The G 120TP is the end of a family line that began far from military aviation. Grob’s G 109 motor glider first flew in 1980; its composite construction and benign handling led to the G 115, a piston trainer that, by Grob’s account, was adopted by ten air forces. The RAF alone operated a large fleet of G 115Es as the Tutor T1 for elementary and university air squadron flying.

The G 120A added retractable gear, more power and a more military cockpit, and was sold to several air forces and contract training providers. The obvious next step was the turbine. Swapping the piston for a Rolls-Royce M250, an engine best known in helicopters, gave a trainer that ran on the same jet fuel as the rest of an air force’s fleet, with smoother handling and better reliability than a piston engine. In development the changes multiplied, until the G 120TP emerged as essentially a new aircraft, first flown in 2010.

The timing suited the market. Many air forces were replacing ageing piston trainers and looking for a cheaper stage below a PC-21, Texan or KT-1. Grob offered the aircraft with ground-based training systems, simulators and selection software, and its customers increasingly bought a complete training package rather than a fleet of aeroplanes alone.

Grob has sold the G 120TP as a configurable platform. Early export aircraft, such as Indonesia’s, were described with Martin-Baker Mk 15B ejection seats and an Esterline Cockpit 4000 avionics suite with two large flat-panel displays. Later aircraft use the Genesys Aerosystems IDU-680 electronic flight instrument system with up to four 6 by 8 inch displays, the same family Grob uses on its G 520NG high-altitude aircraft. Martin-Baker’s lighter Mk 17 seat is also offered.

Other options include an autopilot, air conditioning and an oxygen system, the last needed if instructors use the aircraft’s 25,000 ft ceiling; the RAF limits its Prefects to 10,000 ft operationally. The constant across all versions is the HOTAS layout and the side-by-side cabin, which make the type an elementary trainer, an instrument trainer and an introduction to the switchology of a combat aircraft at once. Training systems complete the package: Grob offers computer-based training, a full-mission simulator with a wide-angle visual system and a pilot selection and evaluation system intended to reduce attrition.

• Indonesia: launch customer, 18 ordered in 2011 with deliveries from 2012, later increased.
• Argentina: 10 aircraft, deliveries from 2013.
• Mexico: 25 aircraft delivered 2015 to 2016.
• Myanmar: 10 received by July 2015, with more ordered.
• Jordan: King Hussein Air College, replacing Slingsby T67M260 Fireflies from 2017.
• United Kingdom: 23 Prefect T1s for the UK Military Flying Training System, operating from 2017 at RAF Barkston Heath and Cranwell; two further aircraft at the Empire Test Pilots’ School.
• Bangladesh: 24 ordered in 2021.
• Sweden: SK 40 at Malmen, first aircraft handed over in April 2023.
• Canada: 23 CT-102B Astra II, first two received in September 2025 for 15 Wing Moose Jaw.
• Also Ecuador and Ethiopia, and US Army students through a CAE academy at Dothan, Alabama.
• Many customers buy the aircraft with Grob’s ground-based training, simulators and maintenance support, and several fleets are owned or operated through contractors rather than by the air force alone.

No operator publishes an hourly cost, so MiGFlug’s figure is an estimate. The M250 is a small engine by turboprop-trainer standards, less than half the power of a PC-21’s, and the airframe is light, composite and corrosion-free, with a quoted 15,000-hour fuselage life. Maintenance is often bundled into the contract: in Sweden Grob itself provides line and heavy maintenance.

On the basis of light turbine aircraft of similar power and weight, a range of roughly US$600 to US$1,200 per flight hour including fuel and maintenance reserves is plausible, more than a piston trainer but far less than the larger turboprops and jets it feeds. That gap is the type’s whole argument: students can learn aerobatics, instrument flying and turbine handling in it before moving on to an aircraft that costs several times as much an hour. Canada’s arrangement, in which the air force owns the aircraft but a contractor delivers the training, shows how such costs are increasingly managed through long-term service contracts rather than per-hour budgets.