This story, by Keith Robey, appeared in Aircraft for July, 1959.

Notes and flying impressions of DCA's recently acquired aircraft. By KEITH ROBEY

The Aero Commander made its first appearance on the Australian register in May when two Model 560E Aero Commanders arrived in Australia for use by the Department of Civil Aviation. The two aircraft were delivered by air from the United States and flew via the North Atlantic, Europe and the Middle East to avoid the long overwater stages of the Pacific crossing.

Flown by DCA crews the Aero Commanders left Oklahoma on April 17 and the 16,184 nautical mile journey was completed in 106 flying hours in 31 days elapsed time. The DCA ferrying party comprised A. H. Spooner (leader), E. C. Sims, L. P. Bond and I. T. Perry. The route followed by the two aircraft was Oklahoma City, Nashville, Washington, Montreal, Seven Islands, Frobisher, Cape Dyer, Sondrestrom, Keflavik, Prestwick, Gatwick, Marseilles, Rome, Athens, Beirut, Bahrein Is., Karachi, New Delhi, Calcutta, Bangkok, Singapore, Jakarta, Denpasar, Darwin, Alice Springs, Broken Hill, Melbourne. The flight was completely free from mechanical trouble of any kind. The oil was changed at Gatwick, the filters cleaned at Singapore and upon arrival at Darwin a slight leak which had developed in an oil line on one aircraft was overcome by tightening a pipeline union. Other than these very minor servicing operations only daily maintenance checks were carried out en route.

The Aero Commanders cruised throughout at an average 156k-160k TAS at 8500 ft. and fuel consumption for stages of less than four hours averaged 25.5 (U.S.) gal ./hr. For those stages in excess of four hours the consumption rate dropped to approximately 23 (U.S.) gal./hr. which gave an ultimate endurance of 9 ½ hours.

The DCA ferry crews speak highly of the performance of the Aero Commanders throughout the long ferry flight where extremes of both cold and hot climates were experienced. It was found that in the tropical regions a better climb performance was obtained by climbing at 3000 rpm instead of the quoted 2750 rpm and at an indicated airspeed of 125-128k instead of the recommended 135-140k, but otherwise recommended speeds and power settings were used throughout. The aircraft were not fitted with de-icing equipment and caution was exercised when flying in icing conditions. The only two delays en route were occasioned by weather at Frobisher and deteriorating conditions on the run to Sondrestrom which caused an unscheduled landing at Cape Dyer.

The Aero Commander Model 560E is a twin-engined high wing monoplane equipped with a retractable tricycle undercarriage. It is powered by 295 hp six cylinder horizontally opposed Lycoming engines and carries up to seven persons over distances of up to 1600 miles at cruising speeds in excess of 200 mph. It can be truly described as a miniature airliner and as an executive transport offers standards of passenger comfort and performance seldom associated with a small aircraft. The Aero Commander has proven very popular in the executive field in the United States and a large number of these aircraft are at present in use by leading American Corporations and business houses. Over 650 Aero Commanders are in service in various parts of the world. The Aero Commander is manufactured by the Aero Design and Engineering Corporation of Bethany, Oklahoma. This company was formed in October 1950 to manufacture the Aero Commander and the first model 520 received its approved type certificate in January 1952. The first production model 520 was delivered in February 1952 and after a total of 150 model 520s were built, production began of an improved model 560. Four versions of the Aero Commander are current y in production, all these models having a common fuselage with the same cabin and seating configuration. The model at the lower end of the price range is the model 500, powered by two Lycoming 250 hp engines. The 500 carries less fuel than the other models, and its speed and payload are also reduced. The model 680E is powered by two supercharged Lycoming 340 hp engines and has much the same range as the 560E at an increased airspeed and 1000 lb. greater payload. The 720 Alti Cruiser is a pressurised version of the 680E.

The Aero Commander 560E is of all metal construction throughout, the fuselage is a metal skinned semi monocoque structure and the mainplane is fabricated in three sections with the centre section integral with the fuselage. The wings, flaps, ailerons and all other control surfaces are metal skinned. The wing section is a modified NACA 23012 section and aspect ratio is 8.2. The rectractable tricycle undercarriage is equipped with an air-oil shock absorber system and Goodyear disc type hydraulic brakes, both undercarriage and flaps are hydraulically operated. The 295 hp Lycoming GO-480-G1B6 engines drive Hartzell three blade fully feathering constant speed propellers and both engines are equipped with generators and engine driven fuel pumps.

Fuel capacity of the 560E is a total of 223 U.S. gallons carried in the wings in bag type tanks. There are two separate systems known as the primary system consisting of two centre section tanks with a total capacity of 156 gallons and the secondary system with a further 67 gallons carried in tanks in the outboard wing panels. In addition to the dual engine driven fuel pumps the fuel system incorporates two auxiliary electric fuel pumps.

The high wing configuration of the Aero Commander makes entry to the passenger cabin a simple matter, a most important consideration in an executive aircraft. The low slung fuselage is close to the ground and the passenger cabin door, which is situated towards the rear of the cabin on the port side, may be entered without the assistance of steps of any kind. The bottom of the door is only 20 inches above ground level. The DCA Aero Commanders feature an attractive blue-grey cabin trim and are fitted out as standard seven seaters. There is no dividing bulkhead between the cockpit and cabin proper and seating arrangements comprise two pilots' seats with two separate seats behind and a bench type rear seat accommodating three at the rear of the passenger cabin.

Handling Impressions

My flight in the Aero Commander was from Melbourne Airport and I flew with Airways Surveyor Eric Sims, one of the DCA pilots who ferried the Commanders from the States. After walking around the aeroplane and checking the various items listed in the preflight inspection we entered the cabin with no more effort than that required to board a modern sedan car and seated ourselves in the very comfortable pilots' seats. The rudder pedals are fixed, but the seats are adjustable and there is ample legroom for long legged pilots such as myself. As the control columns are located at the sides of the cockpit with the control wheels mounted on extension arms the cockpit floor is unobstructed and entry or exit from either pilot's seat can be achieved quickly and without any of the usual contortions associated with such actions.

Starting up procedure calls for first checking that the parking brake is on, this is applied by depressing both toe brake pedals in the usual manner and then pulling out the parking brake control on the central pedestal, the undercarriage safety lock should be engaged and the battery and generator switches on. The Aero Commander is equipped with electrically operated fuel valves in place of conventional fuel cocks and the switches to operate these valves are located on the electrical panel above the windscreen. This system requires electrical power to be available in order to change tanks. The desirability of such a system is, I feel, open to question although, no doubt, the possibility of a complete electrical failure in such a well equipped aeroplane as the Aero Commander is very remote. A priming pump is provided, but priming is unnecessary for a warm start. The electric booster pumps should be on and with the throttle set approximately 1/8 in. open and the magneto switches on "both" the engine is ready to be turned over on the electric starter. As the engine fires the mixture control should be moved forward out of idle cut off position and the throttle adjusted to idle at approximately 1000 revs. As both engines are equipped with hydraulic pumps and generators starting order does not appear to be important.

After starting up we called the tower for taxy instructions and proceeded to taxy out. Visibility from the cockpit of the Aero Commander whilst taxying is of the highest standard, the wing tips are clearly visible and the aircraft rides extremely well with a minimum of pitching movement. One's first impression is that of being unusually close to the ground, but this is not unpleasant nor disconcerting in any way. Eric Sims taxied out at Essendon and carried out the first takeoff, our agreed upon plan being to fly across to Bacchus Marsh aerodrome where I would do some upper airwork and general handling before carrying out some circuits and landings. I subsequently found at Bacchus Marsh that while the Aero commander is in no way difficult to taxy the technique is slightly different in that the Aero Commander is equipped with a power operated steerable nosewheel and nosewheel steering is activated through the toe brake pedals rather than the rudder pedals. The first pressure on the toe brake pedal steers the nose wheel and a further pressure applies the brake. The art is easily mastered and taxying presents no problem. Left to its own resources the Aero Commander shows no inclination to do anything except keep rolling straight ahead.

Arriving at the holding point we ran the engines in turn up to 1500 revs to exercise the propellers and then to 2200 revs for a magneto check. Pre-takeoff drill calls for mixtures rich, pitch fully fine, undercarriage lock off, fuel selector valves on centre tank, electric booster pumps on and flaps set at the quarter extended position.

Eric Sims’ takeoff from Melbourne Airport was most impressive. The fuel load was light and only two up, but the aircraft had been ballasted up to its maximum all up weight of 6500 lb. and performance was truly representative of full load operation, acceleration on takeoff was rapid and the climb away steep. Rate of climb appeared to be in the vicinity of 1200-1400 ft./min. Once clear of the Melbourne circuit I took over control and on the short flight to Bacchus Marsh settled down to get the feel of the Aero Commander. Visibility in flight in all important directions is excellent and noise and vibration levels low, all three controls are effective, positive and well harmonised, but when judged by light aircraft standards, stick forces are a little high. Cruising at 2000 ft. using a power setting of 22 in. x 2500 revs the Aero Commander at first indicated 148k, but this speed slowly built up over a period of six or eight minutes and finally settled down to 155k. Outside air temperature at the time is was plus 8 deg. C, but as position error at this speed is -4k TAS remains approximately 155k. The Aero Commander’s mander's cruise performance improves, of course, with altitude and at 10,000 ft. using 70% rated power the handbook quotes a cruising speed of just over 180k. No opportunity existed on this flight to check high level cruise performance, but the DCA-pilots who have flown the Commander state that the performance figures in the handbook are accurate.

Arriving in the Bacchus Marsh area we climbed to 3000 ft. and after experimenting with some turns and general handling set out to explore the stalling characteristics of the Aero Commander. With power off and flaps up the nose has to be held quite high in order to wash the speed back and I found that the stall occurred at an IAS of 65k. There was some slight aerodynamic warning of the approach of the stall and an electric stall warning device sounds off some 10k before stalling speed is reached. With power off and undercarriage up the stall warning buzzer is a little difficult to hear above the clamor of the undercarriage warning horn. The stall when it occurred was quite docile and resulted in a dropped port wing, normal recovery action resulting in full control being regained with a loss of approximately 300 ft. Aileron control remained effective down to the point of stall. With undercarriage down, full flap and no power the stall was delayed down to 57k, the port wing dropping a little more sharply this time and recovery taking a little longer.

Single engine performance of the Aero Commander is most impressive. Cruising at 150k at 3000 ft. I found that feathering the port engine resulted in only a slight yaw which was easily checked with moderate pressure on the rudder, and with the rudder trim adjusted to correct for the yaw we cruised comfortably at 120k using only 70% power on the good engine. Control was most effective and I found that turns into or away from the dead engine could be effected with adequate control and no loss of height.

After unfeathering the port engine we descended to circuit height and Eric Sims carried out the first approach and landed onto Bacchus Marsh strip to show me how it should be done. Upon trying my own hand at some circuits and landings I found that the Aero Commander is a very docile aircraft to handle in the circuit. There is practically no swing on takeoff, acceleration is rapid and the nosewheel should be lifted off the ground at 60k. A firm backward pressure on the wheel will lift the Commander off the ground at 85k and the initial climb is made at 105k. After the undercarriage is retracted the revs are brought back to 3000 and the flaps pulled up before a further reduction in power is made by bringing the revs back to 2750; the climb is then continued at 130k. The initial angle of climb is steep and I felt reluctant to pull the nose up high enough to keep the climbing speed at the recommended figure. On the downwind leg, speed should be reduced to 140k before the undercarriage is lowered and after it is lowered the safety lock should be engaged. Half flap is lowered at 130k and the remainder of the circuit is flown at 100k. Turning final, electric booster pumps should be on, pitch fully fine and full flap lowered when ready. With speed back to 90k on final the Aero Commander descends at a comfortable angle and as the threshold of the runway is crossed the power is pulled off as the wheel is brought back and the aircraft sinks gently onto the runway with little float. Once on the ground a determined pull on the wheel is necessary to hold the nosewheel off until elevator control is lost. Landing distance over a 50 ft. obstacle at sea level is 1500 ft. and this distance exceeds by 8 ft. the distance required on takeoff at sea level to clear a 50 ft. obstacle.

After two or three circuits I began to feel quite at home in the Aero Commander and thoroughly enjoyed the experience. With the exception of the location of the flap and undercarriage indicators which are installed on the extreme right hand side of the instrument panel and, therefore, a little difficult to see from the left hand seat I thought that cockpit and instrument layouts were particularly good with all important controls and instruments ready to hand and easy to locate. One pilot operation should present no difficulty.

The time finally came to return to Melbourne Airport and upon our last takeoff from Bacchus Marsh Eric Sims demonstrated an engine failure just after takeoff. Decision speed is 75k and once this speed has been reached the takeoff may be continued on one engine. Simulating an engine failure at 80k we feathered the port engine and climbed away at an indicated airspeed of 90k-95k using full throttle and 3000 revs on the starboard engine. Rate of climb was approximately 400 ft./min., a creditable performance for any light twin.

After another landing back at Melbourne Aiport I reluctantly parted company with this very nice aeroplane. DCA will use their Aero Commanders for communications duties and they will replace Anson aircraft now being discarded as obsolete. As there are more than two Ansons to replace it is possible that further orders might follow, with eventually one aircraft of this or a similar type based in each region.

The Aero Commander has much to offer as an Executive or VIP aircraft and there is little doubt that we will see more of it in Australia in this role. Apart from its excellent performance, ease of access to the cabin and the fact that the passengers and crew may change seats in flight make the Aero Commander an attractive proposition for executive use. Unfortunately, the price for such convenience is high. The Australian agents for the Aero Commander, E. L. Heymanson & Co. Pty. Ltd., quote the price of the standard 560E as $78,400 flyaway Oklahoma.

AERO COMMANDER 560E - LEADING PARTICULARS

High speed-rated power S/L, 222 mph; Cruising speed-70% rated power at 10,000 ft., 210 mph; Stall speed-gear and flaps down-power off, 66 mph; Stall speed-gear and flaps up-power off, 74 mph; Gross weight, 6500 lb.; Empty weight, 4300 lb.; Range-with 30 min. reserve at 10,000 ft. at 55% rated power, 1625 miles; Fuel capacity, total usable, 223 gal.; Service ceiling-2 engines, 22,500 ft.; Single engine ceiling-feathered prop., 8000 ft.; Rate of climb-2 engines-S/L, 1450 ft./min.; Rate of climb-1 engine-S/L, 300 ft./min.; Takeoff distance to clear 50. ft obstacle at S/L, 1452 ft.; Landing distance over 50 ft. obstacle at S/L, 1500 ft.
All performance is based on full gross weight and standard atmospheric conditions, unless otherwise stated.
DIMENSIONS: Height, 14 ft. 6 in.; Length, 35 ft. 1 ¼ in.; Span, 49.56 ft.; Track, 12 ft. 11 in.

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