AD 99-01-08

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AD Number:
99-01-08
Document Type:
AD Final Rules
Docket Number:
98-ANE-77-AD
Subject Heading:
Airworthiness Directives; Pratt & Whitney JT8D and JT3D Series Turbofan Engines
Subject:
Stage 7 through Stage 15 High-Pressure Compressor (HPC) Disks
Status:
Current
Citation:
Federal Register: December 31, 1998 (Volume 63, Number 251)
Citation Publish Date:
12/31/1998
Effective Date:
01/05/1999
Make:
Pratt & Whitney Division
Model:
JT3D-1 | JT3D-1-MC6 | JT3D-1-MC7 | JT3D-1A | JT3D-1A-MC6 | JT3D-1A-MC7 | JT3D-3 | JT3D-3B ...Show more
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39 [63 FR 72148 NO. 251 12/31/98]
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 99-01-08
CITATION:   [Federal Register: December 31, 1998 (Volume 63, Number 251)]

PAGE NUMBER:   [Page 72148]

DOCKET NUMBER:   98-ANE-77-AD

AMENDMENT:   39-10975

AD NUMBER:   99-01-08

SUBJECT HEADING:   Airworthiness Directives; Pratt & Whitney JT8D and JT3D Series Turbofan Engines

ACTION:   Final rule; request for comments.

SUMMARY:   This amendment adopts a new airworthiness directive (AD) that is applicable to Pratt & Whitney (PW) JT8D and JT3D series turbofan engines. This action requires operators to remove and replace with serviceable parts, certain stage 7 through stage 15 high-pressure compressor (HPC) disks identified by part number and serial number. This amendment is prompted by a report of an uncontained failure of a stage 8 HPC disk during a takeoff roll that resulted in damage to the airplane. The actions specified in this AD are intended to prevent the failure of a high-pressure compressor disk due to Cadmium embrittlement, resulting in uncontained engine failure and damage to the airplane.

Comments for inclusion in the Rules Docket must be received on or before March 1, 1999.

DATES:   Effective January 5, 1999.

ADDRESSES:   Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 98-ANE-77-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address:
"9-ad-engineprop@faa.gov". Comments sent via the Internet must contain the docket number in the subject line.

The service information referenced in this AD may be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-6600, fax (860) 565-4503. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:   Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-7175, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:   The Federal Aviation Administration (FAA) has received a report of an uncontained failure of a stage 8 high-pressure compressor (HPC) disk, part number (P/N) 787008, installed on a Pratt & Whitney (PW) JT8D-9 turbofan engine. The laboratory testing revealed that the disk failed as a result of Cadmium embrittlement. Nickel-Cadmium (NiCd) coatings are used on JT8D and JT3D steel disks to inhibit corrosion. The coating process consists of many steps, the most fundamental of which are the electrolytic deposition of a Nickel base layer followed eventually by the electrolytic deposition of a Cadmium layer. The part is then baked in an oven. During the bake cycle the Nickel layer diffuses into the Cadmium which creates an alloy with a higher melting temperature than pure Cadmium and immobilizes the Cadmium to prevent the liquid metal embrittlement of the steel part. The Cadmium rich outer layer acts as the corrosion inhibitor. The diffused Nickel acts to immobilize the Cadmium and prevent Cadmium embrittlement of the steel. If the Nickel plating is not applied with sufficient thickness during the NiCd plating process, the undiffused Cadmium can attack the grain boundaries of the base metal. Failure results when the disk is exposed to engine operating temperatures and stresses. Analysis of this and other Cadmium embrittlement failures indicates that a disk exposed to Cadmium embrittlement will likely fail within 500 hours time-in-service (TIS). Based on the risks associated with a process anomaly at the repair facility that plated the disk, the FAA has determined that action is required to remove a number of disks plated at that facility since February 1996. The disks most at risk are those disks which have accumulated less than 500 hours TIS since they were last plated. Disks which have accumulated more than 500 hours TIS since plating will not be recalled by this AD. The FAA has identified stage 7 through stage 15 HPC disks by P/N and serial number (S/N) that have been NiCd plated by the repair facility from February 1996 through October 1998. This condition, if not corrected, could result in the failure of a high-pressure compressor disk due to Cadmium embrittlement, resulting in uncontained engine failure and damage to the airplane.

Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to prevent the failure of a high-pressure compressor disk due to Cadmium embrittlement, resulting in uncontained engine failure and damage to the airplane. This AD requires removal and replacement of certain part-numbered and serial-numbered stage 7 through stage 15 HPC disks with serviceable parts.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-ANE-77-AD." The postcard will be date stamped and returned to the commenter.

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.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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:

REGULATORY TEXT:   99-01-08 Pratt & Whitney: Amendment 39-10975. Docket 98-ANE-77-AD.

Applicability: Pratt & Whitney (PW) JT8D and JT3D series turbofan engines, with stage 7 through stage 15 high-pressure compressor (HPC) disks installed, identified by part number (P/N) and serial number (S/N) specified in Appendix 1. These engines are installed on but not limited to the following aircraft: Boeing 707, 727, and 737 series airplanes and McDonnell Douglas DC-8, DC-9, and MD-80 series airplanes.

Appendix 1
Disk Part Number and Serial Number (Sorted By Disk Part Number)
Stage	Disk Part Number	Disk Serial Number
7	701407	7A7271
7	701507	4Z2030, 4Z2122, 8Z6454
7	766007	8B5265
7	774407	B207AA0307, B207AA0350, B207AA0379, B207AA0578, B207AA0643, BENCAH1353, BENCAH2320, BENCAH2327, BENCAH2851, BENCAH4091, BENCAJ8414, BENCAJ8440, BENCAK1631, BENCAK1684,BENCAK5135, BENCAK6623, BENCAK6643, BENCAK8115, H19093, H19026, H29904, J17128, J17407, J39120, J72011, J72132, K20050, K20167, K78491, L72139, M15364, M15368, M77985, M83784, M93463, N14127, N14190, N14213, N24114, N23978, N24091, N37879, N37919, N70390, N88161, N88195, N88335, N88342, N94974, N95036, P14716, P14741, P35486, P54563, P60347, P60394, P60446, P70328, P81247, P81253, P81392, P81399, P86295, P86311, R03089, R12413, R12418, R12549, R12557, R19365, R31290, R31411, R37414, R37520, R37554, R46834, R46893, R46918, R46943, R47019, R72171, R72257, S05566, S05610, S05659, S10014, S10050, S13885, S13910, S14048, S14063, S14088, S14173, S36633, S36810, S36857, S37128, S37149, S37168, S37187, S37312, S37367, S37389, S37420, S37469, S37498, T04409, T04526, T04566, T04615, T04632, T04898, T04899, T04988, T05055, T05106
7	5006007-01	B207AA0068, B207AA0693, BENCAH0061, BENCAH3134, BENCAJ8558, BENCAJ8594, BENCAL0749, BENCAL2650, R54586, R79450, S11202, S11206, S57118, S57216, S57519
7	5006007-02	BENCAK9643, BENCAK9690, BENCAK9697, BENCAK9705, BENCAK9723, BENCAL3657, BENCAL5478
7	774407	BENCAH0521, BENCAJ8454, R57626, T04885
8	738308	9B1363, H03990
8	748608	7A9608, 7B9489, 8B0397, B208AA0030, B208AA0045, B208AA0070, BENCAJ8185, G30014, G62624, G63907, H29599, H35085, H64390, H84992, H86520, J29857, J29958, J57418, J57426, J57469, J57532, J57660, J57663, J94763, J94815, M54646, M54770, M54821, M54843, N14562, N14765, N84308, N84314, N84317, N84319, N84373, N84418, P26025, P26136, P26153, P26171, P28471, P28530, P28534, P28564, P28596, P28607, P83853, P94736, P98927, R18995, R46153, R73850, S01136, S01153, S01185, S50692, S50748, S78016, S78066, S78128
8	787008	K51696, K52389, L61543, M76852, M77423, M77749, M77791, N33354, N33408, N33702, N33760, N89060, N89386, N90133, N90152
8	787008F	N89050
8	787208	B228AA0194, B228AA0343, B228AA0371, B228AA0540, B228AA0574, B228AA0605, BENCAH4505, BENCAH5428, BENCAH5435, BENCAJ5724, BENCAK0065, BENCAK0066, BENCAK6165, BENCAK6359, BENCAK8796, BENCAK9253, BENCAL1567, BENCAL1571, BENCAL1579, BENCAL1887, BENCAL3339 ,BENCAL5283, BENCAM0672, J47026, K12730, N06609, N89709, P43644, P43665, P43897, P43936, P43950, P43954, P44141, P44694, P45378, P45593, R23192, R23234, R23450, R23452, R23569, R23837, R24172, R24201, R24205, R24390, R24599, R24827, R91709, S07732, S39110, S39281, S39337, S39409, S39410, S39487, S39509, S39534, S39633, S39676, S39721, S39942, S39963, S39996, S40033, S40041
8	788608	H36177
8	788708	7A2254
8	789508	G51990
8	789608	J46995
8	792038	B228AA0331, B228AA0511, B228AA1005, BENCAJ8854, BENCAJ8871
8	796348	K53240
8	797938	BENCAL2605
8	5005808-01	B228AA0901, BENCAJ1138, BENCAJ8902, S70327
9	628209	5X8746
9	701509	8Z5256, 9A6145, H86825, J00245, J25666, J87515, J89031, K34309, K35061, K55559, K85824, L31209, L31751, L55770, M10469, M40027, M49712, M61566, M84762, M86342, M86842, M86844, N02758, N02994, N209AA0006, N209AA0080, N209AA0091, N209AA0094, N209AA0255, N209AA0339, N209AA0352, N209AA0561, N21068, N21507, N21508, N22475, N22570, N22591, N41297, N42662, N57120, N79874, N79893, N81317, N97653, NENCAH0017, NENCAH0187, NENCAH0192, NENCAH0222, NENCAH0269, NENCAH0280, NENCAH0337, NENCAH0422, NENCAH0445, NENCAH0451, NENCAH0593, NENCAH0737, NENCAH0757, NENCAH0913, NENCAH0920, NENCAH1014, NENCAH1227, NENCAH1357, NENCAH1430, P11360, P11370, P11443, P11450, P12878, P51572, P52444, P52971, P53248, P77028, P77207, P78457, P97645, P98143, P98661, P98961, P98991, R17442, R18113, R45676, R46466, R72941, R73009, R73013, R73420, R73464, R73467, R73804, R73934, S00689, S00741, S00777, S00798, S18975, S19201, S50490, S77602, S77616, S77651
9	739509	G79836
9	772509	H49185, K56788, P97497, R73983, S01209, S50832
9	798509	B209AA0539, BENCAH3770, BENCAJ9383, BENCAK9880, BENCAL0717, BENCAL0703, BENCAL2372, BENCAL6305
9	701509	BENCAH0448
9	701509N	R18236
9	772509	K23767
9	798509	BENCAJ9360, P53159
10	701410	7Z0800, 7Z0806
10	701810	0A0377, 3B8966, 3B9144, 9Z9847, A00862, H39339, H60642, R22292
10	701810G	G82663
10	770510	4B4921, G80187
10	772510	B210AA0014, B210AA0202, B210AA0273, B210AA0637, B210AA0640, B210AA0749, B210AA0752, B210AA0429, BENCAH0251, BENCAH1404, BENCAJ9735, BENCAJ9784, BENCAJ9868, BENCAK5318, BENCAK5762, BENCAK5946, BENCAK9105, BENCAL0388, BENCAL1598, BENCAL1601, BENCAL2427, BENCAL4455, BENCAL5993, H34395, H58784, J23708, J68609, J87953, J88767, K03190, K03586, K24796, K25271, K35625, K55848, K66100, K68068, K85468, L15000, L56873, L84428, L86007, M10049, M10613, M39974, M56263, M61659, M84606, M87097, N03907, N02538, N02778, N03133, N21767, N22275, N41185, N41208, N41484, N41613, N42094, N42143, N42187, N42838, N57150, N57830, N57862, N80227, N80661, N80671, N81136, N81150, N81454, N81456, P11024, P11818, P11869, P12016, P12811, P51804, P51873, P52670, P53019, P53213, P76639, P77620, P77862, P78050, P97278, P98630, R17507, R18502, R18520, R44856, R44861, R44864, R45159, R46345, R72614, R72630, R72884, R73138, R73408, R73612, R73617, R73862, S01349, S01364, S01365, S01406, S01463, S01486, S19301, S19305, S19487, S19630, S50981, S51203, S70220, S78451, S78492, S78780, T18947, T19138, T19153, T49020, BENCAJ9732, N81125, S70249
11	701411	2B3335, 6Y6265, 6Y7124, 9Y4723
11	701811	A03782, G33309, H24029, J28340
11	701811D	5A8129
11	772511	B211AA0058, B211AA0106, B211AA0119, B211AA0240, B211AA0621, B211AA0744, B211AA0944, B211AA1224, B211AA1227, BENCAH4040, BENCAK0466, BENCAK7376, BENCAK7377, BENCAK7378, BENCAK7391, BENCAK7432, BENCAK7436, BENCAK7449, BENCAK7493, BENCAK7517, BENCAL2882, BENCAL2903, BENCAL3047, BENCAL3107, J23871, J60159, J60844, J88645, K23851, K25421, K34786, K35678, K56219, K86641, L30533, L31909, L84584, L85406, LI4848, M39922, M40288, M49491, M61348, M73855, M86390, N21317, N02565, N02849, N03254, N03566, N03749, N03884, N21373, N21747, N22005, N22023, N22361, N22749, N41265, N41900, N42762, N56596, N57211, N57249, N57915, N98569, N98918, N99538, P10980, P11984, P12374, P12389, P12900, P51911, P52733, P53057, P66436, P77051, P77157, P77977, P78064, P78528, P78566, R05712, R18713, R29689, R29849, R29855, R29858, R29957, R30079, R30091, R30098, R30396, R30540, R30753, R30778, R31032, R44897, R45822, R46094, R46488, S03919, S03920, S04110, S04209, S04340, S04487, S04565, S04576, S04601, S04625, S80671, S80726, S80801, S80817, S80830, T22255, T22427, T22430, T22433, T22695, T22711, T23028, B211AA0681, N97343
11	772511H	S03892
11	772511M	B211AA0066, B211AA0584
12	414212HC	5L5355
12	701412	1Z5717, 5Y5915
12	701812	1Z7175, 3A3910, A02080, H62635, N28026
12	701812D	G93483
12	717312	2B3418, G15036, G29488, G63557
12	769312	1Z5153
12	772512	H34015, H77074, J24654, J38490, J59514, K02314, K24837, K55637, K55648, K86189, L15523, L30268, L30307, L31553, L56280, L56328, L84937, L86244, M86432, M10163, M10415, M10948, M11260, M11282, M40263, M48887, M49046, M49595, M61285, M61856, M61955, M84903, M86222, N02391, N02431, N02488, N03222, N03686, N22344, N22883, N41245, N41249, N41463, N57445, N57460, N58065, N58102, N58109, N58117, N80256, N81365, N97115, N97124, N97457, N98208, N98222, N99001, N99066, P11199, P12270, P12312, P51405, P51433, P51437, P52633, P53139, P53173, P77109, P77978, P78005, P78202, P97472, P98163, P98509, P98706, P98876, R17547, R18000, R18009, R18395, R18404, R19046, R19047, R45120, R45947, R46042, R46055, R73153, R73459, R73782, R74102, R74120, R74356, R74528, S01701, S01720, S01963, S02019, S51348, S51376, S51391, S51490, S51499, S51540, S51542, S78919, S78924
12	798512	B212AA0948, B212AA0032, B212AA0209, B212AA0234, B212AA0255, B212AA0276, B212AA0283, B212AA0436, B212AA0439, B212AA0442, B212AA0497, B212AA0739, B212AA0788, B212AA0808, B212AA0826, B212AA1042, BENCAH1745, BENCAH2182, BENCAJ9560, BENCAJ9619, BENCAJ9680, BENCAK8619, BENCAK9455, BENCAL0437, BENCAL0445, BENCAL0446, BENCAL0450, BENCAL2451, BENCAL2462, BENCAL5111, BENCAL6030, R46125, S94444, S94463, S94550, T19384, T28481, T28560,T28581, T43085
12	772512	N97437
12	772512G	S02004
12	798512	BENCAJ9509, BENCAL2313, BENCAL6575
13	701813	9B6665, G92924, H10764, H63434, H63596
13	701813E	H40915
13	762413	T02660
14	750414	H91643, H92945, N68876, P95479, T39660
15	750115	H530181
15	750415	J35404, S97819

Note 1: This airworthiness directive (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 (b) 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 the failure of a high-pressure compressor disk due to Cadmium embrittlement, resulting in uncontained engine failure and damage to the airplane, accomplish the following:

(a) Remove from service stage 7 through stage 15 high-pressure compressor (HPC) disks identified in Appendix 1 of this AD as follows:

(1) For disks with less than 250 hours time in service (TIS) since last NiCd plating, remove disk and replace with a serviceable part within 100 hours TIS after the effective date of this AD.

(2) For disks with greater than or equal to 250 hours and less than 500 hours TIS since last NiCd plating, remove disk and replace with a serviceable part within 150 hours TIS after the effective date of this AD.

(3) For disks with greater than or equal to 500 hours TIS since last NiCd plating no action is required.

(4) Disks removed from service in accordance with this AD are not eligible for installation in any engine.

(b) 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 requests 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.

(c) 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 record search requirements of this AD can be accomplished.

(d) This amendment becomes effective on January 5, 1999.

FOOTER: