What happened
On January 5, 2008, an EMB 202 Ipanema, registration PT-UPZ, was performing agricultural positioning maneuvers near Alto Taquari, Mato Grosso, when the engine lost power. The aircraft was at approximately 100 feet of altitude when the failure occurred.
In response to the power loss, the pilot jettisoned the agricultural spray load from the hopper and executed a forced landing in a cerrado area. During the descent, the aircraft collided with trees, causing extensive damage to the landing gear, fuselage, and propeller. The pilot sustained minor injuries, and the aircraft sustained severe damage.
The investigation
The CENIPA investigation focused on the mechanical failure of the engine and the operational procedures followed by the crew. Laboratory tests conducted on the mechanical fuel pump revealed that it was failing to produce sufficient pressure. Upon disassembly, investigators found that the central stem of the pump had detached from the drive lever. This failure was attributed to fatigue, as multiple cracks were identified in the stem region.
Investigators also examined the operational status of the auxiliary electric fuel pump. While the aircraft's operating manual mandates that the electric pump remain active during takeoffs, agricultural operations, and landings, the investigation established that the pilot had deactivated the pump shortly after takeoff. Furthermore, the investigation noted that the mechanical pump was an "on-condition" component, meaning it was not subject to scheduled maintenance intervals, which contributed to the undetected fatigue of the part.
Findings
- The primary cause of the engine failure was the fatigue-induced rupture of the mechanical fuel pump's central stem.
- The pilot's decision to deactivate the auxiliary electric fuel pump, contrary to the manufacturer's operating manual, prevented the engine from receiving a secondary fuel supply after the mechanical pump failed.
- A professional culture among agricultural pilots, where the electric pump is often turned off to prevent perceived wear, contributed to the operational error.
- The design and maintenance classification of the mechanical fuel pump were contributing factors, as the initial lack of scheduled maintenance intervals allowed the fatigue crack to progress undetected.
Safety action
Following the investigation, several safety actions were implemented:
- The manufacturer, Indústria Aeronáuma Neiva Ltda., issued Service Bulletins to reinforce the use of the auxiliary electric pump via new technical markings on the instrument panel and provided procedures for the timely replacement of mechanical fuel pumps.
- ANAC (National Civil Aviation Agency) was tasked with alerting EMB 202 Ipanema operators regarding the mandatory use of the electric pump as specified in the operating manual.
- Airworthiness Directive (DA) No. 2008-04-01 was implemented to regulate the maintenance and replacement intervals of the mechanical fuel pump.