1. RUNWAYS

2. Runway Length Requirements
Governmental regulations
Airport location
Critical aircraft
Source: AC 150/5325-4B - Runway Length Requirements for Airport Design

3. Runway Pavement Components
Full strength (FS)
Take-off & Landing
Partial strength (PS)
Take-off
Clear Way (CL)

4. Length Conditions Normal take-off Engine failure Landing
Continue take-off
Abort take-off
Landing

5. Some Terms (see fig 3-22) Lift off distance (LOD) D35
Threshold to wheels off the ground
D35
Threshold to aircraft 35 feet above ground
Take off distance (TOD)
Runway length provided to D35 with factor of safety applied = 1.15 D35 (for normal takeoff)
Take off roll or run (TOR)
Full strength pavement; “runway”
Accelerate and stop distance (DAS)
Landing distance (LD)

6. Relationship of Distances
35’
LOD
D35
TOD

7. Normal Take-Off TODN = 1.15 D35,N
35’
LODN
D35,N
TODN = 1.15 D35,N
Clear Zone (CLN,max) = 0.5(TODN LODN)
TORN = TODN – CLN = FSN
FSN
CLN
TODN

8. Engine Failure, Continue
Engine fails
35’
LODE
D35,E
TODE = D35,E (do not apply factor of safety)
CLE,max = 0.5(TODE - LODE)
TORE = TODE – CLE = FSE
FSE
CLE
TODE

9. Engine Failure, Abort V1 = speed above which you TODA = DAS
Engine fails at V=V1
Stop
DAS
V1 = speed above which you
continue to take off
V2 = rotation or lift off speed
TODA = DAS
FSA
PSA
TODA

10. Landing
Stop
50’ SD
FS = “Runway” LD
LD = SD/0.6
LD = FSL
FSL

11. PS (partial strength) = SW (stopway)
Runway Layout
PS (partial strength) = SW (stopway) CL PS
FS = “Runway” PS CL FL
Field Length (FL) = max {TODN,TODE, DAS, LD}
FS = max {FSN,FSE, FSL}
PS = DAS – FS PSmin = 0 ft
CL = min {FL-DAS, CLN,CLE} CLmin = 0 ft CL max= 1000 ft

12. Example (1/3) Distances for typical aircraft are as follows:
LOD: Normal 6,000 ft; Failure 7,000 ft
D35: Normal 7,000 ft; Failure 8,200 ft
DAS: 7,900 ft and SD: 4,500 ft. (LD = 4500/.6=7500)
Design the runway for bi-directional operations

13. Example (2/3) Normal take-off Engine failure, abort
TODN = 1.15(7000)= 8,050 ft
DAS = 7,900 ft
CLN,max = 0.5( (6000))
= 575 ft
FSN = = 7,475 ft
Engine failure, continue
Landing
TODE = 8,200 ft
LD = 4500/0.60 =7,500 ft
CLE,max = 0.5( ) =600 ft
FSL = 7,500 ft
FSE = = 7,600 ft

14. Example (3/3) FL = max {8050, 8200, 7900, 7500} = 8,200 ft
FS = max {7475, 7600, 7500} = 7,600 ft
PS = = 300 ft
CL = min { , 575, 600} = 300 ft
300
7600
8800
8200

15. Airport Location Adjustments
Elevation
7% per 1,000 ft
Fe = 0.07 E + 1; E in 000’s
Temperature
Ft =0.01[T –( E)]+1
Grade
Fg = 0.1 G +1
Reference length (LR) – LR from before
LR = Actual length/(Fe Ft Fg)
Or, Actual length = LR*(Fe Ft Fg)

16. Critical Aircraft Requirements
Runway length affects
Take-off weight
Landing weight
Runway lengths
Take off
Landing

17. Aircraft Weights Operating Empty Weight (OEW)
No fuel or payload
Maximum Takeoff Operating Weight (MTOW)
Maximum Landing Weight (MALW)
Maximum Structural Payload Weight (MSPW)
Maximum Zero Fuel Weight
OEW+MSPW
Fuel Weight (FW)

19. Range at Max structural payload
Payload and range with max fuel
Max range with no payload (ferry range)

20. Payload Range Plots
Max payload and reduced range if landing load is restricted (max structural landing weight)
Max range and reduced payload if landing load is restricted (max structural landing weight)

21. Example Problem 3-1

22. Example Problem 3-1

23. Example (similar to ex 3-3) (1/8)
A runway is planned for an airport at elevation 2,300 ft AMSL and average temperature of 92oF. The critical aircraft is a Boeing Determine:
Runway length without weight limits
Weight limits for an 8,000 ft runway

24. Runway length without weight limits (2/8)
Source: AC 150/5325-4A

25. Example (3/8)
100.4

26. Example (4/8)
69.5

27. Example (5/8)
69.5
100.4
Runway 8,545 ft w/0% grade MTOW 100,400 lbs

28. Example (6/8)
Runway 5,650 ft
w/0% grade, MLW 103,000 lbs

29. Example with 8000 foot R/W (7/8)
69.5
MTOW
97,160 lbs
Runway 8,000 ft

30. Example (8/8) Distance to fly from this airport? MTOW 97,160 lbs
OEW 67,238 lbs
Pax+Fuel 29, 832 lbs
225 lbs/pax Fuel 15 lbs/mi
50 pax @ 1240 miles
60 pax @ 1090miles
75 pax @ 860 miles