1400 North Hurstbourne Parkway 

louisville, KY 40223 

502.329.3000 Tel 

October 20, 2014 

Federal Aviation Administration 

C/0 U.S. Department of Transportation 

Docket Operations, M-30 

West Building Ground Floor 

Room W12-140 

1200 New Jersey Avenue SE 

Washington, DC 20590 

SUBJECT: Notice of Proposed Rule Making (NPRM) 2013-NM-136-AD 

Docket No. FAA-2014-0648; Directorate Identifier 2013-NM-136-AD 

To Whom It May Concern: 

The Federal Aviation Administration released the subject Notice of Proposed Rulemaking (NPRM) for 

comments on September 22, 2014, via Federal Register Volume 79, Number 183, pp. 56526-56532. The 

NPRM proposes to supersede Airworthiness Directive (AD) 2010-06-04 which requires repetitive 

inspections to detect cracks of the pylon side panels (upper section) at rib 8 in accordance with Airbus SB 

A300-54-6015, Revision 03. Since AD 2010-06-04 issuance, additional analysis has shown that reduced 

compliance times and repeat inspection intervals are needed to ensure the structural integrity of the 

inspected area. United Parcel Service Co. (UPS Airlines) has reviewed the referenced proposed rule and 

offers the follow·ing comments regarding use of Average Flight Time (AFT) methodology for the 

proposed mandatory action threshold and repetitive intervals. 

The proposed rule identifies compliance times for the inspection threshold and repeat intervals using the 

Average Flight Time (AFT) methodology. Review of prior FAA AD -:omments notes, including AD 98-

18-02, that the FAA does not concur with the AFT compliance time methodology as" ... such adjustments 

may not address the unsafe condition in a timely manner" and" ... they (AFT compliance times) do not fit 

into the AD tracking process for operators or for Principle Maintenan..:.e Inspectors (PMI's) attempting to 

ascertain compliance with AD's." UPS shares the FAA concern with using the AFT compliance 

methodology. 
Federal Aviation Administration 

October 20, 2014 

Page 2 of2 

Under the proposed thresholds for aircraft utilization equal to or less than 1.5 AFT value, the aircraft is 

flight cycle limited as the flight hour limit cannot be reached (reference Figure 1). When considering AFT 

values greater than 1.5, the aircraft is still flight cycle limited until an AFT value of2.16 is achieved. At a 

utilization ratio of 2.16 and greater, the aircraft is flight hour limited. Therefore, variable flight hour limits 

add an unnecessary complexity to the threshold table and subsequent inspection actions. 

Use of the complex AFT methodology combined with the lack of procedures for the AFT method usage 

(lifetime AFT value or recent operational period, how often is AFT re-calculated, etc.) provides an 

opportunity for tracking errors and places an undue burden on aircraft operators and the regulatory 

authority to monitor compliance. UPS believes a more consistent and simplified compliance requirement 

(i.e. defined threshold and repeat intervals) achieves the safety intent of this ruling, provides for timely 

detection of possible damage and eliminates continuous AFT monitoring that is necessary to comply with 

the inspection interval compliance requirements in the proposed rule. Refer to Table 1 for proposed 

inspection threshold and repeat inspection intervals for this proposed ruling based on Airbus SB A300-

54-60 15 data and use of the simplified threshold and repeat inspection interval approach. 

UPS acknowledges the need for the pylon side skin panel inspection detailed in Airbus SB A300-54-

60 15. UPS believes the proposed inspection threshold and repeat inspection intervals proposed in Table 1 

provides an equivalent level of safety and minimizes risks associated with the AFT compliance time 

methodology. Thank you for your time in considering these comments. If you have any questions 

regarding this response, please contact Mark Hilborn at 502-329-6020 or by e-mail at 

mhilbom@ups.com. 

Sincerely, 

UNITED PARCEL SERVICE CO. 

Edward M. Walton 

Director of Engineering 

EW:MRH:mm 

Attachment 

c: Ed Walton 

Dan Haddix 

Bruce Nord 
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FIGURE 1: NPRM 2013-NM-136-AD Inspection Threshold Determination using AFT 

Methodology 

NPRM 2013-NM-136-AD Conf 002 Post Mod Repeat Inspection 

6,500 

6,000 

5,500 

5,000 

4,500 

4,000 

3,000 

0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 

Average Flight Time (AFT) 

-Fit Cycles (AFT<= 1.5) -Fit Cycles (AFT> 1.5) 

-FC Limit (AFT<= 1.5) -FC Limit (AFT> 1.5) 

For Configuration 002 (PW powered aircraft) after incorporation of SB A300-54-6021 as a repair (crack 

found during inspection), the chart shows that the repeat inspection interval is flight cycle limited. The 

flight hour repeat inspection limits ( 5,600 FH for AFT <= 1.5 and 7,500 FH for AFT > 1.5), the aircraft is 

flight cycle limited. For example, at an AFT value of 1.5, the aircraft will accumulate 3, 733 flight cycles 

when accumulating 5,600 flight hours. At the AFT value of 1.5, the FH threshold values change to 7,500 

FH or 3,400 FC. Thus the aircraft is limited by the flight cycle value until the AFT value= 2.16. This is 

true for both Configuration 001 (GE powered aircraft) and Configuration 002 aircraft. 

Therefore, use of the AFT methodology does not provide any safety enhancement or timely detection of 

damage based on the aircraft utilization. 
I 

TABLE 1: NPRM 2013-NM-136-AD Proposed Inspection Threshold and Repeat Intervals 

Table 1 identifies threshold and repeat inspection intervals for aircraft with various repair I modification 

embodiment status and engine type installation. 

Inspection Effectivity Engine Type Threshold Repeat 

Interval Interval 

General Electric 

All aircraft with SB A300-54-6021 not (GE) CF6-80 

accomplished (pre mod 10431S20462) and Pratt & Whitney 4,200 FC 3,600 FC 

with no prior repairs. (PW) 4000 

Pratt & Whitney 

(PW)JT9D 

General Electric 9,300 FC after 8,200 FH 

(GE) CF6-80 repair 4,100 FC 

All aircraft with SB A300-54-6021 with SB accomplishment 

A300-54-6021 accomplished as a repair Pratt & Whitney 

(PW) 4000 . 9,300 FC after 

(crack found during inspection). repair 7,500 FH 

Pratt & Whitney accomplishment 3,700 FC 

(PW) JT9D 

General Electric 10,100 FC after 8,200 FH 

repair (GE) CF6-80 4,100 FC 

All aircraft with SB A300-54-6021 accomplishment 

accomplished as preventative mod (no Pratt & Whitney 

cracking found during inspection). (PW) 4000 10,100 FC after 7,500 FH 

repair 3,700 FC Pratt & Whitney accomplishment 

(PW) JT9D