Aviation Traders Production

Touted as a "DC-3 replacement", the aircraft was designed by Toby Heal, and featured his patented ‘tensioned skin’ system of construction, which required that the aircraft’s fuselage had to be designed so that its outer skin curved in two directions at once, both around its circumference and along its length. However, the tension skin concept was dropped in favour of an unstressed skin conventionally riveted to the aircraft’s frames and stringers, though by then the Accountant had been decisively shaped by Heal’s tension skin system, thus ensuring that the aircraft had all the disadvantages of the system and none of the advantages. The wing structure, on the other hand, was a conventional two spar, all metal structure in five sections, with slotted flaps, plus a single slotted flap below the fuselage. The tailplane, like the wing, was a two spar all metal structure. The main undercarriage units retracted into fairings below the engine nacelle, while the nosewheel was semi-recessed into the fuselage and covered by an external fairing. Accommodation was provided for a crew of three, with passenger accomodation for thirty in normal configuration. Two 1.740 e.h.p Rolls Royce Dart 512 turboprop powerplants, mounted above the wing.

ATL.90 Accountant Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
82 ft 6 in	62 ft 1 in	25 ft 3 in	632 sq ft	16961 lb	32000 lb		295 mph/ 256 kn	2070 mi
25.15 m	18.92 m	7.7 m	58.71 m2	7693 kg	14515 kg		475 km/h	3331 km

Car ferry conversion of Douglas C-54/DC-4 with a capacity generally of 22 passengers in a rear cabin, and five cars loaded in at the front. Aircraft for Aer Lingus were quickly convertible between 55 seats and 22 seats with five cars. Some aircraft were pure freighters with only nine seats. One aircraft had 55 high-density seats and room for three cars. The conversion entailed replacing the forward fuselage with a new all metal semi monocoque structure 8 feet 8 inches longer, with a raised flightdeck in a bulbous "hump" to allow a hydraulically operated sideways hinging nose door. It also entailed more powerful wheel brakes and an enlarged tail of completely new design, with metal covered fin and fabric covered rudder. The nosewheel was semi-recessed into the fuselage and covered by an external fairing. The original four 1.450 h.p. Pratt and Whitney Twin Wasp R-20000-7M2 powerplants were retained.
The ATL.98A incorporated design modification ATL 98/5150, calling for the addition of 250 pounds of lead weights added to each wing tip. This modification increased the maximum zero fuel weight (MZFW) by 1000 pounds as the wing load was more evenly distributed across the wing, reducing flex and stress at the wing root effectively increasing cargo payload.

ATL.98 Carvair Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
117 ft 6 in	102 ft 7 in	29 ft 10 in	1462 sq ft	41365 lb	73800 lb	207 mph/ 180 kn	250 mph/ 217 kn	2300 mi	17000 ft
35.81 m	31.27 m	9.09 m	135.82 m2	18763 kg	33475 kg	333 km/h	402 km/h	3701 km	5182 m