What happened
Upon completing the landing phase at José Tadeo Monagas International Airport in Maturín, the crew of an Estelar Latinoamerica C.A. Boeing 737-2B7, registration YV2792, attempted to perform a 180-degree turn on runway 06-24. During this maneuver, the crew noticed that the nose wheel steering was unresponsive. Upon inspecting the hydraulic system, the flight crew found that the indicator for hydraulic system "A" was reading zero.
The pilot notified the control tower to coordinate the disembarkation of the 58 occupants (seven crew members and 51 passengers) and the movement of the aircraft to the apron. There were no injuries reported during the event.
The investigation
The investigation involved interviews with the captain and first officer, a review of crew licenses and medical certificates, and an examination of maintenance records. Investigators also performed a photographic survey of the area where hydraulic fluid (Skydrol) leakage was evident.
A troubleshooting procedure was conducted in accordance with the Aircraft Maintenance Manual (AMM). This inspection revealed damage to one side of a flexible hydraulic line. The damaged component was subsequently replaced, and the system was tested to ensure satisfactory operation.
Findings
The investigation established that the failure was caused by the rupture of the wire braid (protective mesh) on a flexible hydraulic line. This degradation was attributed to constant vibrations experienced during landings, which caused the mesh to lose elasticity and eventually crack. This cracking led to a perforation in the hydraulic line, resulting in the leakage of Skydrol fluid.
Safety action
The JIAAC issued a preventive recommendation to the maintenance management to implement periodic cleaning of these lines using a Boeing-recommended solution, along with applying a protective anti-corrosion compound or equivalent.