Bolting the Longhorn wing onto the Model 35 fuselage gave Learjet the fastest-climbing light jet of its generation without the cost of a clean sheet airframe. Delta fins went under the tailcone, the tip tanks came off in favor of winglets, and the Learjet 31 left the ground on 11 May 1987.
Production ran to October 2003 and 246 airframes, and most of the fleet is still working in charter, air ambulance and corporate hands. This page covers the Learjet 31 and 31A specifications, history, variants and approved tire fitments.
Learjet 31 Specifications
Figures below are for the Learjet 31A, the definitive production standard. Differences from the original Model 31 and the 31A/ER are noted.
| Manufacturer | Learjet, Wichita, Kansas. A Bombardier subsidiary from 1990 |
| Type | Light business jet |
| First flight | 11 May 1987 |
| Certification | Model 31 certified 1988. The 31A was announced in 1990 and entered service on 15 August 1991 with serial 31A-035 |
| Production status | Out of production. Final delivery 1 October 2003 |
| Units built | 246 Model 31 and 31A airframes. 38 were base Model 31s. Last serial 31A-242 |
| Engines | 2 x Honeywell TFE731-2 turbofan, 3,500 lb thrust each. TFE731-2C on aircraft from the 2000 revision |
| Max range | 1,631nm (3,021km) with four passengers and standard fuel. 1,911nm for the 31A/ER |
| Normal range | 1,211nm |
| Cruise speed | 441 KTAS normal cruise, 462 KTAS maximum. Mach 0.81 Mmo |
| Max operating altitude | 51,000ft |
| Rate of climb | 5,480 ft/min at sea level. 1,610 ft/min single engine |
| Balanced field length | 3,800ft at sea level ISA |
| Landing distance | 4,200ft landing field length |
| Max takeoff weight (MTOW) | 17,200 lb (7,802 kg) for later 31As. 15,500 lb for the original Model 31 |
| Max landing weight | 16,000 lb |
| Fuel capacity | 4,124 lb usable |
| Cabin | 12ft 11in long, 4ft 11in wide, 4ft 4in high. 271 cu ft, plus 40 cu ft internal baggage |
| Passenger capacity | 6 typical, 8 maximum |
| Crew | 2 pilots |
| Price (used) | Approximately $499,000 to $1.3 million in 2026 depending on year, hours and engine program status |
| Operating cost | Approximately $2,800 per hour variable at 250 hours a year. Nearer $4,400 all in including fixed costs |
Learjet 31 – History and Overview
Development and Background
The Model 31 came out of a parts-bin calculation rather than a market study. Learjet already had the 35 and 36 fuselage in production with the TFE731 installation sorted, and it already had the Longhorn wing from the 28, 29 and 55 programs on the same shop floor. Putting one on the other produced a light jet with modern aerodynamics at a development cost the company could actually fund.
Ownership changed twice while the aircraft was being built. Gates Learjet sold the business to Integrated Resources, which sold it on to Bombardier in 1990, and the 31 spent its early production life inside a company that was changing hands around it. First flight was 11 May 1987 and certification followed in 1988.
The original Model 31 did not sell. Thirty-eight were built before the type was replaced. The cabin was small, baggage space was poor, there was no galley, and deleting the Model 35 tip tanks in favor of winglets cost range that buyers were not willing to give up.
Design and Performance
Delta fins under the aft fuselage are the type signature and they do real work. They improve directional stability at high angles of attack and clean up the stall behavior that earlier Learjets were known for, which matters on an aircraft with a wing this clean and this heavily loaded.
Climb is what operators remember. 5,480 ft/min off the runway and a direct climb to the mid forties puts the aircraft above most weather and most traffic inside twenty minutes of brake release, and the certified ceiling is 51,000ft. Single engine climb holds up at 1,610 ft/min, which is better than several newer light jets manage on two.
The trade is cabin and range. 271 cu ft with 4ft 4in of headroom is tight for six, and 1,211nm of normal range turns a US transcontinental leg into a two-stop exercise. The 31A/ER answered with additional fuel and a maximum range of 1,911nm.
Variants
- Learjet 31: original production model from 1988. TFE731-2 engines, 15,500 lb gross. 38 built.
- Learjet 31A: announced 1990, in service from August 1991. Bendix King EFIS 50, dual KFC 3100 autopilot and flight director, revised panel and a higher cruise speed.
- Learjet 31A, 2000 revision: higher takeoff and landing weights, N1 engine control, thrust reversers as standard, TFE731-2C engines and an R134A air conditioning system. The designation did not change.
- Learjet 31A/ER: extended range version with additional fuel and a higher takeoff weight, rated at 1,911nm. An optional further tank adds about 500 lb of fuel and roughly 200nm.
Operators
Corporate flight departments and charter operators took the bulk of the fleet, and more than 200 were in service worldwide at the type peak. Air ambulance operators are the other significant group, drawn by the climb rate and the block speed rather than the cabin, since a 31A will beat most light jets to altitude with a patient on board.
Government and liaison use accounts for a smaller share, with examples in service in Latin America, Europe and Asia. NASA has also operated the type.
Current Status
Production ended on 1 October 2003 and Bombardier closed the Learjet line entirely in 2021, with the last Learjet 75 delivered in 2022. Component and engine support continues through Bombardier and the aftermarket, and the TFE731 is supported by Honeywell and multiple independent shops. Listings are thin, usually in single figures worldwide at any one time.
Asking prices in 2026 run from around $499,000 for a high-time early 31A to roughly $1.3 million for a late low-hours aircraft on an engine program. Engine program status drives valuation on this type more than airframe hours do, and a pre-purchase inspection that covers hot section condition is worth more than one that covers paint.
Learjet 31 Landing Gear and Tires
Landing Gear Configuration
The 31 uses a hydraulically actuated retractable tricycle undercarriage with a single wheel at each of the three positions. The main legs retract inboard into the fuselage and the nose gear retracts forward. Nose steering is steer by wire, and multi-disc brakes with anti-skid handle the stopping.
A full tyre shipset is three, which keeps consumable cost per cycle low for an aircraft of this performance. That is a meaningful operating advantage over four-wheel light jets when the type is flown at charter utilization.
One tire-specific airworthiness directive is worth knowing. FAA AD 2001-07-11 covered Models 23 through 55, including the 31 and 31A, and required a one-time visual inspection of Goodyear 178K23-5 main gear tires within a specific manufacturing serial range following reports of tread separation. Affected tires had to be replaced before further flight and could not be installed afterwards.
Learjet 31 Tire Specifications
| Main gear tire size | 17.5×5.75-8 |
| Main gear ply rating | 12PR, tubeless |
| Main gear speed rating | 210 mph |
| Nose wheel tire size | 18×4.4, dual deflector type |
| Nose wheel ply rating | 10PR, tubeless |
| Nose wheel speed rating | 210 mph |
| Wheels per position | One main wheel each side, one nose wheel. Three tires per shipset |
| Construction | Bias ply |
| Tire pressure | Refer to the Learjet 31 aircraft maintenance manual |
| Compatible brands | Goodyear, Michelin |
| Part numbers | Main: Goodyear 178K23-5, Michelin 038-627-0. Nose: Goodyear 184F10-2, Michelin 031-613-8, 031-613-4, 027-613-0 |
Always verify tire size, ply rating and part number against the aircraft maintenance manual, the illustrated parts catalog and applicable airworthiness directives before ordering. Serial number, variant and installed modifications can affect tire requirements.
Main Gear Tires
Each main leg carries a single 17.5×5.75-8 at 12 ply, rated to 210 mph. Goodyear lists the Flight Eagle 178K23-5 against the Lear 31, 35 and 36 in its application data, and Michelin covers the same size and rating with the Aviator 038-627-0, which DMI Aviation carries as a direct cross reference.
The trap on this size is ply rating. The 14-ply version of 17.5×5.75-8 is the Learjet 55 and 60 fitment, and the 10-ply version belongs to the Embraer Legacy and Praetor nose position. All three look identical on a shelf label. Order by part number, not by size.
Nose Wheel Tire
The nose takes an 18×4.4 at 10 ply, specified as dual deflector type so that water and slush are thrown clear of the aft-mounted engine intakes. Goodyear 184F10-2, product code 301-336-340, is the fitment listed for the Learjet 20 and 30 series and the Citation I.
Several other 18×4.4 10-ply tires exist in plain rib form for Cessna and Beechcraft applications, so confirm the deflector configuration against the illustrated parts catalog rather than matching on size and ply alone. Michelin 031-613-8 is the double chine option in this size.
Approved and Compatible Brands
The following tires are listed in the correct sizes and ply ratings for the Learjet 31 and 31A:
- Goodyear Flight Eagle 178K23-5: 17.5×5.75-8, 12PR, 210 mph, main gear. Listed by Goodyear for the Lear 31, 35 and 36
- Michelin Aviator 038-627-0: 17.5×5.75-8, 12PR, 210 mph, main gear. Direct cross reference to 178K23-5
- Goodyear Rib 184F10-2: 18×4.4, 10PR, 210 mph, nose gear. Product code 301-336-340
- Michelin Air 031-613-8: 18×4.4, 10PR, 210 mph, double chine, nose gear. Confirm applicability against the IPC
- Michelin 031-613-4: 18×4.4, nose gear. Listed as a cross reference to 184F10-2 in the same size and rating group
- Michelin Air 027-613-0: 18×4.4, nose gear. Listed as a cross reference to 184F10-2 in the same size and rating group
- Goodyear 184F03-2: 18×4.4, nose gear. Listed as a cross reference to 184F10-2 in the same size and rating group
Frequently Asked Questions
Is the Learjet 31 still in production?
No. The last Learjet 31A, serial 31A-242, was delivered on 1 October 2003, and Bombardier closed the Learjet production line entirely in 2021. Tires, brakes, wheels and engine support remain readily available, since the fitments and the TFE731 are shared across a large installed base.
What are the Learjet 31A specifications?
Two Honeywell TFE731-2 turbofans of 3,500 lb thrust each, 17,200 lb maximum takeoff weight, 51,000ft certified ceiling, 441 KTAS normal cruise and six to eight seats behind a crew of two. The full table above lists weights, dimensions and field performance.
What is the range of the Learjet 31A?
Maximum range is 1,631nm (3,021km) with four passengers and standard fuel, and normal range is nearer 1,211nm. The 31A/ER carries additional fuel and is rated at 1,911nm, with an optional further tank worth roughly 200nm more.
What is the difference between the Learjet 31 and the 31A?
The 31A arrived in 1990 with Bendix King EFIS 50 avionics, a dual KFC 3100 autopilot, a revised panel and a higher cruise speed. A second revision in 2000 added higher takeoff and landing weights, N1 engine control, standard thrust reversers and TFE731-2C engines without changing the designation. Only 38 base Model 31s were built against 208 of the 31A.
What is the Learjet 31A price?
Used asking prices in 2026 run from around $499,000 for a high-time early aircraft to roughly $1.3 million for a late low-hours example. Engine program enrollment moves the number more than airframe hours do, since an unenrolled pair of TFE731s carries a significant overhaul liability.
What does the Learjet 31A cost to operate per hour?
Variable costs run around $2,800 per hour at 250 hours a year, covering fuel, engine reserves, maintenance and landing fees. Including fixed costs such as crew, hangarage and insurance brings the all-in figure closer to $4,400 per hour at that utilization. Charter rates are typically quoted between $3,200 and $4,200.
Where can I find a Learjet 31 for sale?
Listings appear on Controller, GlobalAir, Trade-A-Plane and AircraftExchange, with inventory usually in single figures worldwide. A pre-purchase inspection focused on engine hot section condition and landing gear overhaul status is the sensible priority on an airframe of this age.
What interior options does the Learjet 31 offer?
Standard layouts seat six in a double club or a four-place club with a two-place divan, with a forward refreshment center and an aft lavatory. Cabin height is 4ft 4in and volume is 271 cu ft, so the interior is close-coupled by midsize standards. Air ambulance conversions replace the aft seating with a stretcher installation and medical panel.
What is the Learjet 31A landing distance?
Published landing field length is approximately 4,200ft at maximum landing weight in standard sea level conditions, against a balanced field length of 3,800ft for takeoff. Both figures move with weight, altitude and temperature, and anti-skid serviceability matters on the shorter runways the type is often asked to use.
What tire size does the Learjet 31 use?
Main gear tires are 17.5×5.75-8 at 12 ply, one per leg, and the nose carries an 18×4.4 at 10 ply in dual deflector form. Three tires make a full shipset. Verify size, ply rating and part number against the maintenance manual and parts catalog for your serial number before ordering.
Which tire brands are approved for the Learjet 31?
Goodyear and Michelin both produce tires in the correct sizes and ratings. Goodyear lists the Flight Eagle 178K23-5 for the main gear and the 184F10-2 for the nose, with Michelin covering the main position through the Aviator 038-627-0 and the nose through several cross-referenced part numbers.
How much do Learjet 31 tires cost?
Pricing varies by brand, construction and quantity. Main gear tires in 17.5×5.75-8 12PR and nose tires in 18×4.4 10PR sit in broadly similar territory, and with only three tires per shipset the Learjet 31 is cheaper to keep in rubber than most jets of comparable performance. Current pricing is shown on the product listings linked above.
What is the tire pressure for the Learjet 31?
Inflation pressures are published in the Learjet 31 aircraft maintenance manual rather than in public documents, and they differ between the nose and main positions. Check them cold and verify the correct values for your serial number before servicing.
How long do Learjet 31 tires last?
Main gear tires on light jets in this class typically give 100 to 300 landings depending on runway surface, landing weight and braking technique, with the nose tire usually lasting longer. The maintenance manual and the operator maintenance program set the specific limits.
How often should Learjet 31 tires be changed?
Replacement is driven by tread wear indicators, cuts, flat spots, cord exposure, cycle counts and calendar limits rather than a fixed interval. Anti-skid faults and heavy use of maximum braking accelerate wear noticeably on this type. A licensed engineer working from the maintenance manual makes the final call.
