NTSB CAROL · Event
Event MIA94LA003
Aircraft involved
Probable cause & findings
PARTIAL FAILURE OF A WING RIB DUE TO EXFOLIATION CORROSION AND INADEQUATE INSPECTION OF THE AIRCRAFT BY COMPANY MAINTENANCE PERSONNEL.
Factual narrative
On October 7, 1993, about 1940, Atlantic standard time, a Douglas DC-3C, N781T, registered to and operated by Tol Air Services, Inc., under 14 CFR Part 135, flight No. 522, as a nonscheduled, international, cargo flight, was substantially damaged on landing at the Luis Munoz Marin International Airport, San Juan, Puerto Rico. Visual meteorological conditions prevailed at the time and an IFR flight plan was filed for the flight from Santiago, Dominican Republic. The airline transport-rated captain and commercial-rated copilot were not injured. The flight originated about 2 hours 2 minutes earlier. The pilot-in-command stated that the second pilot had landed the airplane and while taxiing, he observed that an outer section of the left wing was bent up. Examination of the airplane revealed that Rib No. 19 of the left wing failed. The failed rib was removed and sent to Douglas Aircraft Company for analysis. Analysis of the rib revealed that it failed chordwise due to exfoliation corrosion midpoint between the rivet line and the nutplate line on the lower horizontal section. According to McDonnell Douglas personnel, the location of the corrosion could not be observed by a flightcrew when performing a walk around inspection but can be observed during the FAA approved 50-hour inspection. Review of the FAA approved 50-hour inspection checklist used for the inspection specifically states to inspect all interior structures for corrosion, damage condition and security. Additionally, the outer wing attach angles and bolts are required to be inspected. AFTER AN UNEVENTFUL LANDING WHILE TAXIING, THE CAPTAIN NOTICED THAT A SECTION OF THE LEFT WING WAS BENT UP. EXAMINATION OF THE AIRPLANE REVEALED THAT RIB NO. 19 IN THE LEFT WING FAILED CHORDWISE MIDPOINT BETWEEN A ROW OF RIVETS AND NUTPLATES ON THE LOWER ATTACH ANGLE DUE TO EXFOLIATION CORROSION. THE FAA APPROVED 50-HOUR INSPECTION REQUIRES VISUAL INSPECTION OF THE ATTACH ANGLE AND BOLTS BUT DOES NOT REQUIRE REMOVAL OF THE WING TIP. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1993_MIA94LA003.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2026 · Journal article (IJAAA)
From Reactive to Predictive: A hybrid Trust-Mediated Adoption Framework for Data-Driven Maintenance in Distributed-Authority Aviation Environments
Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains incon…
- Semantic Scholar 2025 · Article (Applied Sciences)
Decision-Making Framework for Aviation Safety in Predictive Maintenance Strategies
The implementation of predictive maintenance (PM) in aviation presents unique challenges due to strict safety requirements, complex operational environments, and regulatory constraints.
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
Low-Resource Automatic Speech Recognition Domain Adaptation – A Case-Study in Aviation Maintenance
With timeliness and efficiency being critical in the aviation maintenance industry, the need has been growing for smart technological solutions that optimize and streamline the different underlying ta…
- Embry-Riddle Scholarly Commons 2024 · Journal article (JAAER)
A New Trajectory in UAV Safety: Leveraging Reinforcement Learning for Distance Maintenance Under Wind Variations
In the field of aviation, safety is a critical cornerstone, and the operation of Unmanned Aerial Vehicle (UAV) systems is deeply connected with this principle.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Just Culture in Aviation: A Metaphorical Study on Aircraft Maintenance Students
Just Culture, a sub-dimension of safety culture, has been a prominent and debated topic in aviation safety in recent years.
- Embry-Riddle Scholarly Commons 2024 · Journal article (IJAAA)
Performance PRISM: A Comprehensive Framework For Performance Measurement In Aircraft Maintenance
Aircraft maintenance is governed by rigorous safety requirements and high operational complexity, demanding robust performance measurement frameworks to ensure optimal maintenance practices.
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