Iberia Flight 933

Iberia Airlines

Industry	Airline
Founded	1927 (1927)
Headquarters	Madrid , Spain
Products	Air transport services

Iberia Flight 933 was an international service flying from Madrid Barajas International Airport to Boston's Logan International Airport that experienced a crash landing on December 17, 1973. During its final approach, the McDonnell Douglas DC-10 struck the approach lighting system (ALS) approximately 100 feet short of the runway threshold, resulting in the detachment of the right main landing gear. The plane briefly lifted off again for about 300 feet before touching down on runway 33 Left, after which it veered right and came to a stop. Although all 168 passengers and crew survived, the aircraft was declared a total loss, representing the first hull loss involving a DC-10.

Aircraft

The aircraft involved was a McDonnell Douglas DC-10-30 built in early 1973 at Long Beach Airport, California. At the time of the incident, it had accumulated 2,016 flight hours over nine months of service. Originally registered as N54627 during its certification phase, it was re-registered as EC-CBN upon delivery to Iberia Airlines in August 1973. This particular aircraft had also been prominently featured in Iberia’s marketing campaigns.

Crew

The flight deck team consisted of Captain Jesus Calderón Gaztelu (53), First Officer Alfredo Perez Vega (54), Flight Engineer Celedonio Martin Santos (42), and Radio Operator/Navigator Candido Garcia Bueno (51). Captain Calderón joined Iberia in 1953 and had amassed 21,705 flight hours, including 426 on the DC-10. First Officer Perez, with a hiring date of 1946, logged 34,189 hours overall and 403 in the DC-10. Flight Engineer Martin entered service in 1952 and held 15,317 hours with 263 on this model. Radio Operator/Navigator Garcia, employed since 1941, had completed 14,562 flight hours including 384 on the DC-10.

Investigation

The National Transportation Safety Board (NTSB) concluded that the accident was caused by an unrecognized rapid descent triggered by wind shear during the approach phase. Both captain and first officer failed to notice the accelerating descent rate until the aircraft impacted the approach light system supports. Shifts in weather conditions distracted their attention from descent monitoring. The NTSB highlighted that the critical switch from automatic to manual control under limited visual cues and minimal clearance between DC-10 wheels and approach lights significantly reduced pilots’ reaction time and compromised landing safety.

Examination after the accident showed that only half of the eight emergency exits were functional; specifically, the number 1 right exit was jammed due to a mechanical failure. Structural deformation of the cabin floor near the rear damaged seat rails, restraint systems, and two emergency exits, forcing passengers seated at the back to evacuate through a broken roof section—this increased injury risk. The floor collapse occurred between fuselage stations 1530 and 1850—the same vulnerable area that failed in American Airlines Flight 96—revealing a repeated structural weakness in DC-10 design.

Aftermath

On September 6, 1974, the NTSB issued seven safety recommendations directed at the Federal Aviation Administration (FAA), all of which received satisfactory responses.

• A-74-77: Reposition ILS glide slope transmitter sites according to FAA Order 8260.24 to improve safety margins for wide-body aircraft executing Category I approaches.

• A-74-78: Temporarily raise decision height (DH) and visibility minimums for approaches where glide slope antenna placement results in less than 20 feet wheel clearance over the runway threshold.

• A-74-79: Accelerate updates to U.S. instrument approach procedures to display glide slope runway threshold crossing heights when TCH is below 47 feet until transmitter relocation is completed.

• A-74-80: Publish an advisory circular focusing on wind shear phenomena with emphasis on pilot awareness, recognition techniques, and monitoring descent rate, attitude, and thrust during autopilot/autothrottle approaches.

• A-74-81: Revise pilot training curricula to incorporate education on wind shear effects and appropriate countermeasures.

• A-74-82: Expedite research and implementation of Acoustic Doppler Wind Measuring Systems.

• A-74-83: Develop an interim mechanism to communicate wind shear information derived from meteorological data or pilot reports to inbound and outbound flights.

The aircraft EC-CBN sustained damage beyond repair and was officially written off two months following the accident; it was dismantled in 1974.

See also

• Pan Am Flight 845 and Emirates Flight 407, comparable cases involving collisions with ALS equipment during the takeoff phase

External links

• NTSB accident investigation report (Alternative source)
• ASN detailed accident report