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Aviation Torque Unit Converter

Convert torque between Newton meters (N·m), pound-feet (lb·ft), pound-inches (lb·in), ounce-inches (oz·in), and kilogram-force meters (kgf·m). Essential for aircraft maintenance, engine overhauls, and structural assembly where torque specs vary by manufacturer (Boeing, Airbus, Bombardier).


Torque Conversion Tool

Critical: Always verify torque specifications in the approved maintenance manual. Incorrect torque can lead to structural failure or component damage.

Torque Unit Usage by Region and Manufacturer

While torque values must always be sourced from the applicable maintenance manual, unit conventions vary predictably. Aircraft maintenance manuals specify torque in different units depending on region and OEM:

Region / OEM Primary Torque Unit Typical Applications
Boeing (USA) lb·in, lb·ft Airframe structural, engine mounts
Airbus (EU) N·m Most airframe and system installations
Engine OEMs (CFM, P&W, GE) N·m or lb·ft Depends on engine program & customer spec
General Aviation (Cessna, Piper) lb·in Light-aircraft hardware, avionics
EASA / FAA Advisory Material Both, with N·m preferred in newer docs AMC/GM, ACs, SBs

Note: Always consult the current maintenance manual — torque values are critical for safety.

Torque Conversion Best Practices

Reference: FAA AC 43.13-1B §7-2, EASA Part-145.A.30(b)

How Torque Is Specified in Maintenance Manuals

Here's how torque instructions typically appear — and what to look for:

STEP 5: Tighten bolt (P/N XYZ) to 45 ±5 N·m.
Base value + tolerance, SI units
Caution: Torque to 60 in·lb (6.8 N·m). Over-torquing may damage composite fitting.
Dual units + safety note
Ref: Table 201, Column C — Torque: 180 lb·ft @ 70°F. Re-torque after 10 flight cycles.
Conditional value + maintenance note

Torque & Fastener FAQ

In aviation, precision is key. Foot-pounds (ft-lb) are typically used for high-torque applications like landing gear bolts or engine mounts. Inch-pounds (in-lb) are used for smaller, more delicate fasteners like access panels or spark plugs.

Calculation: 1 ft-lb = 12 in-lb. Always double-check your torque wrench scale to ensure you aren't over-torquing by a factor of 12!

Newton Meters (Nm) is the SI unit for torque. You will primarily find Nm specifications in maintenance manuals for European-manufactured aircraft (like Airbus or Leonardo) or modern engine components (like Safran or Rolls-Royce). Most US-made aircraft (Cessna, Piper, Boeing) still primarily use Imperial units (in-lb/ft-lb).

Yes, significantly. Torque values in manuals are usually specified for "Dry" threads unless stated otherwise. If you apply oil or anti-seize to a bolt and use the "Dry" torque value, you may over-stress the bolt because the lubrication reduces friction, allowing the bolt to stretch further than intended. Always follow the AMM (Aircraft Maintenance Manual) instructions regarding thread lubrication.

If you use an extension (like a "crow's foot") that increases the effective length of the torque wrench, the indicated torque on the handle will be lower than the actual torque applied to the fastener. In these cases, you must use a specific formula to calculate the corrected setting:
Set Torque = (Actual Torque × Wrench Length) / (Wrench Length + Extension Length)