Correspondence

Additional Evidence from Jan’s Research

Flying Magazine, November 1962 (Source Now Attributed)

Jan identifies the pre-announcement quoted in the earlier edition of this note as appearing in the November 1962 issue of Flying magazine, page 120, accessible at books.google.com (ID: S-45uoS-v04C, p. 120).¹ This confirms and strengthens the provenance of the January 1963 date: Flying was the pre-eminent US general aviation magazine of the era, and its annual equipment survey was based on manufacturer briefings and factory visits. The article is now the definitively attributed primary source for the 618M-1 introduction date and the late-1963 860E DME forecast.

1963 Collins Advertisement in British Aviation Press

Jan has identified a 1963 Collins advertisement in the British Aviation Ancestry advertisement database (query: Collins, 1960–1964).² The direct image link is Avionics-Collins-1963-52126.jpg. A Collins advertisement in the British aviation trade press in 1963 carries significant weight: UK Civil Aviation Authority approved equipment was required to hold type approvals before advertising for installation in British-registered aircraft, meaning any unit advertised in 1963 was available for commercial installation in that year, not merely announced.

Collins Jet Commander Avionics Catalogue, 1964

The Collins Jet Commander avionics brochure (1964), preserved at the Collins Aerospace Museum,³ documents the standard Collins SSS avionics fit for the Aero Commander Jet Commander turbofan business jet. Factory fit brochures are significant because they show which units were not only available but approved and routinely installed. The 1964 date places this document one year after the SSS launch, confirming the system was in full production. Jan correctly observes this is “generally on-line with” the 1963 advertisement evidence.

The Collins 50th Anniversary Book — A Caveat

Jan raises an important methodological point about the Collins 50th anniversary book: dates in that publication may represent the start of development rather than first customer delivery. He cites the AN/ARC-51 as a specific example where the anniversary book date appears inconsistent with independent evidence. This is a recognised problem with corporate anniversary publications generally. Collins Radio was, by the 1960s, a company with significant government and military contracts; many programmes had classified development phases that preceded the public product introduction by several years. For establishing when a particular avionics unit could have been factory-installed in a 1960s aircraft, Jan’s hierarchy of sources is correct:

1. Contemporary advertisements in aviation trade press (UK or US) — strongest evidence of market availability
2. Factory-fit brochures (e.g. the Jet Commander 1964 catalogue)
3. Contemporary equipment survey articles in aviation magazines (Flying, Aviation Week)
4. FAA/CAA type approval dates
5. Service manual first-edition dates
6. Anniversary book dates — use with caution; may reflect development start

Collins Radio Company — Avionics Context

Collins Radio Company, founded by Arthur A. Collins in 1933 in Cedar Rapids, Iowa, became a world leader in avionics during the 1950s and 1960s. Two product generations frame Jan’s enquiry: the 1963 Solid State System and the c. 1970 Pro Line I. The merger with North American Rockwell was completed on 2 November 1973.⁴

  COLLINS RADIO AVIONICS — PRODUCT GENERATION TIMELINE
  ──────────────────────────────────────────────────────────────────────
  1933   Collins Radio Company founded, Cedar Rapids IA
  1950s  Collins 618T HF transceiver — airline standard
  ──────────────────────────────────────── SSS ERA ─────────────────────
  Nov 1962  Flying magazine p.120: SSS announced; 618M-1 Jan 1963 ★
  Jan 1963  618M-1 VHF COM — HIGH CONFIDENCE ★★★
  1963      UK Collins ad (Aviation Ancestry) confirms SSS units ★
  Late 1963 860E DME — forecast in Nov 1962 Flying ★★
  1964      Collins Jet Commander catalogue: SSS avionics confirmed ★
  1963-65   860E in production — ESTIMATED
  1966-70   618M-2/2B/2D variants — ESTIMATED
  ──────────────────────────────────── ROCKWELL TRANSITION ─────────────
  2 Nov 1973  Collins Radio → Rockwell International
  ────────────────────────────────────── PRO LINE I ERA ────────────────
  c. 1970-72  51R-7A • VIR-30/30A • DME-40 ★★
  c. 1972-75  51R-8A ★ (relative to 51R-7A)
              51RV-1/-2/-4 ★ (Pro Line I era estimated)
  c. 1970-80s 618M-3 through 618M-5A
  Late 1970s  ARINC 429/CSDB digital control replaces ARINC 410 wire
  ──────────────────────────────────────────────────────────────────────
  ★★★  Multiple independent primary sources (highest confidence)
  ★★   Single primary source or strong corroborating evidence
  ★    Estimated from generation-era confirmation or indirect evidence

Figure 1. Collins Radio avionics product generation timeline with revised source confidence coding.

1. 618M — VHF COM Transceiver Series

Introduction Date: January 1963

The 618M-1 was certified to TSO-C37b / TSO-C38b. It covered 118.000–135.975 MHz in 50 kHz steps (20 channels), with later variants extending to 151.975 MHz. Primary installations: Boeing 707, 727, early 737, Douglas DC-8, DC-9, and business jets including the Learjet, Cessna Citation, and Aero Commander Jet Commander (the last confirmed in the 1964 Collins catalogue). Frequency selection via the Collins 313N-series control head (ARINC 410).

2. 51R-7A — VHF NAV Receiver

Introduction Date: c. 1970–1972 (Pro Line I)

VHF NAV receiver; 108.000–117.950 MHz (VOR and ILS localizer); Pro Line I generation. Frequency selection via 313N-4 series analog control (ARINC 410); also compatible with CTL-30/32 digital heads with CAD adapter. Typically paired with 618M-series COM in Pro Line I installations.

3. 51R-8A — VHF NAV Receiver

Introduction Date: c. 1972–1975 (Pro Line I, second generation)

Updated 51R NAV receiver; same 108.000–117.950 MHz coverage; same ARINC 410 wire tuning via 313N-4 series control head. The -8A suffix represents a design generation increment over the -7A. Both are available from Southeast Aerospace and other dealers.

4. VIR-30 — VOR Navigation Receiver

Introduction Date: c. 1970–1972 (Pro Line I)

VIR = VHF Instrument Receiver. Covers 108.000–117.950 MHz (VOR and ILS localizer). Dedicated NAV-only unit, preferred over the 51R-7A/8A for twin-NAV installations. Controlled via 313N-4 series analog control head (ARINC 410), or CTL-30/CTL-32 digital heads with a CAD adapter.⁹ Compatible with 3-wire synchro RMI using the 699Z-1 adapter.

5. 860E — DME Transceiver Series

Introduction Date: c. late 1963–1965 (Solid State System)

The 860E predates Pro Line I by approximately seven years, making it contemporary with the 618M-1 rather than a 1970s unit. It operates on the ICAO DME band (962–1213 MHz) and is tuned via the ARINC 568 two-out-of-5 code for DME, which is provided as an output from the same 313N-4D control head used for VHF COM/NAV (ARINC 410).

6. DME-40 — DME Navigation Transceiver

Introduction Date: c. 1970–1972 (Pro Line I)

Pro Line I successor to the 860E. Operates on the ICAO DME band (962–1213 MHz); provides slant-range distance, groundspeed, and time-to-station. Tuned via 313N-4D or CTL-30 VHF NAV control units:¹² the 313N-4D delivers the ARINC 568 DME channel selection output based on the VHF NAV frequency selected via its ARINC 410 interface. Companion IND-40 DME indicator from the same Pro Line I suite.

7. 51RV — Combined VOR / GS / DME / MB Receiver

Introduction Date: c. 1970–1975 (Pro Line I to early Pro Line II)

Combines VOR, glideslope (GS), DME, and marker beacon (MB) in a single LRU, replacing what previously required three separate units. Frequency selection via 313N-4 series analog control (ARINC 410); later variants also compatible with CTL-30/32 digital heads with a CAD adapter. Southeast Aerospace explicitly confirms ARINC 2-out-of-5 compatibility for the related VIR-31 family:¹³ the same applies to the 51RV series.

8. ARINC 410 — 2-Out-of-5 Wire Frequency Selection

8.1 What Is ARINC 410?

ARINC Characteristic 410 defines the 2-out-of-5 parallel wire code for frequency selection in airborne VHF communications and navigation equipment. In this scheme, for each decimal digit of the selected frequency, exactly two of five available wires are pulled to ground (negative active logic); the avionics unit decodes the combination to identify the digit (0–9 require five wires, since only C(5,2) = 10 combinations exist — one combination per digit). The Phoenix 2000 flight simulator community documents: “The interface on most radio heads uses a 2 of 5 code (negative active) which was defined in ARINC 410.”¹⁴

ARINC 410 was the universal airborne analogue frequency selection standard from the early jet age through the late 1970s for VHF COM and VHF NAV. The Collins 313N-series control heads (313N-2D, 313N-4D, 313N-5, 313N-5A) are the primary aircraft-side implementation. The Collins VHF-20 series documentation explicitly states: “Digital binary (2×5 wire) frequency selection as per ARINC 410.”¹⁵

8.2 ARINC 568 — The Companion Standard for DME

Jan correctly identifies ARINC 410 as the applicable standard for VHF COM and VHF NAV. A parallel standard governs DME channel selection. ARINC Characteristic 568 specifies the 2-out-of-5 code for DME tuning. In practice, the Collins 313N-4D control head provides both ARINC 410 (VHF COM/NAV) and ARINC 568 (DME) outputs simultaneously from a single panel installation. The Southeast Aerospace 313N-4D product page confirms: “Models available that provide channel selection for DME equipment utilizing two-out-of-five remote selector system per ARINC characteristic 568” and “Models available that contain isolation diodes to allow transferring between two control units without interaction in accordance with ARINC characteristic 410.”¹⁶

In summary: all units in Jan’s enquiry use the same 313N-4D control head, and all are therefore part of the same analogue 2-out-of-5 family — ARINC 410 for VHF COM/NAV, ARINC 568 for DME, both physically delivered by the same control head.

8.3 Collins 313N-Series Control Heads

8.4 ARINC 410 Compatibility — Complete Summary Table

8.5 Transition to ARINC 429 / CSDB Digital Buses

ARINC 429, the serial digital avionics data bus that replaced ARINC 410/568 parallel wiring, was published in 1977 and became standard on aircraft entering service from the late 1970s onwards.¹⁷ Collins introduced the CTL-20 and CTL-21 digital control heads (Collins Serial Data Bus, CSDB) and the CTL-30 (ARINC 429-compatible) to replace the 313N series on new installations.

Critically, the 313N-series (ARINC 410) heads cannot provide 8.33 kHz channel spacing, which is now mandatory in European airspace above FL195. Aircraft still equipped with 313N-series control heads require head replacement to operate in 8.33 kHz airspace, even if the underlying transceiver (618M-5A) supports 8.33 kHz.¹⁸

9. Summary Timeline — All Seven Units

HIGH = confirmed from contemporaneous primary source.   MODERATE = generation era confirmed; exact year estimated.   LOW = relative dating only; no primary date found.

10. Resolving Remaining Uncertainties

Jan’s assessment is correct: without advertising contracts or manufacturer archives, the LOW-confidence dates cannot be tightened further from open sources. He has himself already identified two of the most productive research tools (British Aviation Ancestry database; Collins Aerospace Museum brochure archive). The complete priority list:

• 1British Aviation Ancestry database (systematic search) — aviationancestry.co.uk — Collins 1960–1975 — Jan has already found the 1963 ad. A year-by-year review through 1975 would give market-availability lower bounds for each variant when it first appears in UK aviation advertising.
• 2Collins Aerospace Museum brochure archive — collinsaerospacemuseum.org/collins_brochures/ — Additional aircraft-type brochures from the 1960s and early 1970s will document which SSS and Pro Line I units were specified for each aircraft at the factory-fit stage and in what year.
• 3Aviation Week & Space Technology archives, 1963–1975 — Available via ProQuest Historical Newspapers at research libraries. The same type of annual equipment survey that appeared in Flying in November 1962 was also published in Aviation Week; systematic coverage would likely yield specific Pro Line I launch dates.
• 4Collins Collectors Association technical archive — collinsradio.org/cca-collins-technical-archives/ — Earliest-dated editions of the 51R-7A, VIR-30, DME-40, and 51RV service manuals provide precise lower bounds.
• 5FAA Historical TSO Records — FAA Aircraft Certification Service (AIR-100). TSO approval dates (TSO-C34, C36, C37b/C38b, C66, C35) are within 1–2 years of market introduction. Prefer over the Collins anniversary book for all equipment where both are available.

11. Collins Avionics Numbering Conventions

References & Sources

• Flying magazine, November 1962, p. 120 (Google Books ID: S-45uoS-v04C) — books.google.com. Source identified by Jan SP5XZG. Also reproduced at prc68.com/I/CollinsHSI.html. Primary source for January 1963 618M-1 and late-1963 DME dates.
• Collins aviation advertisement, 1963 — British Aviation Ancestry database (aviationancestry.co.uk), reference Avionics-Collins-1963-52126. Identified by Jan SP5XZG. Corroborates SSS equipment availability in 1963.
• Collins Jet Commander Avionics Catalogue, 1964 — Collins Aerospace Museum: collinsaerospacemuseum.org. Factory-fit confirmation of SSS avionics in 1964 production. Identified by Jan SP5XZG.
• Southeast Aerospace, Collins Pro Line I product notes (618M-2B, DME-40, VIR-30A, 51R-7A, VIR-31A, 313N-4D, 313N-5) — seaerospace.com. Confirms “early 1970s” Pro Line I manufacture; documents ARINC 410/568 compatibility for each unit; 313N-4D isolation diodes per ARINC 410 and ARINC 568 DME output.
• Collins VHF-20 documentation — tsc-60.cellmail.com. Documents “Digital binary (2×5 wire) frequency selection as per ARINC 410.” TSO: C34a, C36a, C37a, C38a, C40a, C66.
• Phoenix 2000 Flight Simulator, ARINC 410 reference — phoenixcomm.wordpress.com. Confirms 2-out-of-5 negative-active logic definition per ARINC 410.
• Radiomuseum.org, Collins 618M-1 — radiomuseum.org/r/collins_618m_1.html. Build date 1963.
• Rockwell Collins — Wikipedia — en.wikipedia.org/wiki/Rockwell_Collins. Merger date 2 November 1973.
• Collins Radio Company Records, University of Iowa — lib.uiowa.edu.
• Collins Collectors Association technical archive — collinsradio.org.
• Collins Aerospace Museum brochure archive — collinsaerospacemuseum.org/collins_brochures/.