|A Learjet 45 of Luxembourg Air Rescue|
|National origin||Canada and United States|
|First flight||7 October 1995|
|Developed into||Learjet 70/75|
The Model 45 was the first all-new design since the original Learjet, and significantly altered the Learjet line. Through its four primary variants – the original Model 45, the Model 45XR, Model 40 and Model 40XR – it was the Learjet Division's principal product from the 1990s until the introduction of the Model 75 variant in 2012.
- 1 History
- 2 Design and manufacturing
- 3 Variants
- 4 Accidents and incidents
- 5 Operators
- 6 Specifications
- 7 See also
- 8 References
- 9 External links
Development & Production
The Model 45 was developed in the 1990s as a competitor in the "super-light" business jet category, a rival to the popular Cessna Citation Excel / XLS – but sacrificing the Cessna's stand-up room for the Learjet family's traditional high-speed performance.
The Model 45 was Learjet's first completely new ("clean sheet") design since the company's first aircraft (all other models having been evolved from the original 1963 Learjet design, the Model 23). The Model 45 was developed to make Learjets fundamentally more competitive against newer designs from competing manufacturers. But, as a clean-sheet design (starting from scratch), being built to more rigorous (FAR Part 25) rules, than previous Learjets, the aircraft's development took substantially greater time than the development of previous Learjet models.
The development of the LJ45 began in 1989, but was not announced by Bombardier until September, 1992. First flight of the prototype aircraft took place on October 7, 1995 – the 32nd anniversary of the first flight of the original Learjet 23. FAA certification was delayed, and finally granted in September 1997, with the first customer aircraft subsequently delivered in January, 1998. Flying Magazine reports that the Lear 45 was first certified under FAR Part 25 (transport category rules) in 1998.
Initially, delays in production resulted in frustrated customers and lost or delayed revenues. Some customers' orders were delayed more than two years.
Deliveries & Difficulties
Initially, numerous mechanical and electrical problems began appearing in the aircraft after delivery – including cracked windshields, problems with pressurization, fried power distribution panels, and inappropriate alarms. These and other problems commonly forced Model 45 operators to ground their aircraft about once a month, limiting their use.
Problems came to a head in August 2003, when the FAA discovered a defective fastener for the Model 45's horizontal stabilizer could break, sending the airplane into a fatal dive. The FAA grounded all Learjet 45s, across the nation, and they all sat on the ground for a month, while the manufacturer struggled to develop a fix and get it to aircraft in the field.
By 2007, Model 45 operators were said to have a "love-hate" relationship with the aircraft – appreciating its exceptional combination of performance, payload and economics, but frustrated by frequent maintenance problems, often grounding the aircraft, and difficulty getting prompt and adequate product support and parts. However, 10 years later, a 2017 "Used Aircraft Report" by Business & Commercial Aviation magazine indicated that owners now regard the aircraft as "gas-and-go airplane" and credit it "with great reliability," and the article's author, B/CA senior editor Fred George, describes it as "a rock-solid reliable workhorse."
Design and manufacturing
In size, the LJ45 and LJ45XR fit between the smaller Learjet 31 and Learjet 40, at the low end, and the larger Learjet 60 at the top of the Learjet product line. It offers the operating economics typical of a "light" business jet, but the performance and comfort of a "mid-size" business jet.
It has a 1,971-nautical-mile (3,650 km; 2,268 mi) range at Mach 0.81 with four passengers on board.
The plane was designed around a flat-floor cabin, with a non-circular cross-section for additional headroom. Typical interior configuration is eight passenger seats, in a double-club seating arrangement, and a fully enclosed toilet (usable as a 9th seat) and an adjoining 15-cubic-foot baggage area. An external 50-cubic-foot baggage area is also provided.
The Model 45 was Learjet's first "clean-sheet" (all-new) design since the development of the original Model 23. (All previous models had been derivatives of the Model 23, with the wide-fuselage Model 55 and Model 60 utilizing the basic wing design originating in the Model 23, but with extensions and winglets; some however, view the Model 55 as a "clean sheet" design, also.)
Previous Learjet designs had used rigorous, extensive "fail-safe" structures in the wing and tail assemblies, with numerous wing spars providing a highly reinforced structure (derived from the Swiss-designed P-16 prototype fighter that was the original basis for the first Lear Jet) – but the Model 45, instead, used a lighter, less-robust structure, affording less cost in manufacture and lower aircraft empty weights, resulting in improved capacity, efficiency and some performance enhancement (for a given amount of engine power), at a competitive price.
Outwardly, however, the Model 45 retained the traditional Learjet appearance, with its semi-swept wing, T-tail, sharp nose, and wrap-around windshield – while using engines and avionics similar to those in the Model 60.
It also incorporated two conspicuous modifications pioneered on earlier Learjets: the "delta fins" (twin ventral fins, positioned to help stabilize the aircraft in flight, and help right the aircraft in a deep aerodynamic stall) – and winglets (upturned wingtips to reduce induced drag and improve stability). Among other characteristics, the design has reportedly yielded the most benign stall characteristics of any "light" business jet to date (as of 2017).
The Model 45 cockpit is equipped with a four-screen Honeywell Primus 1000 EFIS avionics system., however it uses obsolete CRT screens, rather than modern LCD screens – resulting substantial maintenance costs (though a $300,000 LCD-display upgrade is available).
The aircraft is powered by two DEEC-controlled Honeywell TFE731-20-AR turbofan engines, rated at 3,500 pounds thrust, each, in sea-level temperatures up to 88 °F – a fuel-efficient, "understressed," derated version of the 4,435 lb thrust TFE731-40 – developed specifically for the Learjet 45. Recommended engine TBO (Time Between Overhauls) is 5,000 hours.
At normal atmospheric conditions, zero-wind takeoff runway requirements range from 4,200 feet (for a stripped, basic plane with a basic operating weight of 11,700 pounds) to 5,040 feet for a fully equipped model, with auxiliary power unit (APU) and other upgrades (14,200 lbs).
However, the engine exhibits poor performance in high-density altitude situations (such as takeoff from hot, humid or high-elevation airports), often resulting in long runway requirements. (Engine power deficiency in high-density altitudes was largely resolved by the engine upgrade to the -20BR engine variant in the Learjet 45XR variant of the Learjet 45 – an engine upgrade which is also available as a retrofit to the older Learjet 45, and widely recommended.)
An internal auxiliary power unit (APU), for ground use, provides electrical and pneumatic power, permits easy starts, without ground power units, and enables aircraft cooling or heating while on the ground, without the engines operating. However, the APU was initially optional, rather than standard, equipment.
The wing has 13 degrees of wing sweep with a supercritical airfoil optimized for cruise flight at Mach 0.78. Though there are no leading-edge slats or wing fences, the wing has vortilons on the leading edge, to avoid spanwise flow, and small metal triangles on the leading edge to minimize airflow separation during flight at a high angle of attack.
The Lear 45 was certified under FAR Part 25 (transport category rules), rather than FAR Part 23 (often used in earlier business jets). The stricter Part 25 certification requires greater system redundancy, and requires that the airplane reliably meets the performance numbers published in the aircraft's FAA-approved Pilot's Operating Handbook (POH).
The Learjet 45XR is an upgraded version of the Model 45, introduced in June, 2004, offering substantially higher takeoff weights, faster cruise speeds and faster time-to-climb rates than the Model 45, chiefly through modifications to the engine.
The XR allowed a gross weight 1,000 pounds greater than the original Model 45, greatly increasing payload and fuel/range options. The aircraft also has exceptionally short runway requirements for mid-size bizjets, capable of loaded flights from 4,000-foot runways.
The 45XR's performance and specifications increases are due to the upgrading of the engines to the TFE731-20BR configuration, flat-rated to 3,500 pounds thrust, even at 104 degrees Fahrenheit, well above the 88-degree mark for that power from the original Model 45's TFE731-20 engines.
The Model 40, first delivered in 2003, is a two-foot (24.5 inches) shorter variant of the Model 45, with less passenger room, but otherwise comparable characteristics and performance data.
The Model 40XR, introduced in 2004, is a higher-performance variant of the Model 40, with the same modifications as used to convert the Model 45 into the Model 45XR.
The Model 75’s Honeywell TFE731-40BR engines yield 10% more takeoff thrust (3,850 pounds) than the -20BR engines powering the Model 45XR, cutting required runway length 12%, allowing a sea-level, standard-day takeoff within 4,440 ft., (versus the Model 45XR's fully equipped need for 5,040 ft). In these conditions, the Model 75 can take off from a 4,500-foot runway, with a full load of passengers and fuel, and fly 1,800 nautical miles (2,070 statute miles).
As with the original Model 45, the Model 75 was initially delivered in a stripped-down form, with many features only offered as options, rather than as standard equipment). However, the aircraft does come equipped with an APU, and thrust reversers (rare in light business jets). Early units had minor quality problems and defects.
The Model 70, introduced in 2013, is a shortened variant of the Model 75 – alternatively described as an upgraded Model 40XR, with the same modifications as used to convert the Model 45XR into the Model 75. It was far less popular than the Model 75, and was dropped from the Learjet line in 2015.
Accidents and incidents
- 2008 Mexico City plane crash; On 4 November 2008, Mexican Interior Minister Juan Camilo Mouriño, Assistant Attorney General José Luis Santiago Vasconcelos and 7 others were killed in an accident involving a Learjet 45XR. The aircraft crashed on a busy road, killing another 7 people on the ground. Investigators determined that the pilots had been flying too close to a 767 and lost control after flying into the larger plane's wake turbulence.
- August 2003, a defective fastener for the Model 45's horizontal stabilizer failed in flight, creating the risk of a crash, which was averted. This event led to the FAA grounding all Learjet 45s, nationwide, for a month, while the manufacturer developed a fix and got it out to aircraft in the field.
- June 1, 2003, approximately 1426 local time, a Learjet 45, registration number I-ERJC, operated by Eurojet Italia, crashed shortly after take-off from Milano Linate Airport in Milan, Italy. The airplane reportedly struck a flock of birds shortly after takeoff and crashed into an industrial building while attempting to return to airport. The 2 crew members aboard received fatal injuries.
- Military Technical College MTC
- Eurofly Service
- Medi Business Jet
Data from Brassey's World Aircraft & Systems Directory 1999/2000
- Crew: 2
- Capacity: 9 passengers
- Length: 58 ft 0 in (17.68 m)
- Wingspan: 47 ft 10 in (14.58 m)
- Height: 14 ft 1 in (4.30 m)
- Wing area: 311.6 ft² (28.95 m²)
- Empty weight: 12,850 lb (5,829 kg)
- Max. takeoff weight: 21,500 lb (9,752 kg)
- Powerplant: 2 × Honeywell TFE731-20 turbofan, 3,500 lb (15.57 kN) each
- Maximum speed: 533 mph (463 knots, 858 km/h, Mach 0.81) (max cruise)
- Cruise speed: 510 mph (445 knots, 804 km/h, Mach 0.76)
- Range: 1,968 mi (1,710 nmi, 3,167 km) (4 passengers)
- Service ceiling: 51,000 ft (15,545 m)
- Aircraft of comparable role, configuration and era
- "Learjet 45/40 production list". rzjets.
- "Operations Planning Guide" (PDF). Business & Commercial Aviation. Aviation Week. August 2012.
- Charles, Michael Maya (November 18, 2010). "Lear 45XR: The Swiss Army Knife of Jets: Refining and redefining the super-light jet category". Flying Mag. Bonnier Corporation. Retrieved April 5, 2017.
- Huber, Mark (June 2007). "Learjet 45 & 45XR". Business Jet Traveller. The Convention News Co. Retrieved April 5, 2017.
- George, Fred, "Used Aircraft Report: Learjet 45/45 XR: Fast, efficient, reliable and now less maintenance-intensive," Mar 28, 2017, Business & Commercial Aviation, retrieved April 10, 2017
- "Bombardier Learjet45 Specifications". Airliners. Leaf Group Ltd. Retrieved April 5, 2017.
- Phillips, Don (August 12, 2003). "FAA Grounds All Learjet Model 45 Business Jets". iasa-intl. Retrieved April 5, 2017.
- Gilbert, Gordon, "2005 AIN Product Support Report," October 4, 2006, Aviation International News, retrieved April 5, 2017
- "The Lear Gene". Airport Journals. November 1, 2005. Retrieved April 5, 2017.
- "Bombardier Aerospace Launches Learjet 40XR High Performance Light Jet." from Wings over Kansas Archived 2006-11-14 at the Wayback Machine.
- George, Fred, "Operators Survey: Bombardier Learjet 70/75: Strong resurgence of the last Learjet," Mar 28, 2017, Business & Commercial Aviation, retrieved April 10, 2017
- McMillin, Molly, "Bombardier’s Learjet 75 gets FAA certification," November 15, 2013, Wichita Eagle, retrieved April 5, 2017
- Accident Report: NTSB Identification: DCA03WA037," National Transportation Safety Board, citing the foreign investigating agency, Italy's Agenzia Nazionale per la Sicurezza del Volo (ANSV); retrieved April 10, 2017
- "Air Corps: Organisation: Fleet". Óglaigh na hÉireann: Defence Forces Ireland. Retrieved 21 October 2012.
-  "Perfil newspaper"
- Michael John Haddrick Taylor (1999). Brassey's World Aircraft & Systems Directory, 1999/2000. Brassey's. ISBN 1-85753-245-7.
|Wikimedia Commons has media related to Learjet 45.|
- Fred George (Mar 28, 2017). "Used Aircraft Report: Learjet 45/45 XR". Business & Commercial Aviation. Aviation Week.</ref>