Beyond Basics
In mid May I and on behalf of FLIGHT, I was given the opportunity to revisit Grob Aviation at their production facility and airfield at Mattsies-Tussenhausen in Bavaria,Germany and to evaluate the full digital cockpit of the latest production version of the turbo-prop powered G120TP, 2 seat military trainer. This was an aircraft that had so impressed me in its prototype form when I tested it for FLIGHT in late 2010. The aircraft’s incredible blend of high performance, low acquisition or lease price, minimal operating costs and massive training potential, was clearly evident to me then and I predicted at that time that this aircraft was destined to become the new 21st century Flight, Attack and Systems Trainer (FAST) aircraft of choice for Air Force Training Organisations, worldwide. Additionally, with the aircraft incorporated within a ‘systems of systems’ training concept, it would make the present definitions of grading, elementary, basic and advanced lead-in training phases redundant and with the aircraft having the potential to revolutionise future military training standards, beginning from a student’s first day.
The aircraft gained EASA CS 23 certification in early 2013 and is on course to gain FAA FAR 23 certification in early 2015. Since EASA certification, the aircraft has been bought by Indonesia (16), Argentina (12) and Mexico (40+). There is also the likelihood of another, very significant, order from a major European Air Force, to be announced around the Farnborough Air Show in July. With this order in place, I believe my prediction of the aircraft’s breakthrough success is starting to become true.
The initial EASA CS 23 certification basis of the G120TP was with an analogue cockpit. The new digital cockpit will be classed as a ‘major change’ to the Aircraft’s Type Certificate (TC) under EASA regulations. The ‘major change’ will cover either an option for a version with a 2 screen digital display (to one cockpit side with analogue instruments on the other cockpit side) or an option for a version with a full, 4 screen digital display, endowing the G120TP with a totally glass cockpit and, for the very first time, individual ‘side by side cockpits’ for both student and instructor (as opposed to ‘side by side seating’). Grob believe that the full, 4 screen digital display version will be the most popular option and it was this 4 screen G120TP cockpit version that I evaluated (on the ground only because of approval and engineering constraints) at Grob. Grob Aviation is on schedule to gain EASA certification for the new G120TP digital cockpit (in either 2 or 4 screen versions) in July of this year.
Updates
In terms of limitations the aircraft is virtually unchanged from the prototype. Vmo is now 238 KIAS (previously 245 KIAS) and the Max Take Off Weight is 1515 kg (previously 1590 kg). Aircraft improvements include a new undercarriage that allows the aircraft to sit level rather than the tendency for the prototype to sit slightly tail down; the external power connection point is now behind the right wing root; the gaseous oxygen bottle and system is now fully enclosed within the baggage area and the oxygen hose and mic-tel connections have been simplified and tidied; the flap lever has been remodelled and has 4 positions of Up/Take Off/Land/Full; the power lever features a mechanical ‘stop’ (that can be overridden) set to approximate 300 SHP for early student flying and circuit flying. The aircraft features electric trim in all 3 axes and pitch trim is shown as a ‘green band’ within the Engine Indicating and Crew Alerting System (EICAS) display.
Grob have decided not to progress a Helmet Mounted Display (HMD) system because most Air Force customers did not want this option at the ‘early student’ experience level. Additionally, the Martin Baker Mk15B zero-zero lightweight ejection seats are not presently to be fitted but this requirement is on an engineering ‘hold’ only and remains a firmly defined future option as Grob looks at potential G120TP upgrades/variants including increased weights, strengthened wings with wet/hard points, more powerful engine options, tandem seat and 4 seat fuselage versions.
With superb aerodynamics and light weight granted by its all carbon construction and outstanding ‘jet like’ performance and economy delivered by its Rolls Royce 250-B17F turbo-prop engine (450 SHP) married to its 5 bladed, short span MT propeller; the critical element in the role of the G120 TP as a 21st century trainer aircraft, when set within an overall ‘system of systems’ training concept, was always going to be a truly advanced digital cockpit. This would then be a trainer that would fit seamlessly with other modern (business type) fixed wing aircraft and helicopters, acting in the advanced training role for transport and rotary wing students, as well as the higher performance turbo-prop trainers, such as the PC-21 or the T-6C, and ‘top end’ Lead In Fighter
Trainers (LIFT), such as the Hawk T2 or the Aermacchi M-346, for fighter pilot training.
All of these later modern trainer aircraft will have digital avionics and display screens as will the modern operational aircraft they train for, in front line service.
Technical Background
The cockpit features 4 screens, set side by side, each 6”x8” (10.4” diagonally) in size, set long side vertical (portrait sense) and each ‘pilot ‘pair’ of screens separated centrally by a large combined digital standby attitude indicator; UHF radio panel; autopilot panel, gear panel and 3 function and warning buttons. A standby compass is the only instrument on top of the cockpit glareshield and set centrally. The digital screens and autopilot are made by Genesis Aerosystems (formally Cobham).
Each screen can be full size or split into two separate display areas (upper and lower) to give up to 8 individual screens in total. Each display unit is identical and interchangeable as a hardware unit. Each display unit includes the functions of an integrated Flight Management System (FMS) with Area Navigation (RNAV), Terrain
Awareness Warning System (TAWS) and digital flight recorder. Connected sensors include a GPS module and an Air Data and Heading Attitude Reference System (ADHARS). The information from the individual avionic units to the screens is carried primarily by an ARINC 429 databus.
Instructor Pilot and student displays can be segregated as two independent systems or joined together as a single system with a panel mounted switch. When re-joined, either side can be synchronised with the other as the master. The centre displays are nominated as those for the virtual training modes (such as the embedded simulation of Air to Air radar modes or Tactical Air Situation display). When not in virtual training mode, the two inner screens are nominated as the Multi Function Displays (MFDs) and the two outer screens as the Pilot Flying Displays (PFDs).
The top half of each outer screen (PFD) is fixed and will always carry the Pilot Flying Instrumentation (PFI) which features either conventional analogue dials or the more modern vertical tape (selectable in cockpit) depiction of altitude; airspeed, vertical speed and heading. Basic flight information is combined with a synthetic grid depiction of terrain; ‘Highway in the Sky’ flight guidance; Course Deviation Indicator (CDI); flight path vector (FPV) and aircraft attitude reference symbology.
The other 6 (half) screens can then carry a fully variable combination of: Moving MAP (including terrain, terrain awareness, landmarks, flight planned route, waypoints); Horizontal Situation Indicator (HSI) for basic display of VOR, ADF and TACAN bearing needles shown in a compass rose format; NAVLOG Overview page acting as a FMS; Audio/Radio page combining VHF/UHF/Transponder/NAV/Intercom; Traffic Alerting and Collision Avoidance System (TCAS); Engine Indicating and Crew Alerting System (EICAS).
By Standard Operating Procedure (SOP), one display screen (half) will always carry the EICAS page. Significantly, the avionics, autopilot and displays will be certified for Vertical Navigation (VNAV) flight path functions and Satellite Based Approach System (SBAS) approaches replicating ILS type guidance to ILS limits, at austere airfields.
Evaluation
The first impression when seeing the cockpit for the first time, especially when the screens were already powered up, was of a totally glass cockpit that completely filled the instrument console area from side to cockpit side and with a displayed screen area that is not only unmatched in this class of trainer but also exceeds most, if not all, advanced modern trainers now presently in use. The glareshield has been lowered by 22 mm on the production version (compared to the prototype) so field of view over the nose was excellent and not compromised by fitting the 4 screens and having to configure the other cockpit controls and indicators (such as autopilot panel and gear handle) around them.
The second impression was of a cockpit with an absolute wealth of digital information; from 8 screens that could be configured to be exactly what the student or instructor pilot wanted, when they wanted them, on what side of the cockpit and for what flight or training event. It is hard to convey in simple words just how flexible the display variations were and how easy it was for me, as a pilot, to configure the cockpit in a way I would want for myself or expect for any future transport, helicopter or fighter graded student. It was also important to remind myself that individual screens were not locked into individual display modes but could be placed anywhere (excepting the PFI on the two outer PFD upper displays).
The screen display resolution was very high and displayed symbols, numbers and letters were very easy to read. At least 8 different colours are used with some colours, such as blue and green, having multiple shades for things like terrain and landmark presentation. The clarity of any displayed mode and the ease of interpretation by a pilot (even from the 6”x4” half display) were superb and equal to any other modern aircraft with digital displays that I have evaluated. I also especially liked the mini ‘screen in screen’ displays (such as TCAS) that could be selected within the PFI. I also very much liked the PFI presentation of ‘highway in the sky’ flight guidance and synthetic grid ground overlay. These are very advanced and enhancing functions made even more impressive by the fact that they are part of a trainer aircraft that students will encounter from their very first training day.
Each screen has 16 line select keys (LSK and 8 per side) and 4 rotary knobs along the base (2 per side). The bottom right two rotary knobs are pushed to select either top or bottom display and turned to change values. The LSK individual select functions change depending on the display mode selected. The beauty of the Genisis Aerosystems screens was the ease by which you could go ‘back’ to correct mistakes or change values after input as it was to go ‘forward’ to complete screen set up. This may be simplistic in description but is an important training factor for students flying ‘under pressure’ in the cockpit.
I would estimate I was comfortable to configure and operate the cockpit within 60 mins of sitting in the aircraft and that was with no prior briefings or ground school.
Conclusion
The prototype Grob G120TP was impressive during my evaluation in 2010 but the 4 screen digital display production version, allied to embedded cockpit training simulation, means it has become the real 21st Century trainer aircraft that the prototype promised it would be. The aircraft now has a truly amazing training potential coupled with amazing performance and amazing value for money, all set within a ‘systems of systems’ training concept.
Additionally, in my Test Pilot opinion, the G120TP is a breakthrough aircraft featuring true ‘side by side cockpits’ (not seating) for the first time and which can now realistically span the present definitions of grading, elementary, basic and advanced lead-in phases and do so for transport, rotary or fast jet students, all at the same time, all to the same standard and all in the most cost effective manner. This offers any modern, 21st Century Air Force the chance to reshape their training organisations.
I continue to predict that the Grob 120TP will set the benchmark for 21st Century trainer aircraft worldwide, in this aircraft category.
