What Exactly Is the Difference Between the Learjet 45 and 45XR?

The Learjet 45XR is an upgraded version of the original Lear 45, introduced in June 2004. The 45XR model is equipped with Honeywell’s upgraded TFE731-20BR engines, compared to the 45 model’s TFE731-20 engines. The BR engines allow the 45XR to fly into higher altitude airports, carry a heavier payload, takeoff in higher temperatures, climb to cruising altitude nearly 40 percent faster, fly at faster cruise speeds at any given altitude, and land and takeoff on shorter runways.

Here are some specific examples from Bombardier of the XR’s improved performance:

With a takeoff weight of 21,500 pounds on the same runway, a Learjet 45 with the BR upgrade can take off in 8˚C to 12˚C higher temperatures than one with AR engines.

Mach .81 vs. Mach. 78 at ISA (FL430, 18,000 pounds) and Mach .81 vs. Mach .75 at ISA+10 degrees Celsius (FL410, 18,000 pounds).

At a field elevation of 5,000 feet, the required runway length is reduced by as many as 2,500 feet (ISA +25 degrees C).

Out of Aspen, the BR-equipped aircraft will carry 2,500 pounds more weight (resulting in about 1,000 nautical miles more range with eight passengers).

The upgrade to BR engines requires three Learjet service bulletins, one of which incorporates two Honeywell bulletins:

• Learjet Service Bulletin 45-11-4: Maximum Takeoff Weight Increase
• Learjet Service Bulletin 45-22-5: Honeywell Avionics Phase IV
• Learjet Service Bulletin 45-72-1: BR Engine Upgrade
  • Honeywell SB TFE731-76-5120: Install Digital Electronic Control Part No. 2118882-1008
  • Honeywell SB TFE731-72-5169: Convert Engine TFE731-20AR-1B to TFE731-20BR-1B

Depending on the serial number of the aircraft, certain prerequisites may or may not be required to complete the upgrade:

• S/N 45-001 to 45-052 need their “R” engines upgraded to “AR” before the “BR” upgrade can be performed.
• S/N 45-236 and subsequent don’t require Phase IV avionics upgrade.
• SN 45-238 and earlier require an N2 margin inspection prior to or concurrent with BR upgrade.
• SN 45-239 and later do not need the N2 run if they have 400 hours or less on engines and N2 margin was OK when new.

In order to retain the functionality the Lear 45 FMS system’s performance database, the FMS system (or systems) will need to undergo a software upgrade, as well, to remain compatible with the 45XR’s BR engine performance and increased maximum takeoff weight.

Have you flown both the Lear 45 and Lear 45XR? Let us know if you think the improved performance is worth the upgrade!

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