Appendix 8 APPENDIX 8. PROGRAM IMPLEMENTATION EXAMPLES
The following are provided to assist the operator in understanding the timeline for when the program should be implemented. Two examples are given, one covers airplanes below 75 percent of the design service goal (DSG) on December 18, 2009, and the other is for airplanes beyond the DSG on December 18, 2009.
a. Airplane Below 75 Percent of the DSG on December 18, 2009. Operators should complete a survey at the first heavy maintenance check (time limit equivalent to a “D-check”) after the airplanes reach 75 percent of the DSG, and not to exceed the DSG.
Consider the following:
(1) Airplane Total Flight Cycles on December 18, 2009, – 55,000
(2) DSG = 75,000 Cycles, 75percent DSG – 56,250 Flight Cycles
(3) Time of last “D”-Check Equivalent – 53,000 Flight Cycles
(4) 8-Year “D”-Check Equivalent – 365 Days/Year, 4 cycles/day = 11,680 Flight Cycles
The survey would be performed after the airplane has reached 56,250 total flight cycles (75% DSG) and would be due before the airplane has accumulated 11,680 flight cycles (D- check equivalent) beyond the time of the last D-check (53,000 flight cycles). Therefore, the survey would be due before the airplane has reached 64,680 total flight cycles, but in any case would be required before the airplane has reached 75,000 total flight cycles (DSG).
b. Airplane Beyond the DSG on December 18, 2009. Operators complete a survey of these airplanes at or before the next heavy maintenance check (equivalent to a D-check) after December 20, 2010, not to exceed 6 years.
Consider the following:
(1) Airplane Total Flight Cycles on December 18, 2009, – 80,000
(2) DSG = 75,000 Cycles, 75percent DSG – 56,250 Flight Cycles
(3) Time of last “D”-Check Equivalent – 78,540 Flight Cycles, conducted in Jan 2009
(4) 8-Year “D”-Check Equivalent – 365 Days/Year, 4 cycles/day = 11,680 Flight Cycles
(5) Assume maximum total flight cycles accumulated by December 20, 2010, to be 81,460 (80,000 flight cycles on 12/18/2009 + 1,460 flight cycles/year).
Consider an airplane that has 80,000 total flight cycles as of December 18, 2009, and a DSG of 75,000 total flight cycles. The airplane is currently on an 8-year D-check equivalent and the last D-check was performed in January 2009 at 78,540 total flight cycles. The survey would need to be performed prior to the airplane accumulating 11,680 flight cycles (D-check equivalent) beyond the time of the last D-check (78,540 flight cycles) or 6 years,
whichever occurs first. Therefore, the survey would be due before the airplane has reached 90,220 total flight cycles or 6 years, whichever occurs first, based on the airplane utilization
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Appendix 8 of 4 cycles/day, a 365-day year, and a maximum total of 81,460 flight cycles as of December 20, 2010.
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Appendix 9
APPENDIX 9. LIST OF SIGNIFICANT ALTERATIONS THAT MAY
ADVERSELY AFFECT FATIGUE CRITICAL STRUCTURE
1. Passenger-to-freighter conversions (including addition of main deck cargo doors).
2. Gross weight increases (increased operating weights, increased zero fuel weights, increased landing weights, and increased maximum takeoff weights).
3. Installation of fuselage cutouts (passenger entry doors, emergency exit doors or crew escape hatches, fuselage access doors, and cabin window relocations).
4. Complete re-engine or pylon alterations.
5. Engine hush-kits.
6. Wing alterations such as installing winglets or changes in flight control settings (flap droop), and alteration of wing trailing edge structure.
7. Modified skin splices.
8. Antenna Installations.
9. Any alteration that affects several stringer or frame bays.
10. An alteration that covers structure requiring periodic inspection by the operator’s maintenance program.
11. An alteration that results in operational mission change that significantly changes the manufacturer’s load or stress spectrum (e.g., passenger-to-freighter conversion). Examples of this type of alteration may be an alteration that adds new structural splices, or increases the operational loads causing existing structure to become fatigue critical.
12. An alteration that changes areas of the fuselage which prevents external visual inspections (for example, the installation of a large external fuselage doubler that results in hiding details beneath it).
13. In general, attachment of interior monuments to fatigue critical structure. Interior monuments include large items of mass such as galleys, closets, and lavatories.
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