center

Forecast chart, 24 hours ahead Weather Prediction Center

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: San Francisco International, MC Ghee Tyson Airport.