ATR 72-600 - Easy to Fly

Enter the new flight deck of the ATR 72-600 and you are impressed by the neat, uncluttered, modern deck with avionics from Thales. Everything seems to be in place, with only a few knobs and switches on the panels.

Stiffening competition and rising fuel prices have had one effect—the shift in focus from jet airplanes to turboprop aircraft for short haul operations. Essentially, turboprops are airplanes with small jet engines and large external propellers, making the combination aerodynamically very efficient at low operating speeds.

The growing value and economical importance of turboprops is well reflected in changing the market trends. The popular ATR 72 was introduced in 1989 and up to the end of 2011, the company sold 552 airplanes in four major variants. Surprisingly, the ATR 72-600, a newly launched version of the ATR 72, is not accepted by the European Aviation Safety Agency (EASA) as a new variant or model. However, the company sold a whooping 265 airplanes since it was launched in 2007, taking the total sales of this popular turboprop model to 817. Another market shift has been in leasing companies engaging in “speculative buys”; purchasing sizeable numbers of ATR 72-600 with not necessarily a customer line up, driven by the immense and promising market value of this airplane.

Ten years after the ATR 72-500 was introduced in 1997, ATR decided to modernise the ATR 72, the biggest upgrade being the new avionics suite (NAS). Operationally, this translates to reduced crew workload, improved situational awareness, enhanced safety and potentially greater fuel savings through improved navigation capabilities. Technically, the NAS promises greater avionics system reliability, flexibility and reduction in weight.

New Avionics Suite

Enter the new flight deck of the ATR 72-600 and you are impressed by the neat, uncluttered, modern deck with avionics from Thales. Everything seems to be in place, with only a few knobs and switches on the panels.

Avionics on the new ATR 72-600 are derived from that developed for the Airbus A380 aircraft. It is the only turboprop utilising the concept of integrated modular avionics, with equipment connected through an Avionics Full DupleX (AFDX) network, offering redundancy and high speed performance. The NAS reduces parts count by 30 per cent, resulting in weight savings of 30 kg and maintenance cost saving of about 15 per cent.

For the ATR 72, the NAS is a “two-generation leap in technology”. Barring two sets of bulky cathode ray tube based electronic attitude and direction indicators (EADI) and electronic horizontal situation indicators (EHSI), almost all the instruments in the older variants of the ATR 72 are electro-mechanical.

In the ATR 72-600, about 32 Honeywell and Collins instruments on the front panel have been replaced by just five 10-inch LCD displays. Of these, two primary flight displays (PFD) for the pilots replace the primary flight and navigation instruments associated with the respective sides. A third, centrally located engine and earning display (EWD) replaces engine, fuel, hydraulic and pressurisation gauges, while also replacing the bulb-based crew altering panel. Two additional screens located next to the PFDs serve as the multi-function display (MFD). The solid-state nature of the instruments and their digitisation ensures greater reliability, improved display accuracy and significant flexibility.

The advantages with the screens are multi-fold. There is now a new dimension to the same information presented—colours. This grabs the attention of the crew much faster to the specific problem on the specific sub-system by the use of appropriate colours. The LCD screens allow for almost anything to be displayed, which is how crew workload and safety are improved. Flight guidance modes are displayed as flight mode annunciators on the PFD itself, rather than being remotely-displayed on the glare shield as before. Speed targets are automatically set by the flight management system, while speed trends, limits and margins are pictorially displayed, increasing the crew’s awareness of the aircraft’s flight envelope under the prevailing conditions of flight. Even a mini navigation display is always visible at the bottom of PFD.

The MFD normally displays the lateral profile of the aircraft’s flight path with other information such as terrain, traffic, weather and radio aids overlaid on the display with respect to the aircraft’s position and heading. The display is larger, clearer, is colourcoded for active legs and more importantly, even for displays constraints associated with waypoints en route.

Apart from this, the MFD also displays the tuned navigation radio frequencies, communication radio frequencies, while also displaying every system (cabin, electric, hydraulic and engine) and its associated synoptic. This allows the crew to not only pinpoint faults, but also to better understand the secondary effects of faults or failures which automatically display the concerned system synoptic on the MFDs of both pilots.

Checklists, both normal and emergency, feature below the engine instrument synoptic on the EWD LCD screen. These are also colour-coded, facilitating identification of fault and presenting the checklist appropriate to the situation. The advanced flight management system now supports more features for the automation of navigation and performance, although vertical navigation still remains advisory. A standard dual global navigation satellite system (GNSS) onboard the airplane adds redundancy.

Three analogue standby instruments are replaced by one LCD-based integrated electronic standby instrument (IESI). Apart from displaying the attitude, speed and altitude, the IESI can also allow for the tuning of a navigation frequency for instrument landing system (ILS) guidance.

All the necessary and commonly referred to functions are now displayed in the primary scan area of the pilots. Very rarely does a pilot flying the ATR 72 with the NAS have to look down or up to scan flying instruments. Primary flight instruments, navigation data, system information, checklists, guidance modes are all available on the five robust, reliable and functionally flexible LCD displays. The aggregation and integration of all necessary information into a narrow, defined field of view, improves the pilot’s situational awareness while significantly increasing flight safety through minimised distraction.