Learjet 45XR Retrofit
In the early months of 2004, Bombardier began offering Learjet 45 owners the option of upgrading their aircraft to the Learjet 45 XR model. The retrofit is offered as a series of service bulletins that upgrade an in-service Learjet 45 to the Learjet 45 XR variant. Dozens of private jet owners have opted to upgrade their aircraft since the retrofit option became available – but what does the XR retrofit really add to the aircraft?
The most readily apparent change between the Learjet 45 and Learjet 45 XR is the enhancement to the engines. Newer TFE731-20BR engines replace the older TFE731-20 engines used on the Learjet 45. The change in engine doesn’t impact maximum thrust or engine inspection intervals. The benefits of the upgrade are actually driven by a change in the engine flat-rating which allows the engine to produce more thrust under demanding conditions where thrust was limited on the older engines. Therefore, although the upgrade increases climb and speed capability on a standard day, the benefits are most apparent when considering operations under challenging conditions.
For example, the XR retrofit dramatically improves hot and high runway performance. At sea level and on a standard day the Learjet 45 and Learjet 45 XR require approximately the same runway length (when taking off at the same weight). When the runway is elevated to 5,000 feet and the outside air temperature increases to 25 deg C. (77 deg F.), at a takeoff weight of 20,500 lb the Learjet 45 uses 7,275 ft of runway. The Learjet 45 XR needs only 5,565 ft to take off under the same conditions. Operating out of a very short runway, where operators are often forced to off-load fuel in order to lower aircraft weight and shorten take-off distances, the improved field performance of the XR can translate into a considerable range advantage. For example, out of Aspen on a 68 deg F day, the Learjet 45 XR can fly 1,000 nm further than the Learjet 45 with 6 passengers.
In addition to runway performance the XR upgrade impacts speed and climb characteristics. In fact, under standard ISA conditions at a typical mid cruise weight of 18,000 lb, the Learjet 45 XR can cruise up to 8% faster than the Learjet 45 at FL470, and 4% faster at FL450. But again, the benefit of the upgrade is most noticeable under the elevated temperatures seen in the U.S. and Europe during summer months, and year-round in many areas such as Africa and the Middle East. For example, the Learjet 45 XR can cruise up to 19% faster than the Learjet 45 under ISA+15 deg conditions, and can climb to cruise altitude much faster than the Learjet 45.
Finally, the XR retrofit kit is sold with an increase to MTOW. The 1,000 lb weight increase significantly increases useful load under all operating conditions and is so popular it is often bought as a stand-alone service bulletin. For example, w ith full fuel, the Learjet 45 XR can carry 1,575 lb of payload and the L45 can carry 575 lb of payload. In layman’s terms, the Learjet 45 XR can carry an additional 1,000 lb of either people or baggage when the tanks are full.
The Learjet 45 XR retrofit offers the enhanced performance of the Learet 45XR to current Learjet 45 owners. The speed and climb improvements under typical conditions are substantial, but the retrofit will offer the most value to owners that frequently operate in hot and or high environments, or out of short airfields. For those who plan on keeping their Learjet 45 for a while longer, the $575,000 XR retrofit may be well justified.