4G6320A00132
GEARBOX
Specifications
- Part Number
- 4G6320A00132
- Manufacturer
- AGUSTA
- ATA ChapterMaintenance system chapter
- 63 — Main Rotor Drive(s)
- CapabilitySystem area (hydraulics, avionics, landing gear…)
- Engine Accessories
- Inventory ClassRotable, expendable, or consumable
- Rotable
- Certification
- OEM
- Aircraft Category
- General-Aviation
- Criticality
- Critical & Life-Limited
Service Reliabilityfrom FAA SDR (Service Difficulty Reports)
- SDR reports
- 7
- Replace events
- 1
- Repair events
- 2
- K-code events
- 1
Directional indicator only. Reflects what operators reported to the FAA when a difficulty was logged — not a fleet-normalized failure rate or a cost-based BER. Use alongside operator-specific data.
Airworthiness Directive coverage
FAA / EASA public regulatory data
- FAAAD 2022-27-03effective Jan 31, 2023Prohibition
The FAA is superseding Airworthiness Directive (AD) 2021-20-10 for certain Leonardo S.p.a. Model AB139 and AW139 helicopters. AD 2021- 20-10 required removing from service a certain part-numbered main gearbox (MGB) spherical bearing lock nut (lock nut) that is installed on certain part-numbered MGBs and replacing it with a newly designed MGB lock nut. AD 2021-20-10 also prohibited installing any MGB with the affected MGB lock nut and prohibited installing any affected MGB lock nut on any helicopter. Since the FAA issued AD 2021-20-10, it was discovered that a part number (P/N) was incorrectly listed and that the applicability needed to be clarified. This AD retains the requirements of AD 2021-20-10 and clarifies the applicability. The FAA is issuing this AD to address the unsafe condition on these products.
- FAAAD 2021-20-10effective Nov 22, 2021Prohibition
The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. Model AB139 and AW139 helicopters. This AD was prompted by a report of several occurrences of a cracked main gearbox (MGB) spherical bearing lock nut (lock nut). This AD requires removing from service a certain part-numbered MGB lock nut that is installed on certain part-numbered MGBs and replacing it with newly designed MGB lock nut. This AD also prohibits installing any MGB with the affected MGB lock nut and prohibits installing any affected MGB lock nut on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
Directives citing this part number in the FAA / EASA regulatory corpus we have processed — not a complete historical AD list. An AD is a compliance requirement that drives scheduled work (inspections, replacements, modifications) on the fleets that carry the part; a directive naming this PN as the replacement part is install demand, not an action against it — and none of this is a prediction that the part will fail.
Airframe Applicability(2)
Data Sources(1)
- 2026-03-07
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