Investigation Summary
The accident aircraft, a CASA C-212 Aviocar, had a documented history of engine torque and thrust issues. Just one day prior to the crash, maintenance personnel at Executive Air Charter had attempted to address problems with the propeller blade angle. On the morning of the accident, the flight was operating five minutes behind schedule. During the final approach to Mayagüez, the captain conducted a non-standard, tight turn onto the final approach path, overshooting the extended centerline. As the aircraft descended, witnesses and surviving passengers noted irregular engine sounds, described by one witness as similar to a turboprop entering reverse pitch. The NTSB determined that the improperly set flight idle blade angle caused the right engine to produce insufficient thrust, creating a severe yaw to the right. The aircraft then rolled to the left, as if the pilot had attempted to counteract the yaw, before rolling back to the right and striking the ground right-wing-first. The investigation was complicated by the absence of a Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR), which were not required for commuter aircraft at the time, and the lack of radar data because the local control tower was closed due to FAA budget cuts.
Final Conclusions
The National Transportation Safety Board (NTSB) determined the probable cause was improper maintenance in setting the propeller flight idle blade angle and engine fuel flow, which resulted in a loss of control from an asymmetric power condition. A contributing factor was the pilot's unstabilized visual approach. The NTSB also found that Executive Air Charter's maintenance program did not conform to approved standards, specifically regarding the recording of required inspections and the approval of aircraft for return to service.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Franklin Rivera Velez, age 44. Held ATP certificate.
First Officer
Reynold Santiago Cordero, age 32. Held ATP certificate; not type rated in the CASA C-212.
Systems & Failure Modes
Propeller Flight Idle Blade Angle
A mechanical setting that determines the minimum pitch of the propeller blades during flight; improper adjustment led to asymmetric thrust when the power was reduced.
Garrett TPE331-10R-511C Engines
The turboprop engines powering the CASA C-212; maintenance issues with fuel flow and torque settings contributed to the power loss.
Interesting Facts
- 01The aircraft had 6,264 total airframe hours and 11,774 cycles at the time of the accident.
- 02The Mayagüez control tower was closed at the time of the accident due to FAA budgetary constraints.
- 03The aircraft was not equipped with a CVR or FDR, as they were not legally required for this class of commuter aircraft in 1987.
- 04All four passengers survived the impact and subsequent fire with only minor injuries.
- 05The flaps were found in the 'up' position after the crash, which was contrary to standard landing procedures.
Safety Actions & Advisories
Maintenance Oversight
The NTSB recommended stricter adherence to approved maintenance programs and more rigorous recording of required inspections for commuter airlines.
Flight Recorder Requirements
Following this and other similar accidents, the NTSB reiterated the need for Cockpit Voice Recorders (CVR) and Flight Data Recorders (FDR) to be required on smaller commuter aircraft to aid in accident investigation.