ACP/WG-M/9 WP-3

AMCP

Working Group B/M Meeting

Montreal, Ca

October 27-November 3, 2004

Certification of VDL Mode 3 on an Airlines Aircraft


Summary

Presented by

The US Member

Prepared by

Peter Muraca

Bruce Eckstein

1.0 Introduction

The FAA established a program known as the Next Generation Air/Ground Communications (NEXCOM) Program to establish the future communication system for the NAS. The technology being implemented by that program was the VHF Digital Link Mode 3. As part of the efforts to implement the system, FAA understood a task to insure that the certification of the VDL Mode 3 technology could be achieved in users aircraft. This task was implemented by contracting with 3 avionics developers, Rockwell Collins, Honeywell and Avidyne to develop avionics radios. These radios were to achieve Certification approvals through a Technical Standard Order (TSO)process and then proceed to obtain a Special Type Certificate (STC) on user aircraft with the VDL Mode 3 multimode radios installed for operational use. This paper describes the final stages of the certification.

2.0 Testing

Rockwell Collins, who has a partnership agreement with Delta Airlines, conducted an STC over-flight test at the WJTHC on October 16th, 2004. Individuals representing engineering and management from Delta Airlines, Rockwell Collins, FAA Air/Ground Communications, the WJHTC, the FAA Certification organizations of FAA AIR-130 and the FAA ACO were on hand to witness and assist in the conduct of the day’s events. The STC flight validated the functionality of Very High Frequency (VHF) Digital Link Mode 3 (VDL Mode 3) communications equipment, approved for and installed in the Delta Boeing 737-800 (Flight ID 9997).

STC testing took place over Atlantic City airspace, radiating in the VHF bandusing pre-approved test frequencies. Pretest preparation, company ground testing and a lighting evaluation was conducted in Atlanta, Georgia, prior to arrival in Atlantic City. Three Rockwell Collins VHF Digital Radios (VDR) and three Radio Tuning Panels (RTP), manufactured by Gables Engineering, were installed on the Delta aircraft. The minimum performance standards, for the VDRs (VHF-2100) operating in the 117.975-137.000 frequency range, was verified and approved for a Technical Standard Order (TSO) prior to the STC over flight at the WJHTC. The below description is a synopsis of STC activities;

An analog radio was utilized so as to maintain a backup form of communications in case an anomaly occurred that inhibited communications. The majority of testing was conducted at a flight altitude of 35,000 feet, unless otherwise specified or dictated by the condition, with each procedure utilizing one of the three installed VDR’s. Testing accomplishments include the full validation of the STC Flight Plan, the procedures of which verified requirements necessary for an STC for the VHF-2100 with installation in a Boeing 737-600-700-800 type aircraft. Verified were the following;

  • Intelligible transmission and reception of digital voice communications during long-range operations (greater than 160nm), including both right and left 360 degree maneuvering. Communications was monitored and exchanged every 10 degrees of the turn. Procedure 2.1.1
  • Intelligible transmission and reception of analog voice communications during long-range operations (160nm), including both right and/or left 90-180 degree maneuvering. Communications was monitored and exchanged every 20-30 degrees of the turn. Procedure 2.1.6
  • Intelligible transmission and reception of digital voice communications during high angle operations, including both right and left 360 degree maneuvering. Test conducted between 50-70 nm range. Communications was monitored and exchanged every 10 degrees of the turn. Procedure 2.2.1
  • Intelligible transmission and reception of analog voice communications during high angle operations, including both right and left 360 degree maneuvering. Test conducted between 50-70 nm range. Communications was monitored and exchanged every 20-30 degrees of the turn. Procedure 2.2.6
  • Intelligible transmission and reception of digital voice communications during approach operations. (Aircraft modified flight level from 35,000 to 15-20,000 feet). Test conducted at 20 nm range while also performing left and right arc maneuvers. Communications was monitored and exchanged during the complete turn. Procedure 2.3.1
  • Intelligible transmission and reception of analog voice communications during approach operations. (Aircraft modified flight level from 35,000 to 15-20,000 feet). Test conducted at 20 nm range while also performing left and right arc maneuvers. Communications was monitored and exchanged during the complete turn. Procedure 2.3.6
  • Controller Override operation. Pilot transmits phonetic alphabet, controller interrupted pilot’s transmission, communications exchanged to validate normal transmission and reception after the override function. Procedure 2.4.1
  • Urgent Downlink Request operation. Controller transmits phonetic alphabet while holding PTT, pilot initiates urgent downlink request, communications exchanged to validate normal transmission and reception after the downlink request function. Procedure 2.5.1
  • Next Channel Uplink operation. Controller uplinks next channel, the uplinked channel is displayed in the standby window on radio tuning panel, new channel is transferred to the active window, communications exchanged to validate normal transmission & reception after the next channel uplink function. Procedure 2.6.1
  • Analog data-ACARS operation (Aircraft Communications Addressing And Reporting System [ACARS]). Atlanta and Atlantic City weather data displayed on the Control Display Unit (CDU). Procedure 2.7.1
  • Transmitter Timeout (35 second timer) operation. Pilot transmits phonetic alphabet. Controller monitors time, side tone initiates, and transmission is inhibited. Communications exchanged to validate normal transmission and reception after a 35 second timer condition. Procedure 2.8.1
  • Polling function analysis during co-site analog reception. This test performed using multiple VDRs. A VDR was logged onto the ground station to a digital frequency (119.221), a second VDR was tuned to a second analog frequency (136.300), the second analog frequency was monitored for VDL Mode 3 polling bursts. Polling bursts were not heard and did not affect voice quality of communications. Procedure 2.9.1
  • Mutual interference evaluation of VHF-2100 operations and other aircraft systems. Multiple systems operated and no unacceptable mutual interference between the VHF-2100’s and the systems observed. Procedure 2.10.1
  • Radio to radio interference of the VHF-2100s. Multiple radio to radio combinations tested, using all three VDRs, and no unacceptable mutual interference between the VHF-2100s observed. Procedure 2.10.6
  • Mutual interference of the VHF-2100s during Instrument Landing System (ILS) Category IIIB (Cat IIIB) approach. Two Autopilot/Flight Director (AP/FD) ILS approaches to CAT IIIB minimums to 50 feet Above Ground Level (AGL) performed, while monitoring for lateral/vertical deviations. No unacceptable mutual interference on ILS approach performance detected from the VHF-2100s. Procedure 2.11.1
  • Accessibility, readability and usability of the VHF comm radio controls and displays and VHF Comm1, VHF Comm2 and VHF Comm3 circuit breakers. Light conditions were evaluated per both the night and day perspectives (night time conditions were induced using covers for the windshield). All three comm radios controls and displays were accessible by each pilot from their normal crew positions, were legible and visible in all lighting conditions, and were convenient to use (preventing any confusion and/or inadvertent operation). Procedure 2.12.1
  • Transmission and reception of VHF-2100s with various microphones and speakers/headsets. Transmission on all microphones is intelligible by ground station and reception on all listening devices is intelligible by flight crew. Procedure 2.12.6
  • VHF radio failure Test. Once the circuit breaker is pulled, the radio tuning panel is blank and the radio does not transmit/receive. After resetting the circuit breaker the tuning panel is illuminated and the radio transmits and receives.

3.0 Conclusion

VDL Mode 3 operational avionics system has been developed, installed and certified on a users’ operational aircraft. This validation was completed to the satisfaction of the certification services of the FAA. The Delta Aircraft has since been returned to operational service by Delta Airlines.