October Thirteen, Nineteen Seventy-Two, the Fairchild Over the Cordillera, and the Controlled Flight Into Terrain That Became One of Aviation History's Most Haunting Stories

On October 13, 1972, Uruguayan Air Force Flight 571 - a Fairchild FH-227D carrying 45 people - flew into the Andes because its crew believed they had already cleared them. The aircraft was functional, the crew was competent, and the weather was not the direct cause. The cause was a navigation calculation that was off by a few minutes and a few miles, in terrain that offered no margin for error. Sixteen people made it home.

What Kind of Aircraft Was Flight 571?

The Fairchild FH-227D was a stretched, Americanized variant of the Fokker F27 Friendship, built by Fairchild-Hiller under license from Fokker. It was powered by two Rolls-Royce Dart turboprops and capable of approximately 250 knots in cruise. Several South American air forces operated these aircraft as passenger transports by 1972. The Uruguayan Air Force had acquired theirs a few years before the accident.

The aircraft was mechanically sound. The crew was trained and experienced. There was no equipment failure before departure.

The Route and Why It Was Dangerous

The standard route from Montevideo to Santiago crosses the southern Andes. The Cordillera in that region rises from roughly 12,000 feet to nearly 23,000 feet at Aconcagua - the highest point in the Western Hemisphere. The Fairchild FH-227D cruised at approximately 18,000 feet, threading between peaks with minimal vertical margin.

The standard procedure required the crew to climb to altitude over the flat Argentine pampas, confirm their position over a navigational fix at Curicó on the Chilean side, then begin descent into the Santiago valley. The key word was confirm.

What Went Wrong: Dead Reckoning in the Cordillera

The flight actually began on October 12, 1972. The crew departed Carrasco International Airport in Montevideo but stopped in Mendoza, Argentina - on the eastern slope of the Andes - when weather over the mountains deteriorated. They spent the night.

On October 13, conditions appeared better. Captain Julio César Ferradas occupied the left seat with co-pilot Dante Héctor Lagurara. They departed Mendoza heading west, into the mountains.

In 1972, there was no satellite navigation, no moving map, and no terrain avoidance system. Navigation across the Andes relied on dead reckoning: flying a heading, tracking elapsed time, estimating groundspeed, and calculating when checkpoints should be reached. The crew had filed a leg time of approximately 22 minutes from Mendoza to the Curicó beacon.

What they did not fully account for was a significant headwind along the route. Upper-level winds over the southern Andes are notoriously variable and often poorly reported. A headwind reducing groundspeed by even 20 to 30 knots over a 22-minute leg shifts actual position back several miles. In that part of the Andes, several miles is the difference between being past the mountains and still being inside them.

When elapsed time reached 22 minutes, the crew’s calculation indicated they had passed Curicó. Captain Ferradas radioed Santiago Approach: “We are past Curicó. Beginning descent.” Santiago approved.

They were not past Curicó. They were still above the mountains - over an unnamed glacier at approximately 14,000 feet, surrounded by peaks that rose considerably higher.

The Impact

The Fairchild FH-227D began its descent. The right wing struck a lower ridge and sheared away. The tail section separated. The cockpit and forward fuselage continued down the slope, the cabin acting as a toboggan on the glacier until it came to rest at approximately 11,800 feet elevation.

Of the 45 people aboard, 12 died at impact or within hours. Thirty-three survived the initial crash. The wreckage sat deep in the Cordillera in October - the southern hemisphere winter - with temperatures dropping to minus 40 degrees Fahrenheit at night. No shelter except the broken fuselage. No food after the first week. No way to communicate.

The Search That Found Nothing

The Uruguayan Air Force launched a search immediately, joined by Chilean and Argentine air forces. Fixed-wing aircraft and helicopters crisscrossed the search area for eight days.

They could not find the wreck.

The Fairchild FH-227D’s fuselage was painted white. The glacier was white. The snow-covered peaks offered no visual contrast. From altitude, the wreckage was effectively invisible. The search was suspended on October 22, 1972.

On October 23, some survivors recovered a small transistor radio from the tail section debris, roughly a mile and a half from the main fuselage, and got it running. They heard a broadcast from Montevideo confirming that the search had been abandoned. No survivors were expected.

The Avalanche

On October 29, 1972, an avalanche came down during the night and buried the fuselage while most of the survivors slept inside. Eight more died. The remaining sixteen were injured, malnourished, altitude-sick, and committed to a southern hemisphere winter with no prospect of external rescue.

In the weeks that followed, survivors stripped the aircraft for insulation, fashioned eyewear from wreckage components to prevent snow blindness, and captured snowmelt for water. They improvised a sleeping bag from seat foam and fuselage wall material.

The Walk Out

Nando Parrado and Roberto Canessa concluded the only viable exit was to hike west - over the remaining mountains into Chile. Having studied the charts recovered from the cockpit, they estimated the Pacific coast was no more than 50 to 60 miles in a straight line. They had no climbing gear, no rope, and no ice axes.

On December 12, 1972, Parrado and Canessa left the fuselage carrying food rationed for ten days.

On December 21, after crossing glaciers, snow bridges, and a roughly 4,000-foot descent into the Chilean foothills, Parrado found a trail. The following day he located a Chilean cattle rancher named Sergio Catalán working on the far side of a mountain river. Unable to cross, Catalán threw paper and a pencil across the water. Parrado wrote a note describing what had happened and where the fuselage was located.

Catalán rode three hours on horseback to reach the nearest telephone.

On December 22, 1972, the first helicopters reached the fuselage. On December 23, the last survivors were evacuated. All sixteen were alive.

What This Accident Taught Aviation

Flight 571 became foundational to the understanding of controlled flight into terrain (CFIT) - the scenario in which a fully functional aircraft is flown into terrain by a crew who may not recognize their actual position until it is too late. CFIT remains one of the leading causes of fatal aviation accidents worldwide, and accidents like Flight 571 directly influenced the development of ground proximity warning systems (GPWS) in the years that followed.

The specific failure here - a crew committed to a dead reckoning position that was meaningfully wrong - is not unique to 1972 or to the Andes. It occurs whenever a pilot substitutes a calculated estimate for a confirmed fix and acts on that estimate with confidence. It occurs in flat terrain. It occurs in instrument conditions. It happens any time the calculation is trusted more than the available evidence warrants.

The crew was not reckless. They were flying a difficult route with the best tools available to them. But those tools produced a wrong answer, and the mountains had already decided the outcome.

What Remains

The tail section and portions of the Fairchild FH-227D are still on that glacier. The fuselage was never recovered. Aerial photographs taken in recent decades show sections of the aircraft re-emerging from the retreating ice - slowly surfacing after more than five decades.

Nando Parrado returned to the site by helicopter in 1993. He has said the aircraft still looks as though it could be on a ramp - if you did not know the story.

The sixteen survivors lived full lives. Parrado became a motorsport enthusiast and television personality. Roberto Canessa became a cardiologist. Both have spoken publicly about the accident for decades, insisting it be told accurately and without sensationalism. Their account is documented in Piers Paul Read’s 1974 book Alive, based on extensive firsthand interviews.

Why This Matters for Mountain Pilots

Every mountain crossing that relies on dead reckoning carries the same fundamental risk: the actual position and the calculated position are not the same thing. Upper-level winds shift groundspeed. Timing errors compound. The confidence a crew feels in their calculation does not change where the aircraft actually is.

The Curicó beacon was there. The crew never received it because they were never in range of it. They descended based on time elapsed, not position confirmed.

Before any mountain crossing, check actual winds against filed winds and track groundspeed continuously. Do not declare a fix passed until it is confirmed - by a beacon, a visual fix, or GPS. In high terrain, acting on an incorrect position estimate can be immediate and unrecoverable.

The Andes that day offered no negotiation with an estimate.

Key Takeaways

• Uruguayan Air Force Flight 571 crashed in the Andes on October 13, 1972 due to a dead reckoning navigation error; the aircraft was airworthy and the crew was competent
• An unreported headwind reduced groundspeed enough to place the aircraft miles inside the mountains when the crew believed they had cleared them - they began descent over an unnamed glacier at 14,800 feet rather than over the Chilean foothills
• A white fuselage on a snow-covered glacier made aerial search nearly impossible; the official search was suspended after eight days
• The accident contributed directly to the development of ground proximity warning systems (GPWS) and remains a textbook case for CFIT training worldwide
• The core lesson holds for any mountain pilot today: a calculated fix and a confirmed fix are not the same thing - never commit to terrain-critical maneuvering on an estimate alone