Update – Aeritalia/Aerospatiale ATR72

The ATR72, which is the second airliner to be developed by ATR, was conceived as early as 1981, basically as a stretch of the ATR42. The actual ATR72 program was not officially launched, however, until January 1986 following the first ATR42 delivery the previous month. Being based on an already proven airframe, development of the ATR72 was able to proceed at a reasonably fast rate, with first flight of the new aircraft taking place on 27th October, 1987. Certification of the ATR72 was recorded on 25th September, 1988 and first delivery (to Karair) took place the following month, exactly one year after first flight. Since this time the ATR72 has continued to record firm sales and already is approaching the half way point of ATR’s 20 year sales objective. The ATR72 is certainly a worthy addition to the ATR family, retaining much in the way of component commonality with its smaller stablemate on which it is based, yet with enhanced performance. The most discernable difference between the two aircraft is the addition of two fuselage plugs – 2. 19m (7ft 2in) for ward of the wing and 2. 31m (7ft ?in) aft – stretching the fuselage length by 4. 5m (14ft 10in) to 27. 17m (89ft 2in). This has increased the passenger capacity of the aircraft from the ATR42’s 42-50 seats to 64-74 seats, placing it (the company believes) in direct competition with the DHC-8-300 with a capacity of 50 seats, the Fokker 50 with up to 54 seats, and BAe’s ATP with a 64 seat capacity. This additional seating of up to 7 4 can be seen as a distinct advantage to some carriers, but perhaps only in certain situations. A 64 seat capacity ATR72, for instance, although offering less seats does provide additional baggage stowage area, important to many regional airlines – such as those in Australia – whose services often connect with international flights and whose passengers therefore often carry more than the one heavy suitcase.

To facilitate the fuselage stretch, the ATR72’s wing span has been increased from 24. 57m (80ft ?in) to 27. 05m (88ft 9ft). Wing area has been increased from 54. 5 square metres (586. 6 square feet) to 61 square metres (656. 6 square feet), though this is still relatively small and is a big factor in drag reduction. The wing incorporates composite materials in its construction, with about 30% of the wing structure – including leading edges, wing tips, ailerons, flaps and outer wing fuel tanks bf 1,500 litre (330 gallons) capacity – being built from these modern, lighter weight and cheaper materials. There is in fact a substantial weight saving of about 20% over more traditional alloy materials.

The ATR72’s engines are of a higher power rating than the smaller ATR42. The aircraft is equipped with Pratt & Whitney PW124 (2,400shp) engines with Hamilton Standard 14SF-11 props, instead of the PW120 (2. 000shp) or PW121 (2,100shp) with 14SF-5 props utilised by the ATR42. These higher performing engines have in fact helped to produce a better performing aircraft, with a maximum cruising speed of 284kts (526km/h} with an MTOW of 21,500kg (47,408Ib), compared with the PW121 powered ATR42-320’s 269kts (498krn/h). Takeoff and landing field lengths have also been considerably reduced, but maximum cruise ceiling has remained unchanged at 25,000ft ( 7,625m). The new airliner has a typical range of 1,460nm with 66 passengers plus luggage.

The interior of the ATR72 remains similar to the ATR42, with four abreast seating, toilet and galley at the rear of the aircraft, and baggage compartments at both the front and rear of the cabin. Cabin layout is quite flexible, with seating capacity ranging from a high density 7 4 seats with a somewhat tight 30 inch pitch (but with reduced baggage compartment area) down to 64 seats with 32 inch pitch. The basic version of the ATR72 allows for 66 seats with 31 inch pitch,and passenger doors at both front and rear. A similarly configured version with an extra baggage stowage compartment in place of the forward door is also offered. Overhead carry on luggage stowage compartments are standard on all aircraft, are quite spacious and more than adequate to suit the needs of most luggage carrying passengers. There is certainly no problem with head space and, needless to say,cabin noise levels remain relatively quiet for a turboprop airliner, while comfort is naturally enhanced by the pressurised cabin.

The cockpit has benefitted from new concepts successfully evaluated over the years on the ATR42 and also the Airbus A310. It is in effect very similar to the ATR42’s cockpit, though with some modifications. An ‘ergonomic’ cockpit arrangement eases crew workload,with controls placed for easy access and the cockpit display very well set out, there being no less than four cathode ray tubes (CRTs), one of which- the Advisory Display Unit-displays all autopilot data. The fully digital avionics chosen for the ATR72 provide both a saving in weight and increased reliability, while a dark cockpit philosophy enables rapid visual check of cockpit status lights out denotes normal condition. If a systems malfunction does occur, the cockpit is equipped with a colour display code associated with a Central Crew Alerting System (CCAS) to provide both visual and aural warnings for rapid response.

The ATR72 flight controls are of simple and sturdy design, and for simplified maintenance are actuated by cables and rods without servo controls. The landing gear also has been designed for relatively easy maintenance, being operated hydraulically but differing from that of the earlier ATR42 by being of lighter but stronger construction. The aircraft is equipped also with full deicing and anti-icing equipment essential for northern European and North American operations.

A freighter version of the aircraft is also available, designed to carry BB containers with a volume of 2. 8 cubic metres (99 cubic feet) each. Thirteen such containers can be carried, typically being loaded through the forward cargo door and, using built in rollers,moved into position and locked in. By far the most popular version,however,is the passenger configured airliner. Sales of the ATR72 have shown that it is an airliner suited to the needs of many airlines. Not only is it based on the already successful and proven ATR42, it offers distinct advantages over its predecessor and is well able to compete with the products of ATR’s main rivals. The airliner offers a passenger capacity perhaps only really equalled in its class by the BAe ATP, offers excellent performance and, although basically a stretched version of a slightly earlier airliner, utilises both modern construction and flight equipment. It does indeed deserve the success it is achieving.