# AD 87-10-06 R1: Rocker Arm Assembly

- Type: Airworthiness directive
- Status: Current
- Products: Lycoming Engines IO-360-B4, IVO-360-A1A, O-340-A1A, O-340-A2A, O-340-B1A, O-540-E4G5, VO-360-A1A, VO-360-A1B, VO-360-B1A, AEIO-320-D1B, AEIO-320-D2B, AEIO-320-E1A and 234 more
- Effective: September 1, 1989
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-6293
- Registered aircraft: 71,991 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2345033EEBFB865986256842006B4839.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/87-10-06-R1

## The airworthiness directive

87-10-06 R1 TEXTRON LYCOMING: Amendment 39-5604 as revised by Amendment 39-6293.

Applicability: Textron Lycoming (formerly AVCO Lycoming Textron) reciprocating engine series having model and serial numbers as listed herein.

O-320-A & E series engines with serial numbers L-50154-27A through L-50175-27A, L-50177-27 through L-50188-27A.

O-320-B & D series engines with serial numbers L-13971-39A, L-13972-39A, L-13975-39A, L-13976-39A, L-13980-39A, L-13983-39A through L-14235-39A, L-14242-39A, L-14243-39A, L-14249-39A through L-14415-39A, L-14421-39A, L-14428-39A.

IO-320 series engines with serial numbers L-5890-55A through L-5897-55A.

O-360 series engines with serial numbers L-31144-36A through L-31146-36A, L-31150-36A through L-31357-36A, L-31363-36A through L-31507-36A.

IO-360-B series engines with serial numbers L-24152-51A, L-24163-51A, L-24170-51A, L-24248-51A, L-24337-51A through L-24344-51A, L-24352-51A.

AEIO-360B series engines with serial numbers L-24168-51A, L-24195-51A, L-24337-51A through L-24344-51A, L-24357-51A.

The O-540 serial numbers that follow may or may not have the letter "A" as part of the suffix of the serial number on the engine dataplate.

O-540 series engines with serial numbers L-23946-40A, L-23949-40A through L-24059-40A, L-24061-40A.

IO-540-C4B5 engines with serial numbers L-22974-48A, L-22975-48A, L-23010-48A through L-23016-48A, L-23038-48A, L-23039-48A, L-23050-48A through L-23052-48A, L-23118-48A, L-23138-48A, L-23193-48A, L-23195-48A, L-23196-48A, L-23328-48A, L-23331-48A, L-23348-48A, L-23349-48A, L-23352-48A, L-23353-48A, L-23372-48A, L-23375-48A, L-23376-48A.

IO-540-C4D5D engines with serial numbers L-22920-48A, L-22923-48A, L-22924-48A, L-22958-48A through L-22963-48A, L-23022-48A through L-23027-48A, L-23079-48A through L-23082-48A, L-23088-48A, L-23095-48A through L-23099-48A, L-23148-48A through L-23153-48A, L-23165-48A through L-23180-48A, L-23237-48A through L-23239-48A, L-23264-48A through L-23273-48A, L-23307-48A through L-23316-48A, L-23358-48A, L-23359-48A.

IO-540-D4A5 engine with serial number L-23089-48.

IO-540-V4A5D engines with serial numbers L-22943-48A through L-22945-48A, L-22953-48A through L-22957-48A, L-23061-48A through L-23063-48A.

IO-540-W1A5D engines with serial numbers L-22964-48A, L-22965-48A, L-22976-48A through L-22979-48A, L-23020-48A, L-23021-48A, L-23033-48A, L-23034-48A, L-23036-48A, L-23040-48A through L-23042-48A, L-23056-48A, L-23057-48A, L-23067-48A, L-23074-48A, L-23090-48A through L-23094-48A, L-23139-48A, L-23154-48A, L-23181-48A, L-23192-48A, L-23197-48A through L-23199-48A, L-23223-48A, L-23326-48A, L-23327-48A, L-23346-48A, L-23347-48A.

IO-540-W3A5D engines with serial numbers L-22918-48A, L-22966-48A, L-22967-48A, L-23350-48A, L-23351-48A.

AEIO-540-D series engines with serial numbers L-22927-48A, L-22994-48A, L-22995-48A, L-23035-48A, L-23037-48A, L-23043-48A, L-23044-48A, L-23065-48A, L-23066-48A, L-23075-48A through L-23077-48A, L-23100-48A, L-23101-48A, L-23108-48A through L-23110-48A, L-23114-48A, L-23127-48A, L-23135-48A, L-23143-48A through L-23147-48A, L-23159-48A through L-23164-48A, L-23189-48A through L-23191-48A, L-23200-48A, L-23201-48A, L-23232-48A, L-23233-48A, L-23245-48A, L-23259-48A, L-23260-48A, L-23274-48A through L-23294-48A, L-23329-48A, L-23330-48A, L-23343-48A, L-23344-48A, L-23368-48A, L-23369-48A, L-23373-48A.

TIO-540-AA1AD engines with serial numbers L-8753-61A, L-8782-61A, L-8783-61A, L-8837-61A, L-8845-61A.

TIO-540-AB1AD engines with serial numbers L-8751-61A, L-8752-61A, L-8758-61A, L-8763-61A through L-8765-61A, L-8777-61A through L-8779-61A, L-8784-61A, L-8785-61A, L-8788-61A through L-8790-61A, L-8798-61A through L-8800-61A, L-8803-61A through L-8806-61A, L-8813-61A through L-8816-61A, L-8821-61A through L-8824-61A, L-8833-61A through L-8836-61A.

Also applies to any of the following parallel valve-type engines,regardless of serial number, that were remanufactured or overhauled between July 1, 1985, and October 8, 1986, inclusive, or that have had a P/N LW-18790 rocker arm assembly installed (if the assembly was shipped from Lycoming Textron, Williamsport Division) during this same time period:

Engine Models: O-320 series except O-320-H; IO-320 series; AIO-320 series; AEIO-320 series; LIO-320 series; O-340 series; O-360 series except O-360-E; IO-360-B, -E, -F series; AEIO-360-B, -H series; HO-360 series; HIO-360-B series; VO-360 series; IVO-360 series; O-540 series; IO-540-C, -D, -J, -N, -R, -T, -V, -W series; AEIO-540-D series; TIO-540-C, -E, -G, -H, -K, -AA, -AB series, LTIO-540-K.

Compliance: Required (1) within the next 25 hours in service after the effective date of this AD for all applicable engines, and (2) prior to installation, for all P/N LW-18790 rocker arm assemblies not installed in engines, unless already accomplished.

NOTE: Rocker arm assemblies complyingwith this AD are identified by a letter "B" per AVCO Lycoming Textron Service Bulletin (SB) No. 477A, page 4, paragraph 6. All new and remanufactured engines shipped from the AVCO Lycoming Textron Williamsport Division Factory, and all overhauled engines shipped from the AVCO Lycoming Textron Service Center at Montoursville, Pennsylvania, after October 8, 1986, are in compliance with this AD.

To prevent possible rocker arm failure and loss of engine power, inspect and rework or replace rocker arm assembly P/N LW-18790, as necessary, in accordance with Sections 1 through 9 of AVCO Lycoming Textron SB No. 477A, dated February 16, 1987.

Measure and deburr the rocker arm as follows:

  (1) Measure the wall thickness at the specified thinnest point (outer edge) within the indicated circumferential limits using a ball-type micrometer, measuring microscope, or other instrument capable of providing equivalent accuracy.

  (2) Deburr the oil drip hole to obtain .030 inch radiusat rocker arm wall surface.

  (3) If it is not possible to determine the wall thickness or the oil drip hole radius within sufficient accuracy to assure compliance with SB 477A requirements, replace rocker arm with a new or serviceable rocker arm.

NOTE: Textron Lycoming SB No. 477A, Supplement No. 1, dated October 12, 1988, changes the affected models in accordance with changes in this amendment, but doe not change the inspection or rework procedures.

Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.

Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, New York Aircraft Certification Office, ANE-170, Federal Aviation Administration, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581.

Upon submission of substantiating data by an owner or operator through an FAA Maintenance Inspector, the Manager of the New YorkAircraft Certification Office, Valley Stream, New York, may adjust the compliance time specified in this AD.

AVCO Lycoming Textron SB No. 477A, dated February 16, 1987, identified and described in this document, is incorporated herein and made a part hereof pursuant to 5 U.S.C. 552 (a)(1). All persons affected by this directive who have already received this document from the manufacturer may obtain copies upon request to Customer Support, AVCO Lycoming Textron, 652 Oliver Street, Williamsport, Pennsylvania 17701.

This document also may be examined at the Federal Aviation Administration, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, Massachusetts 01803, Room 311, Rules Docket Number 86-ANE-48, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays.

This AD, 87-10-06 R1, revises Amendment 39-5604 (52 FR 17749; May 12, 1987), AD 87-10-06, which became effective on May 13, 1987.

This amendment (39-6293, AD 87-10-06 R1) becomes effective on September 1, 1989.

## Affected data sheets (9) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E-286](https://openairdocs.org/tcds/E-286): Lycoming Engines; names 54 of 72 models: O-360-C1C, O-360-C1A, O-360-B1A, O-360-A1A, O-360-A1H6, O-360-A1G6, O-360-G1A6, O-360-A4N…
- [TCDS E-274](https://openairdocs.org/tcds/E-274): Lycoming Engines; names 52 of 60 models: O-320-D2G, O-320-E2G, O-320-D3G, O-320-C2B, O-320-E2B, O-320-E2C, O-320-D2H, O-320-B3B…
- [TCDS E-295](https://openairdocs.org/tcds/E-295): Lycoming Engines; names 46 of 47 models: O-540-L3C5D, O-540-J2B5D, O-540-J1B5D, O-540-B2C5, O-540-B1D5, O-540-G2A5, O-540-H2A5, O-540-H1B5D…
- [TCDS 1E12](https://openairdocs.org/tcds/1E12): Lycoming Engines; names 32 of 32 models: AEIO-320-E1B, AEIO-320-D2B, AIO-320-C1B, AIO-320-A1A, IO-320-B1C, IO-320-C1B, IO-320-F1A, LIO-320-B1A…
- [TCDS 1E10](https://openairdocs.org/tcds/1E10): Lycoming Engines; names 24 of 89 models: AEIO-360-B1G6, HIO-360-B1B, IO-360-B2F6, IO-360-B2E, IO-360-B1F, IO-360-B1C, AEIO-360-B1B, IO-360-F1A…
- [TCDS 1E4](https://openairdocs.org/tcds/1E4): Lycoming Engines; names 21 of 81 models: AEIO-540-D4B5, IO-540-W3A5D, IO-540-C1B5, IO-540-N1A5, IO-540-C4B5, AEIO-540-D4A5, IO-540-C4D5D, IO-540-T4A5D…
- [TCDS E14EA](https://openairdocs.org/tcds/E14EA): Lycoming Engines; names 8 of 40 models: TIO-540-G1A, TIO-540-C1A, TIO-540-AB1AD, TIO-540-H1A, LTIO-540-K1AD, TIO-540-AA1AD, TIO-540-K1AD, TIO-540-E1A
- [TCDS 1E1](https://openairdocs.org/tcds/1E1): Lycoming Engines; names 4 of 4 models: IVO-360-A1A, VO-360-A1A, VO-360-B1A, VO-360-A1B
- [TCDS E-277](https://openairdocs.org/tcds/E-277): Lycoming Engines; names 3 of 3 models: O-340-A2A, O-340-B1A, O-340-A1A

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 71,991 (0 by airframe model, 71,991 by engine model)
- Makers: Piper 31,456, Cessna 15,341, Mooney 3,778, Beech 1,661, Bellanca 1,474, Robinson Helicopter 1,312, Grumman American Avn. 1,220, Maule 792, American Champion 721, Aviat 570

Models with the most aircraft:

- [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series): 27,061 aircraft (engine model)
- [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series): 11,930 aircraft (engine model)
- [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series): 6,173 aircraft (engine model)
- [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series): 5,228 aircraft (engine model)
- [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series): 4,886 aircraft (engine model)
- [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series): 4,219 aircraft (engine model)
- [Lycoming IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series): 1,707 aircraft (engine model)
- [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series): 1,023 aircraft (engine model)
- [Lycoming IO-360-B4A](https://openairdocs.org/engine/lycoming-io-360-b4a): 985 aircraft (engine model)
- [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d): 968 aircraft (engine model)
- [Lycoming AEIO-360 series](https://openairdocs.org/engine/lycoming-aeio-360-series): 881 aircraft (engine model)
- [Lycoming O-360-A1A](https://openairdocs.org/engine/lycoming-o-360-a1a): 601 aircraft (engine model)
- [Lycoming AEIO-540 series](https://openairdocs.org/engine/lycoming-aeio-540-series): 433 aircraft (engine model)
- [Lycoming O-360-A4M](https://openairdocs.org/engine/lycoming-o-360-a4m): 418 aircraft (engine model)
- [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series): 336 aircraft (engine model)
- [Lycoming O-540-F1B5](https://openairdocs.org/engine/lycoming-o-540-f1b5): 299 aircraft (engine model)
- [Lycoming O-320-E2D](https://openairdocs.org/engine/lycoming-o-320-e2d): 258 aircraft (engine model)
- [Lycoming O-320 series](https://openairdocs.org/engine/lycoming-o-320-series): 256 aircraft (engine model)
- [Lycoming IO-540-D4A5](https://openairdocs.org/engine/lycoming-io-540-d4a5): 237 aircraft (engine model)
- [Lycoming IO-360 series](https://openairdocs.org/engine/lycoming-io-360-series): 217 aircraft (engine model)

All 202 models: https://openairdocs.org/ad/87-10-06-R1/models.md
Every aircraft: https://openairdocs.org/ad/87-10-06-R1/aircraft.md

Its text cites no advisory circulars or STCs.

## NTSB investigations that cite this AD (2)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB SEA94LA235](https://openairdocs.org/ntsb/SEA94LA235), Sep 7, 1994: Cessna 172M (N61838), Coolin, ID, substantial damage. Probable cause: THE FAILURE OF THE ENGINE MANUFACTURER TO PROPERLY REMANUFACTURE AND ADEQUATELY INSPECT THE NO. 1 ROCKER ARM PRIOR TO ITS INSTALLATION ON THE ENGINE. THIS RESULTED IN FATIGUE CRACKING OF THE ROCKER…
- [NTSB LAX87LA275](https://openairdocs.org/ntsb/LAX87LA275), Jul 20, 1987: Piper PA-28-161 (N91338), Milpitas, CA, substantial damage

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