# Worked-Out Example of DOC: Bizjet

Based on the previous formulations, this section works out the DOC of the Bizjet example. Rather than working on an entire fleet, only one aircraft is worked out herein. Input for the DOC calculation of the Bizjet is provided herein; manhour rates are in [3]. All cost figures are in U. S. dollars and are rounded up to the next higher figure. Table 16.14 provides aircraft and engine details.

The DOC is computed for a single aircraft to obtain the trip cost rather than the per-hour cost. A lifespan of 14 years is used with a residual value of 10% of the total investment.

Aircraft Price

• Total investment = \$8 million

Utilization (per block hour per annum in hours/year)

• Utilization, U = ((5 з’™ 5) x 5.38 = 637.75 x 5.38 = 3,431 hours per year where t = block time for the mission = 5.38 hours

Fixed-Cost Elements

• Depreciation = О14х3х4306 x 5.38 = \$807 per trip

• Loan interest repayment = 0 05| 4зі 106 x 5.38 = \$665 per trip

• Insurance premium = 0.005 x [^x^! x 5.38] = \$63 per trip

• Crew salary and cost (a) Flight crew

493 x 5.38 = \$2, 652 per trip for two crew (b) Cabin crew = 0 because there is no cabin crew

Trip-Cost Elements

• Landing fees = (x 5-38) = \$74 per trip

• Navigational charges = ^°1х2,о«ъ<о52^ x у94 x 5.33 = \$803 per trip

• Ground-handling charges = (100<8’1) x 5.38 = \$110per trip

• Airframe maintenance, material, and labor (a) airframe labor

350

= (°.°9 < 5 ■52 x 1 .°2 + 6 7 – (5.52 <102 + 75)

x 63 = (1.853) x 1.448 x 63 = \$169 per trip

(b) airframe material cost = (4-2+2-2x5C38 °-25)) x 7 x 5.38 = \$109 per trip where Cairframe = \$7 million

Total airframe maintenance (material + labor) = 910 + 109 = \$1,019 per trip

• Engine maintenance, material, and labor (a) engine labor = 0.21 x 63 x 1.018 x 0.89 x (1 + 1.72)0 4 = \$17.88 per hour

where T = 17.23 KN = 1.72 tons C1 = 1.27 – 0.2 x 3.202 = 1.018

C3 = 0.032 x 10 + 0.57 = 0.89

(b) engine material cost = 2.56 x (1 + 1.72)0 8 x 1.018 x (0.652 + 0.89) = 5.7 x 1.542 = \$8.79 per hour where C2 = 0.4 x (14/20)° + 0.4 = 0.652

Ci and C3 are the same as before.

(c) direct engine maintenance cost (labor + material)

= 2 x (17.88 + 8.79) x (g ^-q^) = \$308 per trip

• Fuel charges = 2, 233 x 0.3245 x 0.75 = \$544 per trip

The baseline Bizjet DOC is summarized in Table 16.15. Then, DOC per hour = 7,045/5.38 = \$1,309.50 per hour.

DOC per aircraft nm = 7°°° = \$3.52 per nm per trip

DOC per passenger mile per nm = 2 07°04×510 = \$0.352 per nm per passenger

DOC details of a midsize, high-subsonic transport aircraft are in Appendix C.

OC of the Variants in the Family

Large Variant: MTOM = 10,800 kg and 14 passengers Aircraft Price = \$9 million Ownership Cost Element = \$1,727 Crew Cost = \$3,047 Fuel Cost = \$625

Maintenance/Operational Charges = \$2,650 Total Operational Cost = \$8,049 Then, DOC per hour = \$8,049/5.38 = \$1,496.40 per hour The DOC per aircraft nm = 2°°° = \$4.025 per nm per trip

Table 16.15. Bizjet summary of DOC per trip (in U. S. dollars)

 Fixed cost elements Depreciation 807 Interest on Loan 665 Insurance Premium 63 Total Ownership Cost 1,535 Flight Crew 2,652 Cabin Crew 0 Total Fixed Cost Elements 4,187 Trip Cost Elements Fuel Charges 544 Navigational Charges 803 Landing Charges 74 Ground-handling Charges 110 Maintenance (Airframe) 1,019 Maintenance (Engine) 308 Total Trip Cost Elements 2,858 Total DOC \$7,045 per trip

The DOC per passenger mile per nm = 2 0004×914 = \$0.2875 per nm per passenger.

Smaller Variant: MTOM = 7,900 kg and six passengers Aircraft Price = \$6.2 million Ownership Cost Element = \$1,228 Crew Cost = \$2,201 Fuel Cost = \$451

Maintenance/Operational Charges = \$1,916 Total Operational Cost = \$5,796 Then, DOC per hour = \$5,796/5.38 = \$1,077.30 per hour.

The DOC per aircraft nm = |200 = \$2.898 per nm per trip.

The DOC per passenger mile per nm = 2 00796 6 = \$0.483 per nm per passenger.