Airworthiness Directive · Amendment 39-19317 · Turbine engine reduction gear
Honeywell International Inc. Turboprop and Turboshaft Engines
This AD applies to Honeywell International Inc. (Honeywell) TPE331-1, -2, -2UA, -3U, -3UW, -5, -5B, -6, -6A, -8, -10, -10AV, -10N, -10P, -10R, -10T, -10U, -10UA, -10UF, -10UR model turboprop and TSE331-3U turboshaft engines with hydraulic torque sensor gear assemblies, part numbers (P/Ns) 3101726-1, -2, or -3, installed.
We are adopting a new airworthiness directive (AD) for certain Honeywell International Inc. (Honeywell) TPE331 turboprop and TSE331 turboshaft engines. This AD was prompted by recent reports of failures of the direct drive fuel control gears and bearings in the hydraulic torque sensor gear assembly, part number (P/N) 3101726-3. This AD requires initial and repetitive engine oil filter sampling and analysis of the affected engines and inspections of certain hydraulic torque sensor gear assemblies. We are issuing this AD to address the unsafe condition on these products.
(1) Obtain an initial engine oil filter sample of the affected engines within 150 hours time in service after the effective date of this AD. You can find guidance for obtaining oil filter samples in Honeywell's engine training manuals; for example, see the TPE331 Line Maintenance Training Manual.
(2) Submit the engine oil filter sample within 3 days of sampling to an ISO/IEC 17025-accredited laboratory capable of performing analysis using ASTM D5185, Standard Test Method for Multielement Determination of Used and Unused Lubricating Oils and Base Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). You can find a list of Honeywell-authorized laboratories capable of performing this analysis in paragraph 1.D.(10) of Honeywell Service Information Letter (SIL) P331-97, Revision 11, dated July 23, 2008.
(3) Perform an oil filter analysis for wear metals and evaluate filter contents using paragraphs 1.D.(4) and (5) of Honeywell SIL P331-97, Revision 11, dated July 23, 2008. Guidelines for interpreting analysis results can be found in paragraph (8) of Honeywell SIL P331-97.
(4) For those engines where the oil filter analysis indicates the need for an inspection or resample, as specified in Figures 1, 2 or 3 of the Honeywell SIL P331-97, Revision 11, dated July 23, 2008, accomplish the following:
(i) If Figures 1, 2, or 3 indicate an inspection is required, within 5 days after receiving notification from the laboratory that performed the analysis, inspect the torque sensor gear assembly using paragraph (g)(4)(iii) of this AD.
(ii) If Figures 1, 2, or 3 indicate a resample is required, perform a repeat oil filter sample and analysis, within 25 hours time in service after receiving notification from the laboratory that performs the analysis to evaluate for wear metals in accordance with paragraphs (g)(1), (2) and (3) of this AD.
(A) If the resample indicates a second resample or inspection is required, within 5 days after receiving notification from the laboratory that performed the analysis, inspect the hydraulic torque sensor gear assembly using paragraph (g)(4)(iii) of this AD.
(B) Reserved.
(iii) Inspect the hydraulic torque sensor gear assembly using the following steps:
(A) Remove bearings, P/Ns 358893-1, 3103035-1, 3103585-1 or 70100168-1, from the assembled spur gear and fuel control drive gearshaft and inspect or replace. Guidance for performing the inspection can be found in Section 70-00-00, Standard Practices of the applicable TPE331 engine maintenance manual. For example, see paragraph 5., “Bearing Inspection,” on pages 11-12 of Honeywell Maintenance Manual 70-00-00, TPE331-10 (Report No. 72-00-27), dated February 29, 2000.
(B) Visually inspect the gearshaft teeth for scoring, pitting, chipping, metal deposits or corner breakage. Visual defects on gear teeth are acceptable if defects cannot be felt using a 0.031 inch diameter stylus. No corner breakage is allowed.
(5) Thereafter, repeat the steps identified in paragraphs (g)(1) through (4) of this AD every additional 150 hours time in service after last oil filter sampling.
(6) For any hydraulic torque sensor gear assembly that fails the inspection required by paragraph (g) of this AD, remove the affected hydraulic torque sensor gear assembly and, before further flight, replace with a part eligible for installation.
After the effective date of this AD, do not use the Honeywell Torque Sensor Gear Assembly Overhaul Manual with Illustrated Parts List, 72-00-17, Revision No. 9, dated, July 20, 1992, or earlier versions, to overhaul TPE331 or TSE331 hydraulic torque sensor gear assemblies, P/Ns 3101726-1, -2, or -3.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
