10_Cost_Index_web

Cost Index 16
Cost Index As A Function Of LRC, MRC
767-200 JT9D-7R4D
Cost Index
17
Economy Cruise Speed
767-200 JT9D-7R4D
Cost Index
18
Typical Cost Indices For Boeing Airplanes
= 40
Cost index is the relative importance of time cost compared to fuel cost
Cost Index 19
Cost Comparison Between Different Airplanes
For both airplanes, assume: • MRC = 0.77 Mach, LRC = 0.80 Mach • FM variation with Mach is the same • Cost of time = $600/hr • Cost of Fuel = $300/ton (15¢/lb) • “Large” Airplane FM = 0.05 NAM/lb @ MRC • “Small” Airplane FM = 0.08 NAM/lb @ MRC
MIN FUEL ECON VMO/MMO
Speed
Cost Index 8
Economy Speed Sample Calculation
• 767-200 at 35,000 feet • Weight - 310,000 pounds • Time-related costs - $500 per flight-hour • Fuel costs - $.10 per pound
Cost index =
=
= 80 =
=
If $1.00 = 7.3 pesos, then: Flight hour cost = $800/hour x 7.3 pesos/$ = 5,840 pesos/hour Fuel cost = $.10/pounds x 7.3 pesos/$ = .73 pesos/pound
$340 $336 $334 $336 $350 Time-related cost (Time-hours x $500) Fuel cost (pounds x $.10)
Cost
Cost Index
.75
.77
.79
.81
.83
10
How Economy Speed Is Determined
Cost Index
21
Cost Comparison Between Different Airplanes
Cost index =
Time-related cost ($ / flight-hour) Fuel cost (cents / pound)
Cost index =
$600/hr 15¢/lb
A fixed descent speed is used (does not change as fuel burns off)
11
Cost Index Defined
Cost index =
Time-related cost ($ / flight-hour) Fuel cost (cents / pound)
0 25 0 90 80 140
0 MRC
Fuel mileage (miles per gallon)
(747) 150 0 15 180 55 (777) 0 15 80 50 (767) 70 10 (757) 30 35 LRC
Typical airline values
(737)
Cruise mach number
Cost Index
14
The Common Way
• Determine the value of cost index that approximates LRC in typical cruise conditions • Decide where you want to operate in relation to MRC, LRC
Cost Index
15
MRC Versus LRC
2-4%
Fuel Mileage
(miles per 1,000 pounds of fuel)
MRC Cost Index = 0
1%
LRC
Cruise Speed MRC = Maximum range cruise (speed for best fuel mileage) LRC = Long range cruise (speed for 99% of best fuel mileage)
Descent
D
Economy speed is the speed at which the fuel cost plus time cost from “A” to “B” is minimized Includes some cruise operation A fixed climb speed is used (does not change as fuel burns off)
Cost Index
Economy speed is the speed at which the fuel cost plus time cost from “C” to “D” is minimized Includes some cruise operation
Speed changes as fuel burns off
– The common way – The right way
• Some commonly-asked questions
Cost Index
4
Time-Related Costs
• Direct airplane operating costs are affected by flight time (a reduction / increase in speed results in a proportional increase / reduction in cost) • Flight crew • Cabin crew • Leasing • Maintenance – Airframe material – Airframe labor – Engine material – Engine labor • Others – Expressed in units of currency per flight-hour ($/hour) • May be difficult to determine
1
Selecting The Best Cost Index
Cost Index
2
Purpose
• There are many factors involved in selecting the best cost index for use by the airplane’s flight management computer • This presentation provides some information that should be helpful in the selection process
Cruise speed M (.78) Climb speed (KIAS)
260 280 300BBiblioteka M (.80) M (.82)
C
Descent speed (KIAS)
220 240 260
A
Climb
Cruise
Economy speed is the speed at which the fuel cost plus time cost from “B” to “C” is minimized
.81 .214 2,294 107 229 $336
.83 .209 2,451 105 245 $350
9
Cost To Fly A 100 NM Cruise Segment
• 767-200 at 35,000 feet • Weight - 310,000 pounds • Time-related costs - $500 per flight-hour • Fuel costs - $.10 per pound
FLIGHT OPERATIONS ENGINEERING
Cost Index
Performance Engineer Operations Flight Operations Engineering
Dick Mayward
Performance Engineering Operations
Boeing Commercial Airplanes June 2004
100 NM
Mach Time-hours Fuel-pounds Cost Time-related Fuel Total
Cost Index
.75 .231 2,242 116 224 $340
.77 .225 2,230 113 223 $336
.79 .220 2,235 110 224 $334
Cost Index 12
Example
Given: Flight hour cost = $800/hour Fuel cost = 10 cents/pound = $.10/pound
$/hour Cents/pound 800 10 $800 $.10 x 100 Units of currency/hour Units of currency/pound x 100