Although Augusta has a solid track record for making helicopters designed by other companies, the A 109 Hirundo (Swallow) was the first mass-produced helicopter actually designed by the Italian company.

The sleek A.109 was originally intended to have a single 740hp Turbomeca Astazou XII turboshaft, but for additional safety it was redesigned in 1967 around two Allison 250-C14 engines.

Development of the A 109 was protracted, but the result has been satisfying. Large corporations, police departments and military users are pleased with its solid performance. For military and naval use, the Hirundo carries dozens of combinations of electronics gear, weapons and equipment. The hi-tech maritime A 109A ECM (electronic countermeasures) variant has a radar display, direction finder, electromagnetic emission analyser and jamming equipment.

A specialised military utility model, the A 109B, was proposed, but in 1969 this was abandoned in favour of the eight-seat A 109C civil version.

R.Jackson "Helicopters. Military, Civilian, and Rescue Rotorcraft", 2005

Agusta began taking an interest in light turbine-powered helicopters in 1959 and developed a series of prototypes culminating in the A.105. Feasibility studies for a medium-capacity helicopter to succeed it — the A.109 — began in 1969, when many different designs were examined and the most promising subjected to thorough research. Wind tunnel tests, lasting almost a year, enabled the characteristics of the new helicopter to be greatly refined. Once the basic project had been drawn up, final design work of parts and equipment began in spring 1970, and in the summer detailed construction work was started.

The A.109 was originally intended to have a Turbomeca Astazou or UACL PT6B turbine engine, delivering about 700shp, but the A.109C (civil) version had the same four-blade rotor but a completely new fuselage, with clean, elegant lines. The powerplant was changed to twin 370shp Allison 250-C14 turbines and a retractable undercarriage was fitted.

The new aircraft was assembled in spring 1971; ground tests then took place, and the prototype made its first flight on 4 August 1971 from the Cascina Costa plant. It was piloted by Ottorino Lancia accompanied by Paolo Bellavita, who had developed the aircraft together with Bruno Lovera. Owing to a minor accident, testing was resumed some time later, in 1972, using the second prototype, as well as a special static test rig for the dynamic components. In 1973 a third prototype in military configuration was developed, together with a fourth model for civil use and an airframe for static tests.

The A.109 high-speed civil helicopter is in a class mid-way between the AB-206 and the Bell 212. It has a conventional configuration with a classic, four-blade articulated rotor, especially designed for fast flight. The rotor blades are of conventional honeycomb structure with a light alloy skin and extensive structural bonding. The carefully streamlined, compact fuselage consists of a broad, ventral shell in metal honeycomb with thin, light alloy panels designed to withstand the stresses from the cabin loads and shocks from the landing gear. The cabin can have various internal layouts, with pilot and crew seated side-by-side, two bench seats for two-three people, and a baggage compartment. Behind the cabin is the rear fuselage section which carries the landing gear units and fuel tanks. The retractable tricycle landing gear ensures optimum mobility on the ground and offers advantages in terms of reduced drag in fast flight. The fuel is distributed by electric pumps from two tanks with a total capacity of 550 liters. The two turbine engines are mounted side-by-side but are fully independent; breakdown of one does not affect the output of the other.

The five prototypes of the A.109 were certified in summer 1975. In fact, the Italian Aeronautical Register granted type approval to the A.109, the first twin-engine helicopter to be designed, developed and built wholly in Italy, on 30 May, shortly before the opening of the 31st Paris Aeronautical and Space Show. American approval followed two days later. In the meantime, production had already begun with five aircraft for evaluation by the Italian Army. Atlantic Aviation, then the American distributors of the Agusta 109, took out an option on 100 aircraft for the civil market at thesametime.

More recently, Agusta has introduced the Model A.109A Mk.II derivative, which has been substantially modified in the light of the flying experience of customers from 15 countries in all parts of the world. As a result engine-out performance has been improved at high altitudes, and in hot climates.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

The basic Agusta A109A is notable as the first Agusta-designed helicopter to be built in large series, and is the end product of a special market analysis initiated in 1965. Initially envisaged for commercial use only, the A 109 was designed around a single 515kW Turbomeca Astazou XII turboshaft, but mainly for additional safety considerations, was redesigned in 1967 to take two 276kW Allison 250-C14 turboshafts. The projected A 109B military utility model was abandoned in 1969 in favour of the eight-seat A 109C Hirundo (Swallow) civil version, the first of three prototypes flying on 4 August 1971. Protracted trials, minor alterations and other factors caused unforeseen delays and the first A 109 pre-production aircraft was not completed until April 1975. Delivery of production machines, designated A 109A, started in 1976.

In addition to its designated role as a light passenger transport, the A 109A can be adapted for freight-carrying, as an air ambulance or for search-and-rescue tasks. It has proved a great commercial success, especially since the uprated A 109A Mk II was introduced, this featuring uprated transmission and 298kW Allison 250-C20B turboshafts. First delivered in 1981, nearly 200 had been built by 1989, following on from the 150 or so of the original model. From 1985 the Mk II has been available in a 'wide-body' configuration with bulged fuselage sides for greater comfort.

Non-civil roles proposed for the A 109A Mk II include light attack with TOW missiles or rocket pods, aerial scout, troop carrier, electronic warfare, police work and naval missions. In addition, the helicopter can carry two Mirach RPV drones for battlefield surveillance.

More potent military versions are the A 109 EOA and A 109K. Both feature fixed undercarriage and a lengthened nose. The A 109 EOA has been ordered for the Italian army as an observation platform, powered by the Allison 250-C20R engine. The A 109K has two 538kW Turbomeca Arriel IK turboshafts for hot-and-high operations. This armed multi-role machine flew for the first time in April 1983, but no orders have been forthcoming.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

Feasibility studies of medium-capacity twin-turbine A 109 began in 1969; detailed construction started Summer 1970; first flight 4 August 1971. Five prototypes used in certification work; Italian RAI certification 30 May 1975; FAA certification 1 June 1975. Deliveries of initial A 109A started early 1976. Single-pilot IFR certification 20 January 1977 (Italy); 22 December 1977 (USA). A 109C certificated in early 1989.

First flight of A 109K April 1983; first flight of production representative second aircraft March 1984.

VERSIONS

A 109A: Initial production model, powered by twin 313kW Allison 250-C20B turboshaft engines. Replaced by A 109C Mk II from September 1981.

A 109A Mk II: Uprated version with increase in transmission rating; new tail rotor driveshaft with two-point suspension; increased tail rotor blade life and reliability through use of Nomex core material and improved bonding techniques; new self- damping engine mounts; new integral-design oil coolers and blowers; redesigned tailboom; higher-pressure hydraulic system; improved avionics and instrument layout; additional access panels; and removable floor in baggage compartment. A utility version with less sophisticated interior and instrumentation was also available from 1983.

A 109A Mk II Plus: Special law enforcement model.

A 109C: Certificated in USA by Agusta Aerospace Corporation in early 1989; approved for single-pilot IFR operation; transmission uprated from 552kW to 589kW; 'wide-body' cabin; new composites main rotor blades; Wortmann aerofoil on tail rotor; strengthened landing gear; maximum T-O weight raised to 2,720kg, affording 109kg increase in payload. Other civil/public service roles include law enforcement and coastal patrol with 360° radar.

A 109CM: Military version of civil A 109C powered by two 335.6kW Allison 250-C20R/1; can have sliding doors and fixed landing gear; ventral fin removed; first customer Belgian Army (Agusta designation 109BA) with 18 scout versions and 28 anti-tank versions designated 109HO and 109HA respectively by customer; ordered 1988; first delivery, from offset supplier Sabca, February 1992; first 109BA with equipped weight reduced to originally specified 1,944kg delivered 25 November 1992; maximum T-O weight increased to 2,850kg; this was 11th of 46 109BAs; composites sliding doors, relocated batteries and custom Collins/Alcatel Bell avionics; scouts have roof-mounted Saab Helios stabilised observation sight; anti-tank system has roof-mounted Saab/ESCO HeliTOW 2 sight and TOW-2A missiles on lateral pylons; firing trials completed in Sardinia late 1992. Last Belgian aircraft delivered 4 February 1994. Other roles for 109CM include electronic warfare, command and control, medevac, shipborne ASV/ASW and UAV launching.

A 109EOA: Italian Army scout version powered by Allison 250- C20R/1; 24 (16 EOA-1 and eight EOA-2) delivered in 1988 as Elicottero d'Osservazione Avanzata to Aviazione dell'Esercito; fitted with sliding doors, roof-mounted SFIM M334-25 daytime sight with CILAS laser ranger, variety of armament options, fixed landing gear, crashworthy fuel tanks and ECM. Maximum flight weight with slung load 2,850kg.

A 109K: Initial production model for military market. 'Hot-and- high' version of A 109A Mk II; Allison engines replaced by two 538kW Turbomeca Arriel 1K turboshaft engines; uprated transmission; new composite main-rotor head with elastomeric bearings and composite blades with hard surface coating; new tail rotor of Wortman blade section; longer nose-to-house additional avionics; and taller and non- retractable, high shock-absorbing wheeled landing gear.

Current Versions

A 109 G di F: Special version for coastal patrol, equipped with an integrated Mission Equipment Package (MEP) including various communication and navigation systems, 360° search radar RDR-1500, and searchlight, FLIR, and weapon systems such as pintle-mounted MG-3 machine gun.

A 109KM: Military version; roles include anti-tank/scout, escort, command and control, utility, ECM and SAR/medevac; fixed landing gear; sliding side doors.

A 109KN: Shipboard version with equivalent roles to A 109KM, including anti-ship, over-the-horizon surveillance and targeting and vertical replenishment.

A 109K2: Special civil rescue version first sold to Swiss REGA non-profit rescue service; REGA equipment includes Spectrolab SX16 searchlight, 200kg winch, GPS, Elbit moving map display, single-pilot IFR instrumentation; NVG compatible. Equipped with Sextant Avionique AFDS 95-1 AFCS from 1996.

A 109K2 Law Enforcement: Dedicated police version; optional equipment includes 907kg cargo hook, 204kg capacity variable speed rescue hoist with 50m of cable, rappelling kit, wire-strike protection, SX-16 searchlight, MA3 retractable light, external loudspeakers, emergency floats, GPS, FM tactical communications, weather radar, LLTV and FLIR.

A 109 LUH: Light utility version for the South African Air Force (SAAF) with Turbomeca Arrius 2K2 engines; production and final assembly by Denel. Orders placed for 30 aircraft, plus 10 options.

A 109MAX: Medevac configuration certificated in USA by Agusta Aerospace Corporation early 1989 and now installed there; large upward-opening bulged doors and fairings give 3.96m³ cabin volume and allow for two stretchers across main cabin and three sitting attendants/patients.

A 109 Power: New version based on A 109K2 airframe.

CUSTOMERS: Total of all versions delivered by 1 January 1999 was 621, of which 513 civil and 108 military.

DESIGN FEATURES: Fully articulated four-blade metal main rotor hub with tension/torsion blade attachment and elastomeric drag dampers; delta-hinged two-blade stainless steel tail rotor; manual blade folding and rotor brake optional. Tail rotor with Wortmann aerofoil and stainless steel skins; optional rotor brake on A 109K. Compared with earlier models, A 109K has lengthened cabin to hold two stretchers fore-and-aft; modified fuel system; and smaller instrument panel.

FLYING CONTROLS: Fully powered hydraulic; IFR system with autopilot available. The 109KM has three-axis stability augmentation/attitude hold system; dual redundant IFR system and four-axis AFCS with flight path computer optional.

STRUCTURE: Before introduction of composites, main and tail rotor blades were bonded aluminium alloy with Nomex core; airframe conventional all-metal; Mk II introduced self-damping engine mounts, redesigned tailboom, removable floor in baggage compartment and systems improvements.

LANDING GEAR: Retractable tricycle type, with oleo-pneumatic shock-absorber in each unit. Single mainwheels and self-centring nosewheel castoring ±45°. Hydraulic retraction, nosewheel forward, mainwheels upward into fuselage. Hydraulic emergency extension and locking. Magnaghi disc brakes on mainwheels. Non-retractable tricycle type on A 109K, giving increased clearance between fuselage and ground. All tyres are tubeless of same size (650 x 6) and pressure (5.9 bars). Tailskid under ventral fin. Emergency pop-out flotation gear and fixed snow skis optional.

POWER PLANT: Two Allison 250-C20R/1 turboshafts, each rated at 335kW for 5 minutes for T-O and 283kW maximum continuous; flat rated at 258kW for twin- engine operation; engines mounted side by side in upper rear fuselage and separated from passenger cabin and from each other by firewalls.
     Transmission ratings 589kW for take-off and 567kW for maximum continuous twin-engined operation, with maximum contingency rating of 607kW for 6 seconds. Rating for single-engined operation is 336kW for take-off (5 minutes limit).
     Two bladder fuel tanks in lower rear fuselage, combined capacity 560 litres, of which 550 litres are usable. Refuelling point in each side of fuselage, near top of each tank. Oil capacity 7.7 litres for each engine and 12 litres for transmission. Provision for internal auxiliary tank containing up to 150 litres of fuel.
     A 109K: Two Turbomeca Arriel 1K1 turboshafts, each rated at 575kW for 2.5 minutes, 550kW for take-off (30 minutes) and 471kW maximum continuous power. Engine particle separator optional. Main transmission uprated to 671kW for take-off and maximum continuous twin-engined operation; single-engine rating is 477kW for 2.5 minutes and 418kW maximum continuous. Main rotor rpm 384, tail rotor 2,085. Standard usable fuel capacity 750 litres, with optional 150 litre auxiliary tank for EMS operations, or 200 litre auxiliary tank in the A 109KM. Self-sealing fuel tanks optional. Independent fuel and oil system for each engine.

ACCOMMODATION: Crew of one or two on flight deck, with pilot seated on right. Dual controls optional. Main cabin seats up to six passengers on three forward- or rearward-facing seats in centre, plus three forward-facing seats at rear. Four/five-seat VIP layout available. Forward-opening crew door and passenger door on each side. Large space at rear of cabin for up to 150kg of baggage, with access via forward-opening door on port side. Centre row of seats removable to permit use as freight transport. Ambulance version can accommodate two stretchers, one above the other, and two medical attendants, in addition to the pilot. External freight can be transported on a centre of gravity hook. Sliding doors can be installed for rescue missions.

SYSTEMS: Two identical independent Magnaghi hydraulic systems supply dual flight servo-controls and provide emergency power in the event of engine failure. Magnaghi utility hydraulic system for activation of landing gear, wheel and rotor braking, nosewheel locking and emergency back-up. 28V DC electrical system, using two 30V 150A engine-driven starter/generators, and one 24V 13Ah Ni/Cd battery (22Ah heavy-duty battery on IFR version). Single-phase AC power at 400Hz supplied by two 115/26V 250VA solid-state static inverters; third inverter as emergency back-up on IFR version. Engine anti-icing system, using engine bleed air.
A 109KM: Electrical system supplied by two 160A 28V DC self-cooled starter/generators and 27Ah 28V Ni/Cd battery. Optional AC electrical system comprises two 250VA or two high-load 600VA 115/26V AC 400Hz static inverters. Optional high-load AC system comprises one 6 kVA alternator and one standby 250 VA solid-state inverter. Dual independent hydraulic systems for flight controls, each capable of operating main actuators in the event of failure of the other system; utility hydraulic system with normal and emergency accumulators for operation of rotor brake, wheel brakes and nosewheel centring.

AVIONICS: Standard instrumentation, plus Collins avionics for VFR or IFR operation, to customers' requirements.
A 109KM: Ergonomic, NVG-compatible flight deck with provision for IFR instrumentation and role/mission dedicated displays.
Comms: VHF/AM, VHF/FM, UHF, HF, three-station intercom, IFF and ELT.
Flight: ADF, VOR/GS/ILS, DME, GPS and VLF-Omega. Optional Collins CMS80 cockpit management system with one or more centrally mounted CDUs and automatic target handoff system compatibility.
Mission: FLIR.
Self-defence: Radar/laser warning receivers and chaff/flare/smoke dispensers.

EQUIPMENT: Depending upon mission, may include internal cargo platform, external cargo sling, externally mounted rescue hoist, first aid kit, stretchers, container for up to 980 litres of fire retardant; Spectrolab SX-16 searchlight.
A 109KM: Optional equipment includes windscreen wipers, rear view mirror, bleed air heater, particle separator, engine fire extinguisher, oxygen system, environmental control unit, one- or two-stretcher installation, air ambulance kit, external loudspeaker system, high-intensity searchlight, cargo platform, external cargo hook with maximum capacity 408kg, rescue hoist maximum capacity 91kg, snow skis and emergency floats.

ARMAMENT: A 109KM: Internal armament comprises pintle-mounted 7.62mm machine gun and 12.7mm machine gun in doorway. Provision for carriage of four or eight TOW, TOW 1, TOW 2 or TOW 2A missiles on external lateral pylons, each of 300kg maximum capacity, with roof-mounted HeliTOW sight or APX M 334 or Helios gyrostabilised sights. Alternatively pylons can accommodate 7- or 12-tube pods for 70mm or 81mm rockets; rocket/machine gun (RPM) pods each with three 70mm rockets and a 12.7mm machine gun with 200 rounds; or Machine Gun (MG) pods with 12.7mm gun (and 250 rounds) or 7.62mm gun.

Jane's Helicopter Markets and Systems

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