Iberia Flight 933
Douglas DC-10 · Pilot error leading to spatial disorientation
From Adolfo Suárez Madrid–Barajas Airport (MAD) to Boston Logan International Airport (BOS)
Event
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Unknown
- Event fatalities
- 0 · all aircraft and ground
- Ground fatalities
- 0
- Occupants
- 168
- Survivors
- 168
- InjuriesFatal: death within 30 days. Serious: over 48 hours in hospital within a week, most broken bones, severe bleeding, nerve or organ damage, or serious burns. Minor: anything less. Glossary
- 13
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
Douglas DC-10
- Flight
- IB933
- Aircraft type
- Douglas DC-10
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- EC-CBN
- Operator
- Iberia
- Onboard fatalities
- Unknown
- Route
- From Adolfo Suárez Madrid–Barajas Airport (MAD)To Boston Logan International Airport (BOS)
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air carrier (scheduled international passenger service)
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Approach
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Undershoot
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Miscellaneous › Written cause
Approximate · Coordinates from the Wikipedia article; not checked against an investigation report.
From the Wikipedia article
Iberia Flight 933 was a flight from Madrid Barajas International Airport to Boston Logan International Airport in Boston that crash landed on December 17, 1973. As the McDonnell Douglas DC-10 operating the flight was approaching the airport, it collided with the approach lighting system (ALS) 500 feet short of the runway threshold. The impact broke off the right main landing gear. The aircraft became airborne for about 1,200 feet, then landed on runway 33 Left, veered to the right off the runway and came to rest. All 168 on board survived, but the plane was written off. This accident was the first hull loss of the DC-10.
Investigation and cause
Investigation
The National Transportation Safety Board (NTSB) investigated the accident. According to the aircraft's flight data recorder, the descent rate was increasing too rapidly during the approach, the result of a wind shear encounter. The investigation found that the captain and the first officer failed to recognize the rate change until the aircraft collided with the ALS piers. It was also discovered that the changes in weather had directed their attention away from monitoring the descent rate. Eleven months after the accident, the NTSB issued its conclusion on the probable cause of the crash. In its accident report the NTSB stated: "The captain did not recognize and may have been unable to recognize, an increased rate of descent in time to arrest it before the aircraft struck the approach light piers. The increased rate of descent was induced by an encounter with low-level wind shear at a critical point in the landing approach where he was transitioning from automatic flight control under instrument flight conditions to manual flight control with visual references. The captain's ability to detect and arrest the increased rate of descent was adversely affected by a lack of information as to the existence of the wind shear and the marginal visual cues available. The minimal DC-10 wheel clearance above the approach lights and the runway threshold afforded by the ILS glide slope made the response time critical and, under the circumstances, produced a situation wherein a pilot's ability to make a safe landing was greatly diminished."
The DC-10 had eight emergency exits, but after the crash, only four could be operated. The number 1 right exit had a fault in the mechanism and could not be opened. Due to the weak floor at the end of the aircraft, the floor had become deformed, causing failures in multiple-seat tracks and restraints, and also destroyed the two emergency exits at the back of the aircraft. This meant that the passengers in the back had to climb out of the section through the roof that had broken and jump off onto the ground, causing even more injuries. Due to the floor disintegrating, rock and mud were thrown into the rear compartment of the aircraft.
The parts of the floor that had broken apart were between fuselage stations (sections in the aircraft fuselage) 1530 to 1850. Compared to American Airlines Flight 96, stations 1801 to 1921 had failed. The same floor section had collapsed in both accidents.
Text from the Wikipedia article “Iberia Flight 933” (revision 1346104334, retrieved 2026-09-18) by its authors, under CC BY-SA 4.0. Extracted as plain text: references, tables, images and some sections are left out. Read the article
NTSB remarks
LOW ALT WND SHEAR.MIN WHL CLNC.APCH LITE PIERS. PLT-DIDNT RECOG INCR DSCNT RATE,MAY HV BEEN UN TO
NTSB's remark from its 1962–1981 archive, as recorded (abbreviated, at most 98 characters): the archive has no narrative
Sources
Wikipedia article: Iberia Flight 933
- Article
- Iberia Flight 933
- Revision
- 1346104334 · 2026-03-29 · retrieved 2026-09-18
- Wikidata
- Q48817584
- Licence
- Text CC BY-SA 4.0, by the article's authors; Wikidata CC0; town positions GeoNames (CC BY 4.0)
NTSB record
- Event ID
- 19731217P052342
- Case number
- Unknown
- Dataset
- historical-pre1982
- Source SHA-256
- abe1a933b4b73583d61684309f7f0610c281e3c1de3537c6471bf2a98ba6481d
Where each value comes from
- Record
- Wikipedia article "Iberia Flight 933" (page 56543906, revision 1346104334); merged with NTSB case NTSB19731217P052342 (PRE1982 tblFirstHalf (one row per aircraft, grouped by date, place and time))
- Date
- NTSB record NTSB19731217P052342: PRE1982 DATE_OCCURRENCE
- Place and country
- Wikipedia infobox: site; country from NTSB record NTSB19731217P052342
- Map position
- Wikipedia: Wikipedia article coordinates
- Aircraft, operator and route
- NTSB record NTSB19731217P052342: PRE1982 REGIST_NO, ACFT_MAKE, ACFT_MODEL; gaps from Wikipedia infobox: aircraft type, registration, operator, origin and destination; route airports from the linked airport articles' Wikidata codes (OurAirports)
- Operation
- NTSB record NTSB19731217P052342: operated under Part 121: Air carrier (scheduled intl passg service)
- Fatalities
- NTSB record NTSB19731217P052342: PRE1982 TOTAL_ABRD_FATAL of each aircraft, plus people on the ground and others outside the aircraft
- Ground fatalities
- NTSB record NTSB19731217P052342: events.inj_f_grnd
- Summary
- Wikipedia infobox: summary
Source notes (4)
- One occurrence in two sources, merged: the Wikipedia article "Iberia Flight 933" and NTSB case NTSB19731217P052342, matched by the same aircraft registration and date. For this US event the NTSB's values are used where the two differ; each value names its source.
- From NTSB's 1962-1981 archive (PRE1982), which holds at most a short remark (98 characters, abbreviated) instead of a narrative; the accident type, phase of flight, causes and conditions are NTSB's codes, decoded as the archive defines them.
- Reviewed means this record passed the site's consistency check, not that it was checked against a narrative or report - there is none to check against.
- The operation category is mapped from the archive's operator and operation codes and has not been reviewed.