Modern Transport Engine Experience With Environmental Ingestion Effects

Modern propulsion engines have achieved a high level of reliability while manufacturers and users are always striving to further improve the safety record. The drive for safety in single-engine aircraft has resulted in safer multiple-engine applications. In modern turbofan-powered transports it is extremely unlikely that a failure intrinsic to an engine would initiate a sequence of events which could result in loss of capability for continued safe flight and landing. These rare events are limited to uncontained rotor disk fracture or uncontrolled fire.

Of greater concern today are the non-intrinsic, common-cause events which involve power loss of more than one engine. These are externally-inflicted occurrences such as ingestion events or common-cause maintenance events resulting in simultaneous loss of power on more than one engine. The most frequent are those ingestion events involving products of the flying environment - flocking birds, ice, volcanic ash and extreme inclement weather.

This environmental ingestion hazard viewed in overview is the primary subject of this paper. There is a body of knowledge on each of these subjects. Data from field operations and engine experience have provided guidelines for recognition of an occurrence and the proper action response. The primary precaution however remains - be aware, prevent, communicate and avoid.