Overview
An incident occurred when the #1 engine of an aircraft experienced a flameout as a result of water ingestion. The event took place after the aircraft penetrated a VIP level 5 thunderstorm and encountered heavy rain while descending with throttles set to flight idle. The engine sustained overtemperature damage to its turbine section during the subsequent windmilling start.
Event Details
The captain chose to descend through precipitation with the engines at idle, despite a warning from the copilot that this procedure contradicted recently published guidelines. Those guidelines required maintaining a minimum of 45% N1 RPM during such conditions. The descent with throttles at flight idle in heavy rain led to the ingestion of water, causing the flameout.
Background
Precipitation-induced flameout phenomena had been previously identified in other incidents. Corrective procedures had been issued by the Federal Aviation Administration (FAA), the aircraft and engine manufacturers, and the carrier prior to this occurrence. The published procedures explicitly called for maintaining engine power above a specific threshold to prevent flameouts in heavy rain.
Aftermath
After the flameout, a windmilling start was attempted, which resulted in overtemperature conditions that damaged the turbine section. The extent of the damage necessitated further investigation and potential engine replacement. The incident highlighted the importance of adhering to established procedures for operating in adverse weather conditions.