M577 command post carrier

The M577 command post carrier, also known as the M577 command post vehicle or armored command post vehicle, is a variant of the M113 armored personnel carrier that was developed and produced by the FMC Corporation to function on the battlefield as a mobile command post i.e. a tactical operations centre, usually at the battalion level. In U.S. military service its official designation is Carrier, Command Post, Light Tracked M577.
Introduced to the U.S. Army in 1962 it soon saw operational service in the Vietnam War and more recently in the 2003 invasion of Iraq. It is used by many armies around the world and has been adapted for further uses such as an armored ambulance, emergency medical treatment vehicle and fire control vehicle. It is also used by various police forces and law enforcement agencies as a tactical response vehicle.
The M577 is easily distinguished from the M113 upon which it is based by its raised upper hull and roof-mounted auxiliary power unit (APU). Vehicles are generally unarmed.
The experience gained by the U.S. Army in the Second World War showed that close co-operation between infantry and armored forces is a necessity for combined-arms mechanized mobile warfare. Mobile warfare increases both the scope and size of the theatre of operations, and mobile command and control posts are necessary to co-ordinate operations at the divisional, brigade and battalion levels.
Whereas tanks and armored cars offered a level of protection against weapons fire, they usually did not provide sufficient internal room to permit the extra personnel needed to operate all the radio sets. Lightly or unarmed vehicles could be used to transport temporary structures (e.g. tents) that gave greater work space, but these structures lacked protection from direct and indirect weapons fire, and advancing front line units could exceed the communication range the command post, necessitating the dismantling and removal of the structure to a new location. Experience gained in the snow and mud in the Korean War showed the advantage of tracked over wheeled vehicles.
In 1960, no such vehicle existed in the U.S. Army inventory that was able to satisfy all of these requirements.
The first four prototypes were built in February 1962 by United Defense Industries at the U.S. Army's Detroit Arsenal. They were designated the XM577, and were conversions of M113 APCs. Upon completion in March 1962 the first vehicle was shipped to the Aberdeen Proving Ground for engineering tests, while the remaining three vehicles were shipped to the Armour, Infantry and Artillery Boards for evaluation tests.
The results of all tests were generally positive, and the vehicle went into immediate production. The first batch of 270 vehicles were accepted into U.S. Army service between in December 1962 and March 1963. In March 1963 under Standard A Acceptance the XM577 was redesignated as the M577, indicating official status as a regular production vehicle. Production began on a second batch of 674 vehicles in November 1963, all of which entered service by the middle of 1964.
The M577 shares the chassis, lower hull and running gear from the M113 upon which it is based. The hull sides from the engine firewall to the rear cargo ramp were extended by 25.25 in (64 cm) for a maximum headroom in the rear compartment of 74.75 in (190 cm), allowing operators to perform duties standing up. On the roof, the commander's cupola of the M113 APC has been replaced with circular hatch similar to the driver's hatch, and the large rectangular hatch over the troop compartment was removed. There is no external weapons stations fitted to the M577, although most vehicles were fitted with an internal rifle rack.
Mounted to the front of the raised upper hull, centrally located to the right of the driver's hatch, is a 4.2 kW 28V 150A gasoline auxiliary power unit generator, that provides power to the M577/M1068's auxiliary equipment, dependent upon variant as specified below, without the vehicle's main engine running. The unit can be used to power two vehicles, and can be removed from its mounting basket using a lifting davit located on the vehicle's roof and operated from within or alongside the vehicle using a 50 ft (15.24 m) extension cable.
As part of the A3 upgrade, a more powerful 5.0 kW unit was fitted. Unlike the previous gasoline-fuelled unit, the new unit operates on diesel fuel, providing more hours of operation on an equivalent fuel load.
The single 80 gallon internal fuel tank of the M113, located at the rear left, is replaced by two 60 gallon tanks, located each side near the rear, providing a greater operating range than a M113. They also serve as the base for fold-out tables. Radios are usually fitted along the left wall, as well as the front of the right wall. Map boards are usually fitted along the walls, along with additional storage facilities for maps and code books etc.
Overhead dome lights were fitted within the rear compartment. A personal heater is located at the front right of the compartment, which serves as an equipment heater in Arctic and winter operations.
A 5-man bench seat could be fitted to either or both sides of the rear compartment, although in some vehicles no seating was fitted whatsoever. The rearward-facing seat on the commander's station was removed. For the M1068, inward-facing individual seats for two operators replaced the bench seat. Further folding tables and chairs are often carried, stowed while the vehicle is in transit.
Equipment fitted within the rear compartment of the M577/M1068 varies according to the vehicle's purpose.
Vehicles are equipped with additional radio sets as found in a standard M113 APC, to provide command and control facilities across the unit (e.g. battalion) and coordinate with other units and higher levels of command (e.g. regimental HQ). Removable antenna masts are usually carried and attached to the vehicle's roof.
In U.S. Army service, each vehicle usually carries three of four different communications suites (radio sets), each providing a specific communication network according to the communications roles they were assigned e.g. to divisional headquarters, across all vehicles within the unit (battalion), etc. The suites operated over amplitude modulation (AM), continuous wave (CW) and frequency modulation (FM), with the frequencies and number of channels, and transmission and reception range determined by the set. Communication suites were originally analogue, but with the introduction of the M577A3 and A4, have mostly been upgraded to digital. Analogue radio sets fitted to the M577 in U.S. service include:
It must be recognized that there was no such thing as a standardized M577 medical vehicle. Vehicles were configured according to the country operating them and internal configuration and equipment varied accordingly, which was also defined as to whether they were used as an emergency evacuation (ambulance) or treatment vehicles.
In U.S. service it appears that M577s were only used as emergency evacuation vehicles very early in their operation careers, i.e. in the early years of the Vietnam War. This role was soon provided solely by M113 "armored ambulances", and the M577 was then only used as emergency treatment vehicles (e.g. battalion aid stations).
When configured as an ambulance, compared to a M113 which could be fitted with up to four litters, the extra room inside the M577 allowed it to carry two additional litters i.e. up to a maximum of six.
Vehicles configured for other roles were configured with specialized equipment accordingly e.g. M577 Fire Control Vehicles were often fitted with TACFIRE artillery control consoles.
A tent extension attaches to the rear of the vehicle above and around the rear cargo ramp, increasing the workspace available to operators, and in the case of the emergency treatment vehicles, to function as a field dressing station or hospital. The tent is erected over collapsible steel tubing, which is carried in brackets on the rear of the vehicle. The tent can be connected to up to four vehicles parked in a cross, to provide a common work area.
With the introduction of the M1068 SICPS Carrier, the M577-specific tent was replaced with a Modular Command Post System (MCPS) tent, which attaches to the rear of the vehicle by a "bootwall" that covers the rear of the vehicle but still has an entrance to the vehicle's interior. The MCPS tent has the advantage of being quicker and easier to erect and dismantle, provides overhead lighting and power sockets for electrical equipment, and the modular design of MCPS allows more tents to be easily connected.
Ownership of title for and production of the M577 has changed many times over the vehicle's history due to corporate buy-outs and take-overs. Originally produced by FMC's combat vehicles division United Defense Industries (UDI), in 1995 UDI was purchased by Harsco Corporation to become United Defense (UD). In 2005 UD was then purchased by BAE Systems (BAE). As of February 2020, the M577 is within the company's Global Combat Systems Ground Vehicles portfolio of current products in the subsidiary BAE Systems Platforms & Services.
The M577 is produced or remanufactured locally in several countries under licence from or in partnership with BAE. This includes:
In total, more than 7,300 vehicles have been built, of which around 3,900 were M577A1, making the M577 the most numerous single variant of the M113 family after the APC.
The M577 has followed a similar upgrade path to the M113 upon which it is based, resulting in the following basic versions:
The original version based upon the M113 chassis. Specifications and performance are as follows:
The initial upgraded version based upon the M113A1, introduced in 1964. The gasoline engine was replaced with a more powerful diesel engine, providing better fuel economy and a greater operating range, as well as the reducing the fire hazard of gasoline fuel. Specifications and performance are as follows:
In 1979, further upgrades were introduced based on the M113A2. Engine cooling was improved by switching the locations of the fan and radiator. Higher-strength torsion bars increased ground clearance, and shock absorbers reduced the effects of ground strikes. Increased weight affected the vehicle's freeboard when afloat, and it was no longer required to be amphibious. Four-tube smoke grenade launchers were added on each side of the trimvane on the front of the vehicle.
Specifications and performance are as follows:
In 1987, further improvements were introduced based upon the Reliability Improved Selected Equipment (RISE) package fitted to the M113A3. This included a yoke for steering instead of laterals (tillers), a more powerful turbocharged engine with a larger alternator increasing output from 100A to 200A, and internal spall liners for improved fragmentation protection for occupants. Weight increased again, and some vehicles were fitted with the larger trimvane from the M113A3 to offset the freeboard issues first encountered with the M577A2.
Specifications and performance are as follows:
The A4 is the next generation modernized version of the M577 command post vehicle production version developed by BAE Systems and in partnership with FNSS. Fitted with upgraded digital systems and communications suites, applique armor and external armored fuel tanks similar to those fitted to the M113A3 on both sides of the rear ramp, freeing up more internal space. An improved version of the 6V53T turbo-diesel engine with power increased to 350 hp (261 kW) is installed, along with an improved '4B' version of the TX-400 automatic transmission. The new vehicle has a maximum capacity of seven personnel: driver, vehicle commander and up to five staff officers or system operators, and can be configured as a Fire Direction Centre Vehicle. Limited in numbers and used as the basis for the M577A4 armored treatment vehicle.
Like the M113 upon which it is based, there are many variants of the M577 in service, many specific to a particular country's army.
In 1965 the Australian Army purchased 58 M577A1s in 1965 with some vehicles immediately shipped to Vietnam for operational duty with the 1st APC Troop. Operational experience with the M113A1 showed that vehicles of this family were vulnerable to hull damage from enemy mines, and an indigenous armor upgrade kit was soon developed and fitted to all vehicles. The upgraded armor consisted of a folded aluminum plate installed under each sponson for the first three road wheels on each side of the vehicle. In 1970, a further 38 mm of aluminum armor was fitted along the entire bottom of the hull, which greatly reduced crew and passenger casualties even from large mines. This armor upgrade package was subsequently fitted to all M577s (and other M113 vehicles) purchased to replace those lost during the war.
In Australian service the M577A1 ACV was originally fitted with both U.S. and British radio sets, reflecting the dual origins of their pieces of major equipment. Vehicles would normally carry up to five sets e.g. three AN/GRC-125, one AN/VRC-49 and one AN/GRC-106. AS-1729/VRC antennae were mounted on the vehicle's roof, and an RC-292 antenna could be set up outside the vehicle when it was static to provided significantly more range for the vehicle's radios.
Commencing in 2002 as part of the Land 106 program, the M113 major upgrade project saw 43 M577A1 ACVs upgraded to local AS3 standard and redesignated as the M113AS3 ACV. The upgrade package consisted of:
The Australian Army also operated a number of M577A1 armored ambulances, which effectively serve as both emergency treatment and evacuation vehicles. As part of the M113 major upgrade project, 15 of these vehicles were converted to a similar AS3 standard as the ACV and redesignated as the M113AS3 armored ambulance.
Based on the M577A3 command post vehicle, 23 vehicles were in service with the Canadian Army. Nicknamed the 'Queen Mary', the vehicle is equipped with an upgraded communications suite. Externally, additional stowages are mounted on the vehicle's roof, along with removable antenna masts. At the front of the vehicle a stowage basket is attached to the engine cover in place of the trim vane, and cable cutters were mounted at each side. A transparent perspex shield was often fitted in front of the driver's hatch for Arctic operations. Snow hawsers and spiked "ice cleats" were carried on external mountings. From 2001, the Diehl 213G steel tracks were replaced by Soucy rubber band tracks for quieter operation on roads and better operation on snow and ice.
In German service, the M577 and M577A1 received different fire extinguishing and heating systems, modified periscopes and SEM 25/30 radios, and were known as the M577G and M577GA1 Gefechtsstandspanzer(GefStdPz) . In the late 1980s M577GA1s were upgraded to A2 standard and were designated M577GA2. These vehicles operated in four different roles:
Vehicles received further upgrades under the Nutzungsdauerverlängerung (NDV) program consisting of:
The M112GA2 is distinguished from U.S. and other NATO M577s stationed in Germany by the following external features:
Israeli designation of the M577 command post carrier. Vehicles are equipped with external stowages and storage racks along the hull sides, similar to those seen on IDF M579 Fitter's vehicles.
The NM196 Hjelpeplasspanservogn was the medical treatment version of M577A2. This vehicle saw the following upgrades during its service life:
The NM198 Kommandopanservogn was the local variant of the M577A2 command post vehicle. This vehicle saw the following upgrade(s) during its service life:
Developed in the 1980s, the K277 is a locally produced version of the M577A1 command post vehicle featuring a different engine and transmission – a MAN D2848T V8 diesel engine made under licence by Doosan and Allison X200-5K automatic transmission. The upper and lower hull of the vehicle is fitted with a layer of spaced laminate steel armor similar to that fitted to the K200 IFV which provides increased ballistic protection as well as extra buoyancy. The front of the vehicle is fitted with the armored trim vane from the K2000. Vehicles are usually armed with a Browning M2 HB 12.7mm heavy machine gun. The K277A1 is an upgraded version with a more powerful engine and transmission, NBC protection and an automatic fire extinguishing system. With the additional armor and other changes, the K277 is heavier than the M577.
Commencing service with the Republic of China Army in 1982, the CM-26 command track is a locally built variant based upon the M577A2 that shares key components from the CM-21A1 armored infantry fighting vehicle. Unlike the CM-21A1, which varies extensively (it resembles the armored infantry fighting vehicle (AIFV)) from the M113A2 upon which it is based, changes to the CM-26 are mostly limited to its engine and transmission. The vehicle is fitted with a 248 hp (185 kW) Perkins TV8.640 turbo-diesel which provides significantly more power than the 212 hp (158 kW) of the Detroit Diesel 6V-53 fitted to the M113A2/M577A12. The engine is coupled to a locally built automatic transmission developed by Taiwans' Industrial Technology Research Institute and is similar to the Allison TX-200-1 fitted to the M113A1/M577A1 and features four forward and one reverse gears. The vehicle is also fitted with night vision driving aids, NBC protection, improved communications suite and other minor changes.
The M577 has been adopted by various police forces and law enforcement agencies (mostly in the U.S.) as a tactical response or hostage rescue vehicle. Agencies that use the vehicle in this role include:
Between 1994 and 1997, NASA (who operated four M113A2 Armored Rescue Vehicles up to the end of the Space Shuttle program) trialled the eXperimental HAZMAT Response Vehicle (XHRV-1), a modified M577A3 specifically designed for dealing with HAZMAT incidents i.e. emergency incidents involving hazardous materials. The vehicle, on loan from FMC, was a collaboration between NASA and the Ames Research Center, and featured an extended 6-axle chassis similar to that of the M577A2E2, as well as external fuel tanks similar to those fitted to the M113A3.
At the front was a manipulator arm for use with the hazardous materials. The driver's hatch was replaced with a transparent polycarbonate dome, and the vehicle was hermetically sealed and fitted with an overpressure air conditioning system. The APU, normally attached to the front of the upper hull to the right of the driver, was removed. At the rear the cargo ramp was replaced with two sealed "suit ports", attached to each was a HAZMAT suit so that personnel could enter and exit the vehicle without being exposed to the hazardous materials. In addition to the vehicle's driver and commander, the rear cargo/personnel area was fitted with seating and workstations for four operators. On the roof of the upper hull was a "robotic miniature helicopter" (i.e. a drone) fitted with stereoscopic cameras and environmental sensors, which was remotely controlled from inside the vehicle. In conceptual artwork the roof featured another transparent polycarbonate dome to provide external visual access to the operators, but this was not implemented on the actual vehicle.
Only one prototype vehicle was built and is now on public display (repainted as a military ambulance) at Eagle Field in California.