The International and State Defense Police (PIDE) – predecessor of the General Directorate of Security (DGS) – only discovered that the ARA was an organization linked to the PCP in the sabotage of the Tancos air base, with the code name, Operation "Águia Real" (Royal Eagle), due to the complexity involved and the size of the feat, which destroyed 28 aircraft, 13 of them irrecoverably.
In the meeting of the Central Committee of the Portuguese Communist Party held in December 1962, the question of using violence as a means of self-defense and its relation to mass actions was discussed for the first time.
The April 1964 report Towards Victory endorsed the use of armed struggle but stressed that the main objective of the "Democratic and National Revolution" was to mobilize the masses to overthrow the regime and its repressive apparatus.
It causes enormous harm in that it influences the democratic forces away from their essential, instantaneous, immediate tasks, without which they can never launch a victorious insurrection: the mass struggle and organization.The most radical sectors included students and workers from the South Bank of the Tagus River.
[5] The PCP faced a complex situation, balancing Cunhal's criticisms, the Soviet Union's policy of peaceful coexistence, the most radical sectors of the workers' and students' movements, and attempts to reach agreements with other opposition groups.
[17] After five months of recruitment involving Rogério de Carvalho, Raimundo Narciso, and the Portuguese Communist Party, the "special actions" group had assembled a team ready to commence operations.
According to Raimundo Narciso, attempts to contact the PCP in Lisbon were conducted "with the utmost care to avoid approaching anyone being monitored by the PIDE and to ensure that our cautiousness was not mistaken for a trap by the political police".
[30] According to Ana Ferreira in her PhD thesis on Contemporary History, "the ARA was a highly disciplined organization, and its members were fully aware of the risks associated with their involvement and participation in armed actions".
[32] The planning involved detailed reconnaissance of the Algés dock and its surroundings, including the routes and timings of meetings, with strict adherence to compartmentalization and non-overlapping interactions among team members.
[34] The operation team included Raimundo Narciso, Francisco Miguel, Carlos Coutinho, Gabriel Pedro, António João Eusébio, Manuel Policarpo Guerreiro, and Victor d'Almeida d'Eça.
[36] As a result of this action the ship CUNENE [capital letters in the original], of 16,000 tons used to feed the colonial war, was flooded and immobilized in the Alcântara dock, in Lisbon, with a big hole.
[44] In the early morning of March 8, 1971, one of the ARA's most significant actions occurred: the sabotage of the Tancos air base, which led to the destruction of numerous military airplanes and helicopters.
[46] The operatives responsible for executing the action included Ângelo de Sousa, Carlos Coutinho, and António João Eusébio, who would be transported to the base by a hired car.
[46] In the early morning hours of March 7, 1971, the commandos involved in the action convened at a clandestine ARA apartment on Estados Unidos da América Avenue to verify the electrical systems and ensure all preparations were in order.
It also noted that "the increasingly predominant anti-colonialist sentiment among Portuguese soldiers, sons of the people in uniform, contributed decisively to its success", concluding with the rallying cry: "Down with the colonial war!
[50] The defense of your organization; the just evaluation of the political conjuncture and of the effect of each action to be undertaken; the effort to be efficient, always taking into account the actual strength at one's disposal and the enemy's strength and devices; initiative and audacity, not to be confused in any way with impatience and rashness; the effort to make the most of surprise and to best pick off the enemy where he may be unprepared; careful work to achieve the objectives without leaving a trace, nor a clue – such seem to us to be some of the essential norms for the continuity and progress of your action.Álvaro Cunhal also emphasized that the revolutionary movement in Portugal had limited experience with this type of struggle.
[52] On June 3, 1971, several ministers from NATO member countries gathered in Lisbon, accompanied by hundreds of international journalists covering the high-profile meeting, which was enthusiastically promoted by Marcello Caetano.
[53][52] This act of sabotage against the national and international telecommunications center during the NATO ministerial conference created significant embarrassment for the regime and was widely reported globally, including by French newspaper Le Figaro, the English The Guardian, and on BBC and West German radio.
Despite this, the operation succeeded in damaging several poles, leading to power outages in certain areas of Lisbon, including the Palace of Ajuda, where the NATO meeting was taking place.
They condemned the meeting for providing "moral and political support to the fascist and colonialist government" of Portugal, viewing it as a provocation against the Portuguese people, who had long been deprived of basic democratic freedoms supposedly championed by NATO.
This was the only action of its kind undertaken by the ARA, driven by the limited stock of explosives they had and heightened security at military barracks due to the increased frequency of attacks against the regime that year.
[56] One of the ARA commanders, who lived near the target and was familiar with several of its employees, provided crucial inside information about the building, contributing to the operation's success, according to Jaime Serra.
The selection of operatives was a matter of intense debate between Raimundo Narciso and Francisco Miguel, as Carlos Coutinho, Ângelo de Sousa, Eusébio, and Jaime Serra—some of the ARA’s most experienced members—were in Moscow undergoing technical-military training.
The government had planned a grand public event with NATO’s top generals, Secretary-General Josef Luns, and Supreme Allied Commander of the Atlantic, Admiral Charles Duncan, to showcase Portugal's support from the international community and counteract perceptions of isolation.
[...] Sheet-iron gates and metal doors from that sector of the warehouse were hurled and twisted down the wharf, while the stairway leading to the top-floor office was completely blocked by debris from collapsed brick and reinforced concrete walls.
[...] But it was actually in the warehouse that the damage was felt the most, since its reinforced concrete structure was able to resist, to some extent, the violence of the plastic loads placed there, it is not clear where or how.The ARA acquired information about the construction of patrol vessels in Figueira da Foz, designated for the Guinea war, including details on their operation, logistics, and other relevant aspects, from a member of the local PCP organization.
The ARA's plan for this event involved coordinated sabotage actions aimed at disrupting power across the country, targeting Belas and Vialonga in Lisbon, Ermesinde in Oporto, and Coimbra.
With the assistance of the Portuguese Communist Party, which provided support in terms of transportation and accommodation—operatives were lodged in the homes of PCP members for several days—two houses were secured: one for assembling the explosives and another to serve as a clandestine laboratory, storage facility, and sleeping quarters.
[67] The ARA's statement explained that the suspension of certain actions was a strategic decision in light of the emerging broad political movement in the country, which was seen as crucial for weakening the fascist and colonialist dictatorship.
That man was a scoundrel, who deserved to die five hundred times, but that operation should never have happened because it challenged [...] the collective conscience, questioning the nature of a left that wanted to be necessary, just, and ethical."