IATA Aircraft Lease Guidance

Background
determined period. As a result, perceptions and interpretations of specific requirements differ quite often.
Figure 3 illustrates how the interests of Lessor and Lessee may vary.
Figure 3.
Interest of Different Stakeholders
1.2.1 Back-to-Birth Traceability
One of the items most commonly misunderstood in a lease agreement is how to prove ‘Back-to-Birth
Traceability’ (BtB) for ‘Life Limited Parts’ 1 (LLP).
LLPs exist in a number of aircraft components, such as engines, APUs, landing gears and airframe parts.
Failure of an LLP may result in unsafe conditions or safety hazards and therefore a life limit has been
imposed. Major regulatory agencies, such as the Federal Aviation Administration (FAA) and the European
Aviation Safety Agency (EASA), simply state that an operator must have an approved system in place that
1
“Life Limited Part is any part for which a mandatory replacement limit (in hours, cycles or calendar time) is specified in the type design, the
mandatory continuing airworthiness information or instructions for continuing airworthiness. These parts must be permanently removed
from service on or before this limit is reached.” ICAO Airworthiness Manual Doc 9760
4 th Edition 2017 3