AIRPORT--Without speculating about todayโs event, the following mechanisms are recognized by the U.S. National Transportation Safety Board (NTSB) and by the Transportation Safety Board of Canada (TSB), as well as in aviation safety literature and investigations as potential contributors to landing gear collapse on landing in 737 series aircraft. Only the operator, manufacturer, and accredited investigators can determine the cause in any specific case.
๐๐ฏ๐๐ซ๐ฅ๐จ๐๐ ๐๐ซ๐จ๐ฆ ๐ฅ๐๐ง๐๐ข๐ง๐ ๐๐ฒ๐ง๐๐ฆ๐ข๐๐ฌ: An unstabilized approach or a hard, nose-first touchdown can exceed structural limits at the nose gear, leading to failure during or after touchdown. Excessive sink rate or improper pitch attitude can concentrate loads beyond design margins.
๐ ๐๐ญ๐ข๐ ๐ฎ๐ ๐๐ซ๐๐๐ค๐ข๐ง๐ ๐ข๐ง ๐ญ๐ซ๐ฎ๐ง๐ง๐ข๐จ๐ง ๐ฉ๐ข๐ง๐ฌ ๐จ๐ซ ๐ซ๐๐ฅ๐๐ญ๐๐ ๐ก๐๐ซ๐๐ฐ๐๐ซ๐: Main landing gear trunnion pins and attachment fittings can develop fatigue cracks over time, especially if prior maintenance introduced finish damage, corrosion, or grinding beyond limits. Progressive cracking can culminate in fracture under landing loads.
๐๐๐๐ซ ๐ฌ๐ก๐ข๐ฆ๐ฆ๐ฒ ๐๐ง๐ ๐ญ๐จ๐ซ๐ฌ๐ข๐จ๐ง ๐ฅ๐ข๐ง๐ค ๐๐๐ฆ๐๐ ๐: Excessive wheel or gear shimmy can overstress torsion links, bushings, and fasteners. Fracture or loss of torsion link integrity can allow destructive oscillations that contribute to collapse or severe gear damage during rollout.
๐๐จ๐๐ค๐ข๐ง๐ ๐๐ง๐ ๐๐ซ๐๐๐ข๐ง๐ ๐ข๐ฌ๐ฌ๐ฎ๐๐ฌ ๐จ๐ซ ๐ฆ๐ข๐ฌ-๐ซ๐ข๐ ๐ ๐ข๐ง๐ : Side braces, drag braces, and down-lock mechanisms must engage and be correctly rigged. If weakened by wear, damage, or mis-rigging, or if subjected to abnormal side loads, the gear can unlock or move out of its intended geometry under load.
๐๐จ๐ฆ๐ฉ๐จ๐ง๐๐ง๐ญ ๐จ๐ซ ๐๐ฑ๐ฅ๐ ๐๐๐ข๐ฅ๐ฎ๐ซ๐๐ฌ ๐๐ญ ๐ญ๐ก๐ ๐ง๐จ๐ฌ๐ ๐ ๐๐๐ซ: Structural failures of inner cylinders, axles, or associated components can occur due to hidden defects, corrosion, or prior overloads, leading to loss of support during taxi, touchdown, or rollout.
Actual determinations rely on a structured process, which includes aircraft inspection, teardown of damaged components, review of maintenance and overhaul records, analysis of flight data and cockpit voice recorders where applicable, and coordination with the aircraft manufacturer and the relevant civil aviation authorities.
๐๐จ๐จ ๐๐๐ซ๐
A pilot can land an aircraft โtoo hardโ and trigger a landing gear collapse. A โhard landingโ occurs when the vertical speed at touchdown exceeds the aircraftโs design limits, sending forces through the landing gear and fuselage that can cause structural failure. While gear is designed with safety margins, an excessively hard touchdown can overwhelm those margins, especially if combined with poor pitch angle or crosswind.
So, while rare, a landing that is too hard has directly caused a 737โs landing gear to collapse. This is why airlines track hard-landing data from the flight data recorder, and maintenance crews must perform structural checks if a hard-landing threshold is exceeded.
๐๐ข๐ฅ๐จ๐ญ ๐๐๐๐จ๐ซ๐ญ
When an aircraftโs landing gear collapses, the pilot is immediately faced with one of the most demanding scenarios in aviation. The landing gear is not only the structural support for the aircraft on the ground, it also stabilizes the aircraftโs balance during rollout. Once that support is compromised, the aircraft can yaw violently to one side, drag a wingtip, or scrape the engine nacelles and fuselage against the runway surface.
For the pilots, this means they must apply maximum control inputsโusing rudder, ailerons, and sometimes asymmetric thrustโto keep the aircraft tracking straight on the runway and prevent a total loss of directional control. They must also coordinate with braking systems that may now be compromised, since part of the landing gear is not functioning.
Communication and split-second decision-making become critical: one pilot focuses on controlling the aircraft while the other manages checklists, communicates with the tower, and prepares for an evacuation if needed.
The challenge is heightened because everything happens in seconds, at relatively high speeds (often 120โ150 knots on touchdown). It requires intense training, coordination, and composure under pressure. The fact that in many such incidents passengers walk away unharmed speaks volumes about both pilot training and the design redundancies of modern aircraft.
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https://tribune-site.webflow.io//articles/how-and-why-landing-gear-could-collapse-on-landing-a-boeing-737
