The U.S. aircraft register, updated daily
Special conditions · aircraft

Special Conditions: Airbus, A350-900 Series Airplane; Interaction of Systems and Structures

Special conditions are rules the FAA writes for one design when the standard certification rules do not cover something new about it. These were published December 19, 2013 for Airbus. System: airframe structure.

What it applies to

Applicant
Airbus
Makes
Airbus
Models
—
Published
December 19, 2013
Effective
February 2, 2014
The FAA's document
On the FAA's site

The FAA's summary their words, unchanged

These special conditions are issued for Airbus Model A350-900 series airplanes. These airplanes will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. These designs features include systems that, directly or as a result of failure or malfunction, affect structural performance. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

Source: FAA special conditions (final) from the Dynamic Regulatory System; the Federal Register carries the same notices.