FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-03/13

Title and Subtitle: Automatic Dependent Surveillance - Broadcast/Cockpit Display of Traffic Information: Pilot Use of the Approach Spacing Application

Report Date: October 2003

Authors: Prinzo OV, Hendrix AM

Abstract: Pilots may benefit from surveillance technology that enhances their ability to maintain pre-determined distances from other aircraft during initial and final approach. Avionics that provide a cockpit display of traffic information (CDTI) enable pilots to acquire, verify, establish, and maintain pre-defined spacing intervals from other aircraft. It is of interest to the Federal Aviation Administration to determine how the use of these displays influences safety, capacity, and efficiency. The second operational evaluation of ADS-B/CDTI provided an opportunity to evaluate procedural modifications needed to support operational approval for Approach Spacing and Visual Acquisition/Traffic Awareness applications.

Ten flight crews flew 86 approaches during 3 day and 2 night operations. Subject-matter experts read transcripts and listened to 9 hrs of audiotapes for the presence of problems and operational concerns stemming from pilot use of the CDTI. Controllers issued 169 traffic calls that resulted in 70% positive visual acquisitions (83% displayed on CDTI, 17% not displayed), which resulted in a 48% increase in visual approach clearances (up from 23 to 34).

Eighty-three percent of the approach clearances that included an instruction for the pilot to "follow that traffic" were transmitted 2 s or less after the pilot reported that the traffic was visually acquired. Approximately 55% of these visual approaches involved one or more problems. Problems included uncertainty (33%), speed overtakes (28%), lost visual contact (11%), confusion (8%), clearance copied by "traffic" (8%), follow traffic not sighted (6%), and aircraft call sign (6%). The use of a CDTI created some problems for the participants, including several from the call sign procedure that distinguished between the aircraft being talked to versus talked about. In light of the findings and the participants' comments, changes to proposed procedures and supporting phraseology will be constructed and evaluated for the approach spacing application.

Key Words: Pilot Communication, CDTI, ATC Communication, Air Traffic Control

No. of Pages: 20