AD 98-21-24

This amendment adopts a new airworthiness directive (AD), applicable to Pratt & Whitney JT8D series turbofan engines, that requires removal, visual inspection, eddy current inspection, repair or replacement of affected compressor disks. This amendment is prompted by reports of improper fixturing during the electrolytic cleaning process of certain compressor disks at a certified repair station, Avial or Greenwich Air Services, currently GE Engine Services Dallas LP, certificate number RA1R445K of Dallas, Texas, that can result in damage to the disks in the form of arc burns. The actions specified by this AD are intended to prevent compressor disk cracking from arc burns in tie rod holes, shielding holes, or pressure balance holes, which could lead to a fracture of a compressor disk, resulting in uncontained release of engine fragments, inflight engine shutdown, and airframe damage.

Final rule.

98-21-24 Pratt & Whitney: Amendment 39-10832. Docket 97-ANE-45-AD.
Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, -17AR, -209, -217, -217A, -217C, and -219 model turbofan engines which have a compressor disk installed identified by part number and serial number in Table 1 of this airworthiness directive (AD). These engines are installed on but not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9 and MD80 series aircraft.
Note 1: This AD applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent compressor disk cracking from arc burns in tie rod holes, shielding holes, or pressure balance holes, which could lead to a fracture of a compressor disk, resulting in uncontained release of engine fragments, inflight engine shutdown, and airframe damage, accomplish the following:
(a) Within 3,000 cycles in service (CIS) after the effective date of this AD, or at the next shop visit, whichever occurs first, not to exceed 10 years after the effective date of this AD, remove, visually inspect, eddy current inspect, and repair or replace with a serviceable part disks identified by part number (P/N) and serial number (S/N) in Table 1 of this AD in accordance withGE Engine Services - Dallas, LP, Engineering Bulletin (EB) JT8D-025, dated March 27, 1998.

TABLE 1

STAGE
P/N
S/N
3
745803
H13469, N48096, N48361, P77936, P77942, P78298, P98041, P98334, R18766, R18989, R19227,R73555, R74156
4
745704
2A3332, 2A4258, G51920, H04195, J46788, J76639, K11388, K11483, K12946, K52509, K53069, L60864, L61145
4
777704
B114AA0034, B114AA0178, B114AA0274, BBDUA14597, BBDUAH4675, BBDUAH7390, J77499, J94590, K43182, L81216, L81217, L81218, L81224, L81688, M40670, M44376, M44384, M53723, M53753, M53810, M53815, N30898, N30938, N30943, N30947, N30956, N53261, N53280, N53284, N53290, N53296, N53299, N53309, N53317, N53324, N53337, N53340, N53347, N53355, N53356, N53361, N53364, N53366, N53373, N53388, N53390, N53392, N53397, N53402, N53405, N53407, N53409, N53411, N53413, N53416, N53419, N53426, N53434, N53437, N53438, N53449, N63635, N63637, N63646, N63651, N63696, N63704, N63718, N63736, N63740, N63745, N63803, P50018, P50025, P50036, P50050, P50054, P50083, P63990, R21906, R21930, R21985, R21991, R41366, R42431, R56904, R56911, R56932, R56948, R75603, R75635, R75644, S28269, S28335, S28336, S65405, S65417, S87903, S91630, T00466, T48099, T48101, T48105
4
799504
K23796, L61578, L61597, L89794, M77214, N06109, N06248, N06731, N06908, N06911, N32484, N32493, N32514, N33627, N33880, N34238, N89280, N89817, N90599, N90812, N90849, P45299, P45435, R23598, R23753, R24022, R24310, R24543, S07095, S07147, S07164, S07250, S58162, S58237, T02774, T02897, T03020, T03027, T03038, T03047
7
701407
7Z5379
7
766007
G11181
7
774407
B207AA0057, B207AA0164, B207AA0224, B207AA0270, B207AA0546, B207AA0719, B207AA0757, B207AA0768, B207AA0775, B207AA0913, BENCAH1914, BENCAH4273, BENCAJ5690, BENCAK1601, BENCAK5082, BENCAK5701, BENCAK6044, BENCAK6586,G78791, H19147, H75592, J08985, J17315, J17370, J72117, J93428, J93669, K78068, K78149, K78378, L23953, L71885, L71922, L72170, L72261, M38646, M44626, M60192, M78767, M83783, M93487, M93549, N24007, N24131, N58891, N58905, N59040, N70414, N88273, N88281, N88306, N93477, N95003, P14688, P14851, P16547, P35320, P35374, P35475, P54474, P54594, P60383, P81375, P81382, P86353, R19478, R31305, R37450, R46879, R46934, R57593, R57744, R57769, R72169, R72236, R81458, R81507, R81527, R81612, R90895, S05652, S13843, S14099, S14103, S36805, S36885, S36896, S36994, S36995, S37166, S37554, T04613, T04687, T04739, T04806, T04812, T04814, T04837, T04843, T04885, T04903, T04960, T05000, T05108
7
5006007-02
BENCAK9696, BENCAK9900, BENCAL0760, BENCAL1937, BENCAL4577, BENCAL5766
7
5006007-01
AA0297, B207AA0069, B207AA0135, B207AA0155, B207AA0172, B207AA0177, B207AA0354, B207AA0355, B207AA0421, B207AA0493, B207AA0533, B207AA0571, B207AA0684, B207AA0756, B207AA0811, BENCAH3454, BENCAH4003, BENCAH4004, BENCAH4371, BENCAH4373, BENCAH4794, BENCAH4797, BENCAH5400, BENCAH5401, BENCAJ8559, BENCAJ8585, BENCAJ8614, BENCAJ8626, BENCAJ8656, BENCAJ9106, BENCAK5959, BENCAK5963, BENCAK9770, BENCAK9771, BENCAL2683, BENCAL3622, BENCAL3931, K20260, K20499, K20543, N09043, N65077, N65107, N65132, N93173, N93193, P23185, P23236, P49794, P49835, P92551, P92580, R12660, R12670, R12710, R35504, R35530, R36545, R43821, R54576, R54634, R79460, R79466, R92415, R92431, R92435, R92442, S11034, S11058, S11154, S11156, S11179, S11182, S11186, S11202, S11206, S56884, S56888, S56998, S57073, S57075, S57117, S57120, S57156, S57157, S57192, S57220, S57332, S57354, S57405, S57412, S57420, S57424, S57437, S57452, S57467, S57470, S57589
8
748608
B208AA0043, BENCAK1564, H50069, H64474, H64605, J57591, J94824, M54652, M54835, N14526, N84300, P-28517, P26161, P28493, P28504, P28505, P28511, P28542, P28614, P98885, S01079, S01090, S50742, S78049, S78056, S78100
8
787008
J76875, K12869, M77087, N06806, N32406, N34151, N89336, N89554, N90392, N90682
8
787028
N89693
8
787208
AA0676, B07691, B228AA0169, B228AA0242, B228AA0288, B228AA0389, B228AA0426, B228AA0537, B228AA0576, B228AA0638, B228AA0641, B228AA0746, B228AA0859, B228AA0866, B228AA0878, B228AA0905, B228AA1070, B228AA1117, BENCAH0302, BENCAH1584, BENCAH3448, BENCAJ5729, BENCAJ8175, BENCAJ8767, BENCAJ8773, BENCAJ8790, BENCAJ9142, BENCAK4678, BENCAK4771, BENCAK5470, BENCAK6156, BENCAK6162, BENCAK6398, BENCAK8259, BENCAK9252, BENCAK9261, BENCAL2604, BENCAL2642, BENCAL4344, BENCAL7699, BENCAL9217, J76954, K11762, K12737, K12765, L89874, M41582, M41586, M41918, M76995, M77005, M77119, N06396, N33501, N33769, N33774, N33776, N33784, N34183, N34207, N89068, N89079, N89082, N89087, N89089, N89404, N89409, N89699, N89702, N89708, N89895, N89898, N90251, N90344, N90990, P43853, P43872, P43891, P43956, P43986, P44338, P45405, R23233, R23836, R23873, R24174, R24227, R24677, R24739, R24816, R24824, R91601, R91825, R91870, R91947, R92114, R92308, S07578, S07629, S07758, S07768, S07775, S39269, S39468, S39513, S39638, S39655, S39663, S39753, S39822, S39837, S39951, S39973, S39995, S40027, S40038, S40077, S40079, S400958
789608
H03942, J21516
8
792038
B228AA0039, BENCAJ8836
8
797938
B228AA0487, B228AA1034, BENCAJ8910, BENCAL5921, N06290, N33267, N90703, N90970, S70436, T03512
8
5005008-01
T03421, B228AA0052, B228AA0287, B228AA0405, B228AA0490, B228AA0519, BENCAH1577, L60763, M77630, N06193, N32395, N32524, N33073, N33304, N33466, N89447, N89464, P44800, P45226, R24458, R91359, R91787, S07967, S70327, S70429, S70463, S70494, S70520, T03317, T03452, T03476, T03506, T03549
8
5006008-01
R24001
9
701509
5A1936, J89101, L56782, L85804, M09404, M73608, M84236, N02058, N02998, N209AA0242, N209AA0246, N209AA0323, N209AA0418, N209AA0634, N22582, N56942, N56952, N79878, N97637, N97707, N98354, N99323, NENCAH0592, NENCAH0697, NENCAH0883, NENCAH1173, NENCAH1422, NENCAH1432, P11303, P11463, P12707, P52176, P52596, P52608, P97654, P97704, P98673, R18109, R18342, R18385, R45763, R45850, R46297, R46394, R46403, R72835, R72839, R72846, R73002, R74484, S00704, S00765, S00824, S00886, S00909, S00910, S18837, S18941, S19027, S50340, S70059, S77627, S77671, S77784, S77809, T18893, T18909, T27458, T27587
9
739509
H17622
9
772509
K23758, K24989, K86136, L15428, M40393, M40397, N42380, N56529, N79955, N79970, N80784, N96815, N96816, N96904, N96905, N97800, N97806, N99352, N99353, N99362, N99367, N99368, N99376, P11398, P11407, P11411, P11414, P11419, P12231, P76976, P76987, P76990, P76992, P76994, R17787, S01222, S02183, S50825
9
798509
AA0579, B209AA0068, B209AA0086, B209AA0100, B209AA0103, B209AA0105, B209AA0185, B209AA0261, B209AA0304, B209AA0364, B209AA0420, B209AA0429, B209AA0434, B209AA0461, B209AA0518, B209AA0542, B209AA0551, B209AA0619, B209AA0632, B209AA0649, B209AA0707, BENCAH2176, BENCAJ6152, BENCAJ9319, BENCAJ9337, BENCAJ9348, BENCAJ9359, BENCAJ9366, BENCAK0166, BENCAK4404, BENCAK4409, BENCAL0725, BENCAL2575, BENCAL4022, BENCAL6238, N03324, N42399, N42401, N56700, N97809, N99501, P53159, P77576, R72583, R73591, R74285, S02121, S02165, S79341, S79364, S79409, S79414, S94376, S94384, S94391
10
770510
G80186
10
772510
B210AA0003, B210AA0024, B210AA0062, B210AA0128, B210AA0263, B210AA0339, B210AA0398, B210AA0520, B210AA0538, B210AA0549, B210AA0563, B210AA0619, B210AA0684, B210AA0727, B210AA0744, B210AA0785, B210AA0860, B210AA0862, B210AA0956, B210AA0984, B210AA1073, B210AA1081, B210AA1137, BENCAH1958, BENCAH2165, BENCAH2280, BENCAJ5741, BENCAJ9159, BENCAJ9705, BENCAJ9757, BENCAJ9767, BENCAJ9773, BENCAJ9805, BENCAK4597, BENCAK5154, BENCAK5350, BENCAK5735, BENCAK5773, BENCAK6465, BENCAK9082, BENCAK9123, BENCAK9429, BENCAK9434, BENCAL1600, BENCAL1635, BENCAL2434, BENCAL3279, BENCAL5558, BENCAL6141, BENCAL6373, H17769, H32904, H34713, H57950, H76378, K56398, K66132, K86040, L15008, L32061, L55910, L56859, L86006, M10588, M10987, M39587, M39591, M49011, M49358, M49359, M73918, M86490, N02251, N02274, N11091, N22833, N42134, N56280, N57181, N57382, N57418, N57437, N80225, N80703, N80716, N80718, N81110, N81114, N81474, N97025, N97067, N97527,N97553, N97574, N97591, N97832, N98539, N98750, N98764, N98768, N98798, P11004, P11017, P11029, P11039, P11087, P11094, P11101, P11562, P11575, P11834, P12009, P12612, P12615, P12645, P12648, P51452, P51454, P51833, P51883, P52238, P53116, P53207, P53327, P76886, P76891, P77070, P77161, P77180, P77423, P77618, P77663, P77668, P77744, P77752, P97017, P98117, P98258, P98840, R18022, R18124, R18611, R18665, R19275, R46329, R46679, R72606, R72615, R72617, R72874, R73345, R74396, S01267, S01277, S01369, S01501, S01631, S01680, S19280, S19293, S19294, S19298, S19328, S19440, S19447, S19458, S19467, S19486, S19512, S51089, S51144, S51176, S51210, S78237, S78294, S78298, S78318, S78439, S78464, S78511, S78623, S78642, S78724, T19014, T19091, T19152, T19169, T28070, T28091, T28136, T28138, T49026, T49044, T49055, T49068, T49089
11
701411
G29388, G43952
11
769611
H16901
11
772511
AA0065, B211AA0047, B211AA0157, B211AA0171, B211AA0263, B211AA0301, B211AA0349, B211AA0356, B211AA0517,B211AA0529, B211AA0599, B211AA0622, B211AA0624, B211AA0705, B211AA0798, B211AA0823, B211AA0945, B211AA1004, B211AA1107, B211AA1166, B211AA1212, B211AA1292, B211AA1360, BENCAH0264, BENCAH2171, BENCAH5424, BENCAJ8130, BENCAK0910, BENCAK7121, BENCAK7336, BENCAK7407, BENCAK7412, BENCAK7417, BENCAK7523, BENCAL2881, BENCAL2959, BENCAL3030, H58238, H99450, J24528, J68900, J88334, K24665, K35705, K85911, L15671, L30512, L84603, L84967, M11198, M11208, M40116, M49492, M49540, M49551, M61349, M61810, M61821, M61827, M73414, M86423, M86943, M87075, N02874, N03522, N21358, N22738, N41160, N41282, N41646, N41748, N42587, N42774, N56399, N56596, N57323, N57878, N57899, N57939, N57953, N80541, N80554, N80580, N81408, N93700, N96929, N96947, N96955, N97354, N97368, N97956, N97977, N98242, N98245, N98573, N98587, N98612, N98949, N98963, N98974, N98976, N98981, N98985, N99526, N99535, N99551, N99553, N99564, N99590, P03620, P11615, P11637, P11959, P11981, P12385, P12387, P12399, P12743, P12777, P12930,P51979, P52109, P52732, P52903, P52910, P76731, P76820, P76832, P76857, P77637, P77642, P97786, R05382, R05539, R05747, R29690, R29884, R30070, R30119, R30137, R30157, R30194, R30226, R30258, R30313, R30429, R30504, R30534, R30617, R30625, R30808, R30810, R30906, R30941, R30993, R31009, R31035, R31073, R31118, R46248, R46361, S03667, S03741, S03745, S03805, S04156, S04451, S04460, S04473, S04542, S04543, S04557, S04564, S04582, S04649, S80373, S80389, S80465, S80547, S80588, S80617, S80682, S80740, S80765, T22044, T22052, T22099, T22202, T22236, T22261, T22353, T22378, T22395, T22405, T22521, T22533, T22593, T22608, T22653, T22797, T22835, T22873, T22895, T22949, T23006
12
717312
2B1946, 3A7441
12
772512
B212AA0565, B212AA0864, H58261, H58448, J23046, J68527, J89283, K04097 K23952, K23992, K35819, K55628, K55951, K56079, K66470, K66500, K86442, K86447, L15502, L30899, L31589, L32003, L56276, L56294, L56303, L56308, L56886, L85095, L86236, M10233, M10966, M40081, M49574, M49665, M73392, M84838, N02466, N03990, N21261, N22069, N22894, N41128, N41249, N41717, N42236, N42871, N56325, N57451, N58072, N58127, N80601, N81044, N81173, N81187, N97079, N97083, N97109, N97384, N97438, N97455, N97457, N97893, N97916, N98152, N98162, N98654, N98657, N98680, N98691, N99016, N99025, N99049, N99057, N99094, N99125, P11154, P11179, P11183, P11193, P11252, P11678, P11699, P11877, P11879, P11909, P12244, P12277, P12493, P12519, P51414, P52139, P52409, P52520, P52871, P53141, P53351, P53396, P72298, P76702, P76921, P76931, P77096, P77294, P77338, P77695, P77796, P78510, P97315, R17703, R17746, R18201, R18319, R18589, R19042, R45067, R45829, R46100, R46108, R46121, R46707, R52615, R72811, R73024, R73783, R74357, S01858, S01860, S01914, S01923, S01949, S01969, S01971, S01980, S01994, S02002, S02007, S19593, S19644, S19843, S51370, S51437, S51514, S51519, S51560, S51571, S78825, S78841
12
798512
B212AA0009, B212AA0045, B212AA0051, B212AA0060, B212AA0073, B212AA0077, B212AA0082, B212AA0142, B212AA0155, B212AA0290, B212AA0293, B212AA0361, B212AA0428, B212AA0586, B212AA0618, B212AA0647, B212AA0735, B212AA0747, B212AA0942, B212AA0974, B212AA1031, B212AA1062, B212AA1098, B212AA1173, BENCAH1931, BENCAH4104, BENCAJ4925, BENCAJ6158, BENCAJ7821, BENCAJ8115, BENCAJ9478, BENCAJ9497, BENCAJ9503, BENCAJ9530, BENCAJ9617, BENCAJ9673, BENCAK0455, BENCAK2377, BENCAK4552, BENCAK5787, BENCAK8605, BENCAK9227, BENCAL1655, BENCAL2487, BENCAL4173, BENCAL6328, BENCAL6602, M86993, N42703, N42708, N57617, N57629, N80087, N80088, N98138, N99136, N99144, P53305, P76909, P76916, P77722, P78317, R17334, R46556, R46562, R73201, R74214, S02217, S02254, S51853, S79575, S94530, S94534, S94538, S94539, S94569, S94579, S94590, S94615, T19187, T19213, T19220, T19242, T19277, T19292, T19314, T28638, T43059

(b) For the purpose of this AD, a shop visit is defined as an engine removal, where engine maintenance entails separation of pairs of major mating engine flanges or the removal of a disk, hub, or spool regardless of other planned maintenance except where the maintenance is being done in lieu of performing the maintenance on wing.
(c) The accomplishment of the inspections and repairs specified in this AD must be performed at GE Engine Services - Dallas, LP., certificate number RA1R445K of Dallas, Texas. Operators wishing to use another facility to perform the required inspections and repairs must apply for an alternative method of compliance in accordance with paragraph (e) of this AD.
(d) Report the following information on a monthly basis to the Manager of the Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 01803-5299; fax (781) 238-7199, Internet: Mark.C.Fulmer@faa.dot.gov. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056:
(1) S/N of disks inspected in accordance with paragraph (a) of this AD
(2) S/N of disks found with arc burns and approximate size of the arc burn.
(3) S/N of disks repaired in accordance with paragraph (a) of this AD.
(4) Hours and CIS since last shop visit and total hours and CIS of disks inspected in accordance with paragraph (a) of this AD.
(5) Report to the Manager of the Engine Certification Office, within two business days of finding one of the following conditions as a result of inspecting a disk in accordance with paragraph (a) of this AD:
(i) A crack depth of more than 5 mils.
(ii) More than 2 tie rod holes with cracks.
(iii) Arc burn depth beyond 9 mils.
(e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(f) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the inspection requirements of this AD can be accomplished.
(g) The actions required by this AD shall be done in accordance with the following GE Engine Services - Dallas, LP, EB:

Document No
Pages
Date
JT8D-025
1-3
March 27, 1998.
Total Pages: 3.

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from GE Engine Services - Dallas LP, 9311 Reeves St., Dallas, TX 75235-2095. Copies may be inspected at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA; orat the Office of the Federal Register, 800 North Capitol Street NW., suite 700, Washington, DC.
(h) This amendment becomes effective on November 16, 1998.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Pratt & Whitney (PW) JT8D series turbofan engines was published in the Federal Register on January 22,1998 (63 FR 3483). That action proposed to require, at the next shop visit after the effective date of the AD, a one-time visual and eddy current inspection of compressor disks to detect arc burn damage and if appropriate, repair of the damaged area.
After publication of that notice of proposed rulemaking (NPRM), the FAA received a comment from the manufacturer stating that a drawdown schedule for removal of affected disks should be added to the proposed rule to maintain an acceptable level of safety, instead of requiring the inspection at the next shop visit. The FAA concurred and added a drawdown schedule of 3,000 cycles in service (CIS) after the effective date of this AD, or the next shop visit, whicheveroccurs first, to the supplemental NPRM (SNPRM), published May 15, 1998 (63 FR 27002), which reopened the comment period.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received in response to both the original NPRM published in January 1998 and the subsequent SNPRM published in May 1998.
One commenter to the original NPRM states that maintenance done in a shop that could otherwise been done on-wing should be excluded from the shop visit definition of this AD. The FAA concurs. This change to the definition of the term "shop visit" was incorporated into the SNPRM.
One commenter states that the final rule should reassess the drawdown interval based on the number of disks inspected to date, and require appropriate inspections to occur based on intervals using cycles since potentially arc-burned, instead of cycles from effective date of the AD. The FAA does not concur. The current drawdown interval manages the risks on a fleet-wide basis. While the FAA recognizes that some operators may not exactly fit this model, the FAA has determined that using a fleet-wide basis is an analytically sound approach to manage this unsafe condition. Those operators who wish to develop inspection intervals to fit their operation based on cycles since potentially arc-burned, may do so under the provisions of paragraph (e) of this AD.
One commenter notes that disk, P/N 774407, S/N P60383 is listed twice in table. The FAA concurs and has removed the additional entry as a typographical error.
One commenter requests that clarification of the one-time inspection be included in the AD. The FAA does not concur. The required visual and eddy current inspections must be performed once within 3,000 cycles in service after the effective date of the AD, or at the next shop visit, whichever occurs first, not to exceed 10 years from the effective date of the AD. There is no need for a terminating action as there are no repetitive inspection requirements. The FAA will monitor the inspection results and determine if additional rulemaking action is warranted.
Two commenters state that the repair procedures should be available to the entire industry for incorporation into their approved procedures, rather than only allowing GE Engine Services - Dallas, LP., certificate number RA1R445K of Dallas, Texas. The commenters believe that other facilities are just as qualified to perform the inspections and repairs. The FAA does not concur. The inspection criteria and procedures for finding disk arc burns use a unique and novel technique and therefore operators who want to use an alternate source for compliance to the AD must do so under the provisions of paragraph (e) of the AD.
One commenter believes that manuals should be updated with precautions against using improper fixturing. The FAA does not concur. The FAA has reviewed the engine manuals and determined that the appropriate precautions are already included in the engine manuals.
One commenter states that the economic analysis is incorrect because of the availability of required tooling. The FAA does not concur as these costs do not directly stem from the AD's required actions. The indirect costs associated with performing the maintenance actions required by this AD are not directly related to this proposed rule, and, therefore, are not addressed in the economic analysis for this rule. A full cost analysis for each AD, including such indirect costs, is not necessary since the FAA has already performed a cost benefit analysis when adopting the part 33 (14 CFR part 33) airworthiness requirements to which these engines were originally certificated. A finding that an AD is warranted means that the original design no longer achieves the level of safety specified by those airworthiness requirements, and that other required actions are necessary, as in this case, inspecting and repairing as necessary or removing high pressure compressor disks. Because the original level of safety was already determined to be cost beneficial, these additional requirements needed to return the engine to that level of safety do not add any additional regulatory burden, and, therefore, a full cost analysis would be redundant and unnecessary.
One commenter states that GE Engine Services should be responsible for all costs incurred by operators. Financial responsibility is beyond the scope of this AD; therefore the FAA has no position relative to this comment.
Six commenters state that they have no objection to the rule as proposed.
In addition, the FAA has made an editorial change to paragraph (a) in order to clarify when the inspection requirements of this AD are to be performed. The last sentence is deleted from paragraph (a) and the requirement that affected engines be inspected no later than 10 years from the effective date of the AD added to the first part of the first sentence.
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
There are a total of 1,388 compressor disks exposed to improper fixturing during the electrolytic cleaning process. The FAA estimates that 1,054 of these disks currently remain in service in the worldwide fleet, which represents approximately 210 engines. The FAA also estimates that 840 of the disks affected by the AD are installed in engines installed on aircraft of U.S. registry. It will take approximately 30 work hours to accomplish the required actions per disk, and that the average labor rate is $60 per work hour. Required parts would cost approximately $23 per disk. Based on these figures, the total cost impact of the ADon U.S. operators is estimated to be $1,531,320.
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the RulesDocket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." List of Subjects in 14 CFR Part 39
Air Transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: