Equivalent Level of Safety
ELOSSection 04: Certification Process Mechanics
Definition
A formal determination by the certifying authority that an alternative means of compliance, while not literally meeting the text of a specific airworthiness requirement, provides a level of safety equivalent to that intended by the requirement. An ELOS finding allows the applicant to use compensating factors, design features, or operational limitations that achieve the same safety objective through different means. ELOS findings become part of the certification basis for the specific project.
Where This Shows Up
ELOS findings are distinct from exemptions: an ELOS maintains the same level of safety through alternative means, while an exemption provides relief from a requirement entirely. ELOS findings are common when new technologies or design approaches do not fit the literal text of older regulations but achieve the underlying safety objective.
Primary Sources
FAA provision for equivalent safety findings in type certification.
Across Jurisdictions
14 CFR § 21.21(b)(1)
The FAA documents ELOS findings through Issue Papers and includes them in the certification basis summary.
Part 21, 21.A.21(c)
EASA processes equivalent safety findings through the CRI mechanism and publishes them in the certification programme.
Related Terms
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