Prior to the jets entering service, the Mexican Air Force, an integrated unit of the Mexican Army, had relied on a mixture of World War II aircraft for aerial operations, including the Republic P-47D Thunderbolt fighters, that were the same as the ones deployed by México during World War II in the Philippines. Because of the decades of fighting due to the Mexican Revolution and wars with the United States and other nations, México embraced a pacifist attitude towards foreign affairs. México has traditionally looked inward for its military and security needs.
World War II forced México to consider foreign affairs as a necessary evil regardless of México’s stated foreign policy of non-intervention. Internal political necessities also kept the Mexican military lacking in combat capabilities due to the government’s policy of keeping the military subservient to the civil authority.
However, the United States feared a Nazi foothold on its southern border. The U.S. also needed access to México’s natural resources as well as oil to start its combat readiness programs. The United States started a program of collaboration with México. México responded by keeping its neutrality for as long as possible while at the same time ramping up its defense capabilities. However, the Mexican government saw the U.S. need as an opportunity to bolster its defensive capabilities. The World War II México-U.S. collaboration resulted in México’s first and only foreign military deployment, the Mexican Army air wing, Squadron 201. After the war, México ended up with a large number of different types of World War II combat aircraft. These were the backbone of México’s Air Force through the late 50’s.
Exclusive Economic Zones
México is bordered by three countries, the United States in the north, and Belize and Guatemala on south. The Atlantic and the Pacific oceans border it on the west and east. México saw its greatest security concern as internal. War with the United States was lopsided at best, and Belize and Guatemala did not pose a military threat of invasion.
By the late 1950’s littoral waters and natural resources off the coasts of countries was becoming an international issue. Specifically, offshore fishing was lucrative for many countries. Oil soon followed. Countries started to respond to littoral resources by expanding its economic littoral zones from three miles to twelve miles from the country’s shores. Fishing and other economic activities are controlled by the country which controls the littoral zone.
By 1983, under the United Nations Convention on the Law of the Sea, countries had increased their Exclusive Economic Zones (EEZ) from 12 nautical miles to 24 and then to 200 nautical miles from their shores.
México and Guatemala were feuding over fishing resources in the 50’s. On December 31, 1958, two Guatemalan Air Force P-51D Mustangs attacked Mexican fisherman twelve miles off México’s waters.  México had recently extended its EEZ from three nautical miles to twelve. Three Mexicans were killed by the Guatemalan aircraft and fourteen Mexican fishermen were captured by Guatemalan authorities. The Guatemalan military named the strafing operation Operación Drake.
The Guatemalan Affair
Mexican president Adolfo López Mateos responded to the Guatemalan attack by ordering the military to immediately prepare a retaliatory strike. López Mateos also demanded the return of the captured fishermen and an apology from the Guatemalan government. Meanwhile, while the international incident was played out in public, the Mexican Army activated Operación Gaviota (Operation Seagull) to attack the Guatemalan air base where the P-51’s were based.
As tensions rose in México and in Guatemala, both governments were concerned that the other would mount a military invasion. The Mexican military realized that Guatemala’s P-51 Mustangs were a serious threat for air superiority over México. The Mexican air superiority P-47D Thunderbolts had been retired. Three P-47D Thunderbolts were immediately refurbished and put back into service.
A mixed fleet of prop-driven Mexican aircraft were assembled at a base in México’s southern border at Tuxtla Gutiérrez in the state of Chiapas. The attack squadron consisted of three P-47s for air superiority, T-28s and AT-6s for the bombing mission. The Mexican squadron’s target was the La Aurora airbase in Guatemala City. A Douglass C-47 was tasked to act as the command center for the attack.
The plan called for three flights. The T-28s were loaded with NAPALM bombs for bombardment. They were designated as bravo flight whose mission was to bomb the Guatemalan airbase housing the P-51s. If the Guatemalan P-51s could get airborne, the AT-6s, the alfa flight, armed with .50 caliber machine guns and rockets would defend the bombers. Mexican intelligence thought that the Guatemalan air defense consisted of two alert fighters and 20mm anti-aerial batteries. The three P-47D Thunderbolts would provide air superiority for the attack. The AT-6s, armed with 100lb fragmentation bombs would also bomb the airfield to deprive the Guatemalan P-51s their base.
This much is known. However, two versions have evolved overtime as to what happened next. The official version is that Operación Gaviota never launched. Then Mexican president Adolfo López Mateos had been in office for less than a month when the Guatemalans strafed the Mexican fishermen. López Mateos wanted to be recognized as ushering in a new era in Latin American diplomacy with México leading it. He also wanted to be elected as the next Organization of American States (Organización de Los Estados Americanos) leader. Ordering an attack against Guatemala would destroy that ambition.
The other version is a frequent topic among students at the Escuela Militar de Aviación in Guadalajara.
After crossing the Guatemalan border, the strike package dropped to 80 feet above the ground and commenced their attack run. Suddenly, only minutes from reaching their objective, the C-47 combat center aircraft issued the order to abort the attack. The Mexican attack flight returned to México.
Operation Seagull had ended without attacking its objective.
The reason for aborting the attack is unknown. However, the United States had been rumored to have notified the government of Adolfo López Mateos that the U.S. was aware of the attack on Guatemala and that it was in the United States’ interest that the attack be aborted to end the controversy peacefully. [see author’s note below for more information about the attack plan]
On September 15, 1959, the Mexican and Guatemalan government finally ended the controversy by resuming diplomatic relations. Both countries officially apologized for their part in the controversy while Guatemala paid reparations to the injured fishermen and to the families of the families of those killed.
For the Mexican military, the outcome was clear, México needed the ability to better respond to foreign aggression to its southern border under the framework imposed on it by the government’s demand that the military remain subservient to civil authority while at the same time embracing the doctrine that offensive weapon systems were for sovereignty defense only.
From that moment on, a future expeditionary force for México was off the table and the limited capability to defend against aggression from the southern border took second seat to maintaining internal security.
The Mexican military operates under a three-prong doctrine known as national defense plans. They are Defensa Nacional I, II and III, or DN-I, DN-II and DN-III. DN-I is national sovereignty defense. DN-II is counterinsurgency (COIN) operations, or internal security. Drug trafficking was added under the De La Madrid administration to DN-II. DN-III is disaster recovery. National defense under DN-I comes in last in budgetary planning decisions.
The Jets Arrive in México
In response to the Guatemala incident, the Mexican military embarked on a modernization program for its air force. In 1960, México deployed fifteen ex-Canadian de Havilland Vampires. Those were followed by fifteen Lockheed AT-33A Shooting Stars it purchased from the United States.
On August 10, 1982, two Northrup F5e Tiger II’s arrived in México City. Aircraft 4501, an F5f and aircraft 4001, an F5e were the first to arrive. Aircraft 4002 and 4003, both F5e’s arrived four days later. On August 20, 1982, an F5e, 4004 and an F5f, 4502 landed in Mexico City. On August 28, F5e, 4005 arrived to complete the initial seven aircraft for the new squadron. 
On September 16, 1982, seven F5’s flew over Mexico City during the Independence Day parades. Shortly after, the squadron was completed. It consisted of ten F5e and two F5f trainers. The era of supersonic interceptors had begun in México. On November 1, 1982, Escuadrón Aéreo de Defensa 401 was fully deployed with twelve fighters, ten F5e and two F5f Tiger IIs. 
Northrop Grumman flew the first F5 on July 31, 1963 at Edwards Air Force Base in California. Between 1964 and 1989, 2,600 variants of the F5 were built in the United States and under license in Canada, China, Korea and Switzerland.  In February of 1965, Northrop Grumman started offering the F5 as an export combat aircraft under the United States Military Assistance Program (MAP). MAP was consolidated under the Foreign Military Financing Program in 1990. Foreign Military Sales (FMS) is the program whereby the United States sells weapons systems to other countries. To entice the purchase of U.S weapons over competitors, the United States government offers financing packages to countries purchasing U.S. weapons systems. The market was worth $40 billion to U.S. manufacturers in the early 1990’s.  Almost all of that, about $30 billion, was directly related to aerial assets.
By 1993, about 2,250 McDonnell Douglas and General Dynamics aircraft had been sold to other countries. Foreign military sales had peaked in 1987, weapons systems sales had been declining steadily since. Although it remained a significant market for U.S. manufactures. Between 1966 and 1975, 74 nations purchased weapons systems from the United States. 
In 1974, México announced a significant increase in its oil reserves. It started to look to exploit the larger resource. It also needed to protect the oil fields from foreign aggression. The Mexican Army started to look for air superiority assets that could respond quickly. The T-33 fleet was limited in its ability to run interception missions, as its primary role had focused on ground operations.
The Mexican military has traditionally tried to keep its dependence on U.S. weapons systems as low as possible. The air force began to look for aircraft for air superiority functions while the army looked for funding from the government. The Mexican military entertained offers from Brazil, Britain, France, Germany, Israel and the United States.
On April of 1978, the Mexican government dropped its request to purchase 26 Northrop F5 combat aircraft.  In 1977, Jimmy Carter issued Presidential Directive No 13. The directive changed the direction of the United States foreign policy away from arming friendly nations to one of weapons sales to other countries was now an exception to U.S. foreign policy. The United States restricted the sales of weapons systems to other countries. 
In 1977, the Mexican government officially requested the purchase of 26 Northrop F5 for $150 million to augment it air defense capabilities.  The initial price for the F5 was $750,000 each. But it was agile and a simple supersonic aircraft that could outperform the MIG-17. 
Stymied by Carter’s noncommitment to allow the purchase of the Northrop F5s, the Mexican government looked to Israel’s Kfir fighter planes. Although there was much speculation that the Kfir’s would be México’s next fighter plane, by 1981, the much-anticipated sale had been cancelled by the Mexican government. Officially, the sale was ended by México because the aircraft was deemed too expensive.  México had been in the market for 24 fighters. It had budgeted $300 million for the purchase from Israel.  Because the Kfir uses General Electric J79 engines, the United States maintains veto power over the sale of any of those aircraft to other nations. Although the Mexican government argued that the Kfir order was cancelled due to budget concerns, unofficially, Jimmy Carter’s reluctance to allow arms proliferation played part in the cancellation of the sale. Carter had refused to allow the sale of the aircraft 30 times over his presidency. Carter had only authorized a sale to Taiwan.
By 1981, the F5 was back on the table for México. The Mexican government had made a secret request in November of 1980 to the United States government directly to the incoming president. On January 20, 1981, Ronald Reagan assumed the presidency. Ronald Reagan had launcheded his presidential quest by announcing the development of the North American Common market. With Reagan’s rapprochement towards México and Carter’s exit, it gave México the opportunity to modernize its air force. 
México paid $106 million for the package of a dozen Northrop F5 Tiger II’s.  The purchase was conducted under the Foreign Military Sales program. It was coded FMS IF-70 by the U.S. government. The purchased was known as the Peace Aztec program, officially.
Mexican Northrop F5 Tiger II Inventory (source: Northrup Grumman)
1. Contract No: 1271 Serial no: 81-0632 Type: F5E No: MX1001 Aircraft No: 4001
2. Contract No: 1272 Serial no: 81-0633 Type: F5E No: MX1002 Aircraft No: 4002
3. Contract No: 1273 Serial no: 81-0634 Type: F5E No: MX1003 Aircraft No: 4003
4. Contract No: 1274 Serial no: 81-0635 Type: F5E No: MX1004 Aircraft No: 4004
5. Contract No: 1275 Serial no: 81-0636 Type: F5E No: MX1005 Aircraft No: 4005
6. Contract No: 1276 Serial no: 81-0637 Type: F5E No: MX1006 Aircraft No: 4006
7. Contract No: 1277 Serial no: 81-0638 Type: F5E No: MX1007 Aircraft No: 4007
8. Contract No: 1278 Serial no: 81-0639 Type: F5F No: MY1001 Aircraft No: 4501
9. Contract No: 1279 Serial no: 81-0640 Type: F5F No: MY1002 Aircraft No: 4502
10. Contract No: 1282 Serial no: 81-0823 Type: F5E No: MX1008 Aircraft No: 4008
11. Contract No: 1283 Serial no: 81-0624 Type: F5E No: MX1009 Aircraft No: 4009
12. Contract No: 1284 Serial no: 81-0625 Type: F5E No: MX1010 Aircraft No: 4010
Except for Cuba, which had Soviet Migs, the F5’s were the first supersonic combat aircraft in Latin America. 
The Mexican F5 fleet was deployed to safeguard Mexican airspace. They were based at the Santa Lucia airbase in Mexico City.
The Mexican Tigers were capable of air-to-air supersonic combat as well as ground attack roles. They were armed with AIM-9P Sidewinder missiles, two on each wingtip as well as two 20mm cannons for the F5e and one cannon for the F5f. The fighters could also be armed with Mk82 and Mk83 bombs and rocket launchers for COIN operations.
The squadron’s official designation was changed from Escuadrón Aéreo de Defensa to Escuadrón Aéreo 401 in 1997. Pilots aspiring to fly the fighters were required to build 250 flight hours over two years at the school of aviation. From there, they transferred to an active squadron consisting of PC-7s for another two years. The national command then selected pilots to transition on to the T-33 jets. From there, a select few pilots were selected to qualify for the F5 Tiger II’s. Those selected had to pass a qualification course of 14 dual flights before being selected to command one of the F5e’s.
The aircraft typically operated in flights of three to four aircraft at a time, depending on the mission. After 9/11, when México started to deploy alert status aircraft, it kept two interceptors on a ready status to respond to air incursions.
In 1983, one of the aircraft, 4002, was lost in a training accident.
In 1995, another F5e was lost during the September 16 parade when an F5e (4003) collided with a T-33 which then collided with two other T-33s.
In 2000, the remaining ten aircraft were overhauled in early 2000. GPS was added and the radar systems were upgraded to the AN/APQ-159 systems.
After the 9/11 terrorists’ attacks, México again reevaluated its air defense capabilities. The military determined that other than increasing training air defense interception missions, the Tiger fleet would continue to provide drug trafficking interdiction support services. However, Squadron 401 started providing alert standbys for possible incursions. Prior to 9/11 training on fast-reaction interception missions took back seat to drug interdiction operations.
Although not seen frequently in public, the 401-squadron continued to fly missions, although the costs for fuel and maintenance forced the F5 into near retirement. This resulted in the loss of qualified pilots and the reallocation of resources towards aircraft more capable of COIN operations.
In 2012, then-President Felipe Calderón Hinojosa, tweeted pictures F5 Tigers (4507) escorting the Mexican Presidential plane on its way to Washington DC.
As the decades went by, the ten fighters saw their maintenance costs increase dramatically. During Felipe Calderón’s War on Drugs, the operational flight times for the F5 increased from 332 flight hours in 2000 to almost 1,000 flight hours in 2010.
As the Mexican Tigers were nearing 35 years of operation service, the Mexican government started looking for replacements. Very little information was officially released publicly, but what is known is that the Mexican Army wanted to purchase 12 F16 Block 30 fighters. Competition among the military branches is common place in many countries. México is not an exception.
During the drug operations under the administration of Calderón, the Mexican Navy gained the reputation as the most effective military unit in México. It started an attempt to bolster its air units. Rumors started to surface that the Mexican Navy was in the market for Russian SU-27 fighters.
The Mexican Army, who keeps the Mexican Air Force under its domain, reacted angrily by arguing that the job of safeguarding the Mexican airspace rested on it, and not on the navy. The Mexican Army wanted to keep fighters under its domain.
The last of the Mexican F5 Tigers were retired in September 2016.
1. Gillespie, Harvey; Canada Aviation and Space Museum Aircraft pamphlet, unknown date.
2. New York Times, January 1, 1959
3. Cámara de Diputados LXII Legislatura; Fuerza Aérea Mexicana, La Aviación Militar, Un Siglo de Historia (1915-2015), 2014
4. Northrop Grumman
5. Peterman, Robert N.; Fighter Aircraft Foreign Military Sales: Industry Survival and National Power; The Industrial College of the Armed Forces, National Defense University, 1993
6. Goshko, John M.; Mexico Drops Request to Buy F5 Jets, Eases Diplomatic Dilemma for Carter; The Washington Post, April 20, 1978
7. Vartabedian, Ralph; Era of the F-5 Ends After Three Decades; Los Angeles Times, January 16, 1987
8. Simons, Marlise; U.S. Said to Approve Jet Sale for Mexico’s Military Buildup Plan; The Washington Post, February 24, 1981
9. Siempre No; Processo, January 31, 1981
10. Robles, Manuel; Incierta, aún, la compra de aviones israelís; Processo, January 17, 1981
11. Riding, Alan; Regional Power Seems Aim in Mexico’s U.S. Jet Deal; New York Times, May 10, 1981
12. Mexican government response to open records request
Author’s note: The Operación Gaviota details are derived from the author’s notes taken in 1986 from a conversation held with an individual, who said he had first-hand knowledge of the operation. The individual demanded anonymity to discuss the plan openly. Additionally, the story is repeated regularly as fact at the school of aviation in Guadalajara among the student body.
Visit the F5e.org webpage for more information about the Northrop F5 Tiger II’s.