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

Special Conditions: Boeing Model 727-200 and 727-200F Series Airplanes; as Modified by Rockwell Collins; High-Intensity Radiated Fields (HIRF)

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 March 13, 2000 for Rockwell Collins. System: other and general.

What it applies to

Applicant
Rockwell Collins
Makes
Boeing
Models
—
Published
March 13, 2000
Effective
March 5, 2000
The FAA's document
On the FAA's site

The FAA's summary their words, unchanged

These special conditions are issued for Boeing Model 727-200 and 727-200F series airplanes modified by Rockwell Collins. These modified airplanes will have a novel or unusual design feature associated with the Rockwell Collins Multi-Mode Receiver (MMR) System. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These 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.