# AD 56-06-02: Cylinder Flange Attaching Stud

- Type: Airworthiness directive
- Status: Current
- Products: Pratt & Whitney Division Double Wasp CA15, Double Wasp CA17, Double Wasp CA18, Double Wasp CA19, Double Wasp CA3, Double Wasp CA5, Double Wasp CB16, Double Wasp CB17, Double Wasp CB3, Double Wasp CB4, Double Wasp R2800-97, Hornet A and 106 more
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Registered aircraft: 22 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FE83F7221B9305528625684F005C4868.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/56-06-02

## The airworthiness directive

56-06-02 PRATT & WHITNEY: Applies to All Models Engines.

Compliance required as indicated.

As a result of engine fire reported due to cylinder failure as a result of stud failures, the following must be accomplished to reduce cylinder and stud failures:

A. If a cylinder flange attaching stud fails during engine operation, the adjacent studs may be subjected to severe overstress. The same is true if an attaching nut becomes loosened to the extent that there is clearance between the nut and the cylinder flange. If more than two adjacent studs have broken, or the nuts have become loose, there is a probability that the cylinder flange has been overstressed.

B. If, during line inspection or at engine teardown prior to overhaul, a nut is found to be loose or there has been failure of a stud, replace that stud and the two adjacent studs.

C. If more than two adjacent studs have failed or if more than two adjacent nuts are known to have been loose during engine operation, the cylinder should be scraped or rebarreled and all the studs on the cylinder mounting pad replaced.

D. If only two adjacent studs have failed or two adjacent nuts have been found loose, the cylinder should be replaced, but it need not be scrapped provided that the nuts adjacent to the failed studs or loose nuts are found to be at least to minimum torque and that the cylinder flange has not become distorted more than 0.003 inch; also, that the flange and area above the flange are magnafluxed and show no crack indicators. If the bottom of the cylinder flange is not perfectly flat, but is not distorted more than 0.003 inch, it should be lapped flat before reinstallation. Before a replacement cylinder is installed, the crankcase studs immediately adjacent to the two broken or loose ones should be replaced.

E. During cylinder installation, securely tighten the cylinder flange attaching nuts.

(P&W Service Bulletin No. 1000 describes approved methods and torques.)(This subject is also covered in P&W Alert Bulletin No. 42 entitled "Cylinder Attachment Inspection and Maintenance".)

## Affected data sheets (35) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 1E8](https://openairdocs.org/tcds/1E8): Pratt & Whitney Division; names 11 of 11 models: JT3D-3, JT3D-3C, JT3D-1A-MC7, JT3D-1-MC6, JT3D-7, JT3D-1-MC7, JT3D-1A, JT3D-3B…
- [TCDS ATC 28 Pratt & Whitney](https://openairdocs.org/tcds/ATC%2028%20Pratt%20%26%20Whitney): Pratt & Whitney Division; names 9 of 9 models: Hornet SB-1, Hornet S2B1, Hornet S1B1, Hornet B, Hornet S1B1-G, Hornet B1-G, Hornet S3B1, Hornet B1…
- [TCDS E-230](https://openairdocs.org/tcds/E-230): Pratt & Whitney Division; names 8 of 8 models: Twin Wasp D-3, Twin Wasp D-7, Twin Wasp 2SD1-G, Twin Wasp D-4, Twin Wasp 2SD-G, Twin Wasp D-14, Twin Wasp 2SD13-G, Twin Wasp D-5
- [TCDS E-123](https://openairdocs.org/tcds/E-123): Pratt & Whitney Division; names 7 of 7 models: Wasp Jr. T1B3, Wasp Jr. B-4, Wasp Jr. SB-3, Wasp Jr. T1B2, Wasp Jr. SB, Wasp Jr. SB-2, Wasp Jr. B-5
- [TCDS E-231](https://openairdocs.org/tcds/E-231): Pratt & Whitney Division; names 7 of 7 models: Double Wasp CA5, Double Wasp CA15, Double Wasp CA17, Double Wasp R2800-97, Double Wasp CA19, Double Wasp CA18, Double Wasp CA3
- [TCDS E-247](https://openairdocs.org/tcds/E-247): Pratt & Whitney Division; names 7 of 7 models: Wasp Major B6, Wasp Major B7, Wasp Major CB2, Wasp Major B13, Wasp Major TSB3-G, Wasp Major B5, Wasp Major B14
- [TCDS E-129](https://openairdocs.org/tcds/E-129): Pratt & Whitney Division; names 6 of 6 models: Wasp S1H1, Wasp R-1340-61, Wasp S1H4, Wasp S3H2, Wasp S1H1-G, Wasp S1H2
- [TCDS E-186](https://openairdocs.org/tcds/E-186): Pratt & Whitney Division; names 6 of 6 models: Twin Wasp S1C-G, Twin Wasp S3C4-G, Twin Wasp SC-G, Twin Wasp S1C3-G, Twin Wasp SC3-G, Twin Wasp S4C4-G
- [TCDS E-291](https://openairdocs.org/tcds/E-291): Pratt & Whitney Division; names 6 of 6 models: JT4A-11, JT4A-3, JT4A-9, JT4A-10, JT4A-5, JT4A-12
- [TCDS ATC 14](https://openairdocs.org/tcds/ATC%2014): Pratt & Whitney Division; names 5 of 5 models: Wasp A, Wasp C, Wasp CD, Wasp B, Wasp C1
- [TCDS 1E9](https://openairdocs.org/tcds/1E9): Erickson Incorporated DBA Erickson Air-Crane; names 4 of 4 models: JT12A-6A, JT12A-6, JT12A-8, J60-P-5B
- [TCDS ATC 15](https://openairdocs.org/tcds/ATC%2015): Pratt & Whitney Division; names 4 of 4 models: Hornet A-1, Hornet A-3, Hornet A, Hornet A-2
- [TCDS E-264](https://openairdocs.org/tcds/E-264): Pratt & Whitney Division; names 4 of 4 models: Double Wasp CB16, Double Wasp CB17, Double Wasp CB3, Double Wasp CB4
- [TCDS E-290](https://openairdocs.org/tcds/E-290): Pratt & Whitney Division; names 4 of 4 models: JT3C-7, JT3C-12, JT3C-6, JT3C-4
- [TCDS ATC 90](https://openairdocs.org/tcds/ATC%2090): Pratt & Whitney Division; names 3 of 3 models: Wasp S1D1-G, Wasp TD1, Wasp S1D1
- [TCDS TC 85](https://openairdocs.org/tcds/TC%2085): Pratt & Whitney Division; names 3 of 3 models: Wasp Jr. TB, Wasp Jr. TB-2, Wasp Jr. T3A
- [TCDS ATC 158](https://openairdocs.org/tcds/ATC%20158): Pratt & Whitney Division; names 2 of 2 models: Twin Wasp SB3-G, Twin Wasp SB-G
- [TCDS ATC 193](https://openairdocs.org/tcds/ATC%20193): Pratt & Whitney Division; names 2 of 2 models: Hornet S1E3-G, Hornet S1E2-G
- [TCDS ATC 58 Pratt & Whitney](https://openairdocs.org/tcds/ATC%2058%20Pratt%20%26%20Whitney): Pratt & Whitney Division; names 2 of 2 models: Wasp SC-1, Wasp SC
- [TCDS E-142](https://openairdocs.org/tcds/E-142): Pratt & Whitney Division; names 2 of 2 models: Wasp S3H1-G, Wasp R-1340-59
- [TCDS ATC 128](https://openairdocs.org/tcds/ATC%20128): Pratt & Whitney Division; names 1 of 1 models: Wasp S3D1
- [TCDS ATC 136 (Pratt & Whitney)](https://openairdocs.org/tcds/ATC%20136%20(Pratt%20%26%20Whitney)): Pratt & Whitney Division; names 1 of 1 models: Hornet S1E-G
- [TCDS ATC 144 Pratt & Whitney](https://openairdocs.org/tcds/ATC%20144%20Pratt%20%26%20Whitney): Pratt & Whitney Division; names 1 of 1 models: Hornet S2E-G
- [TCDS ATC 145 (Pratt & Whitney)](https://openairdocs.org/tcds/ATC%20145%20(Pratt%20%26%20Whitney)): Pratt & Whitney Division; names 1 of 1 models: Wasp T2D1
- [TCDS ATC 39](https://openairdocs.org/tcds/ATC%2039): Pratt & Whitney Division; names 1 of 1 models: Wasp Jr. A
- [TCDS ATC 91](https://openairdocs.org/tcds/ATC%2091): Pratt & Whitney Division; names 1 of 1 models: Wasp T1D1
- [TCDS E-143](https://openairdocs.org/tcds/E-143): Pratt & Whitney Division; names 1 of 1 models: Wasp S3H1
- [TCDS E-257](https://openairdocs.org/tcds/E-257): Pratt & Whitney Division; names 1 of 1 models: Twin Wasp E1
- [TCDS E3EA](https://openairdocs.org/tcds/E3EA): Pratt & Whitney Division; names 1 of 3 models: JT3D-5A
- [TCDS TC 113](https://openairdocs.org/tcds/TC%20113): Pratt & Whitney Division; names 1 of 1 models: Wasp Jr. T1B
- [TCDS TC 5E-1](https://openairdocs.org/tcds/TC%205E-1): Pratt & Whitney Division; names 1 of 1 models: Military R-985 Series
- [TCDS TC 5E-2](https://openairdocs.org/tcds/TC%205E-2): Pratt & Whitney Division; names 1 of 1 models: Military R-1340 Series
- [TCDS TC 5E-4](https://openairdocs.org/tcds/TC%205E-4): Pratt & Whitney Division; names 1 of 1 models: Military R-1830 Series
- [TCDS TC 5E-5](https://openairdocs.org/tcds/TC%205E-5): Pratt & Whitney Division; names 1 of 1 models: Military R-2000 Series
- [TCDS TC 5E-8](https://openairdocs.org/tcds/TC%205E-8): Pratt & Whitney Division; names 1 of 1 models: Military R-2800 Series

## 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: 22 (0 by airframe model, 22 by engine model)
- Makers: North American 8, Rockwell International 5, Aerovodochody 3, Boeing 3, Mcdonnell Douglas 2, Aero Vodochody 1

Models with the most aircraft:

- [Pratt & Whitney JT12A-8](https://openairdocs.org/engine/pratt-whitney-jt12a-8): 12 aircraft (engine model)
- [Pratt & Whitney JT3D-3B](https://openairdocs.org/engine/pratt-whitney-jt3d-3b): 3 aircraft (engine model)
- [Pratt & Whitney JT12A series](https://openairdocs.org/engine/pratt-whitney-jt12a-series): 3 aircraft (engine model)
- [Pratt & Whitney JT12A-6](https://openairdocs.org/engine/pratt-whitney-jt12a-6): 2 aircraft (engine model)
- [Pratt & Whitney JT3D series](https://openairdocs.org/engine/pratt-whitney-jt3d-series): 2 aircraft (engine model)

All 5 models: https://openairdocs.org/ad/56-06-02/models.md
Every aircraft: https://openairdocs.org/ad/56-06-02/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, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB WPR16LA082](https://openairdocs.org/ntsb/WPR16LA082), Mar 12, 2016: Grumman G164 (N6894Q), Juliaetta, ID, substantial damage. Probable cause: A partial loss of engine power due to a crack in the No. 2 cylinder.
- [NTSB CEN15LA330](https://openairdocs.org/ntsb/CEN15LA330), Jul 31, 2015: Grumman G-164A (N963X), Emmett, KS, substantial damage. Probable cause: The engine failure due to several loose, damaged cylinder stud nuts and hold-down bolts. Contributing to the accident was maintenance personnel’s failure to detect that the cylinder nuts and…

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