RUNWAYS
Runway Length Requirements
 Governmental regulations
 Airport location
 Critical aircraft
 Sources:
http://www.faa.gov/arp/150acs.cfm?ARPnav=
acs
Runway Pavement Components
 Full strength (FS)

Take-off & Landing
 Partial strength (PS)

Take-off
 Clear Way (CL)

Take-off
Length Conditions
 Normal take-off
 Engine failure


Continue take-off
Abort take-off
 Landing
Some Terms (see fig 3-22)
 Lift off distance (LOD)

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)
Relationship of Distances
35’
LOD
D35
TOD
Normal Take-Off
35’
LODN
D35,N
TODN = 1.15 D35,N
Clear Zone (CLN,max) = 0.5(TODN -1.15 LODN)
TORN = TODN – CLN = FSN
FSN
TODN
CLN
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
TODE
CLE
Engine Failure, Abort
Engine fails at V=V1
Stop
DAS
TODA = DAS
V1 = speed above which you
continue to take off
V2 = rotation or lift off speed
FSA
TODA
PSA
Landing
Stop
50’
SD
FS = “Runway”
LD
LD = SD/0.6
LD = FSL
FSL
Runway Layout
CL
PS
PS (partial strength) = SW (stopway)
PS
FS = “Runway”
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}
CL max= 1000 ft
CLmin = 0 ft
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
Example
Normal take-off
TODN = 1.15(7000)= 8,050 ft
(2/3)
Engine failure, abort
DAS = 7,900 ft
CLN,max = 0.5(8050 -1.15(6000))
= 575 ft
FSN = 8050-575 = 7,475 ft
Engine failure, continue
Landing
TODE = 8,200 ft
LD = 4500/0.60 =7,500 ft
CLE,max = 0.5(8200 - 7000) =600 ft
FSL = 7,500 ft
FSE = 8200- 600 = 7,600 ft
Example
(3/3)
FL = max {8050, 8200, 7900, 7500} = 8,200 ft
FS = max {7475, 7600, 7500} = 7,600 ft
PS = 7900-7600 = 300 ft
CL = min {8200-7900, 575, 600} = 300 ft
300
300
7600
8800
8200
300 300
Airport Location Adjustments
 Elevation


7% per 1,000 ft
Fe = 0.07 E + 1; E in 000’s
 Temperature

Ft =0.01[T –(15-1.981E)]+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)
Critical Aircraft Requirements
 Runway length affects


Take-off weight
Landing weight
 Runway lengths


Take off
Landing
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)
Example
(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 737-200.
Determine:
1. Runway length without weight limits
2. Weight limits for an 8,000 ft runway
Runway length without weight limits
Source: AC 150/5325-4A
(2/8)
Example
(3/8)
100.4
Example
(4/8)
69.5
Example
(5/8)
69.5
100.4
Runway 8,545 ft w/0% grade MTOW 100,400 lbs
Example
(6/8)
Runway 5,650 ft
w/0% grade, MLW 103,000
Example with 8000 foot R/W
69.5
MTOW
97,160 lbs
Runway 8,000 ft
(7/8)
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/
50 pax @ 1240 miles
60 pax @ 1090miles
75 pax @ 860 miles