747FOCAL's memory serves us well. The conversion of a three pilot cockpit to a two pilot cockpit was around in the mid 90s – probably 1996/7. I don't know if it made it to STC status but a fair bit of work was done on it. Richard Taylor and Ed Smith got a patent on it. I think it might have been based on something by Richard Shipman in "727: The New Look" in Air Line Pilot, Sep. 1988.
The original type certificate for the Boeing 727 was issued under the CAR 4B Rules, which required redundancy in critical aircraft systems, but not to the extent of requiring fail-safe operation of these critical systems as currently defined by the FAA, the fail-safe level being defined in "Part 25" of the Rules. Substantial modifications to the 727's systems invoke Part 25 of the Rules, which require conversion of those critical systems to a fail-safe level of operation - extremely expensive.
All glass cockpit solutions, involving software associated with the CRTs, required FAA oversight under Part 25 of the Rules, requiring the certification applicant to prove fail-safe operation of all software to a determined level of probability. In short, unless the majority of the supplemental type certificate (STC) observation and documentation procedures could be conducted under CAR-4B rules, the unit costs associated with aircraft modification are driven up to the point that the investment in the supplemental type certificate (STC) for the Boeing 727 cannot be returned. So they set out to make a CAR-4B conversion.
They relocated instrument controls from the flight engineer's instrument panel to positions in the cockpit closer to the remaining two pilot air crew, so the relocated instruments were accessible for monitoring and operation by the two pilot air crew. Although they make use of stored programme computers, they did not involve a "glass cockpit" type of conversion with CRT-based displays, thus avoiding the significant costs involved in the creation of the substantial software required to achieve the reading and conversion of analog control inputs/outputs for display on the CRT screens. Since no existing aircraft systems were changed, the STC could be under the CAR-4B rules of certification.
The installation of the conversion was claimed to be doable in less time than a week. The flight engineer's control panels were relocated to an extended overhead panel added between and over the captain's seat and the first officer's seat, and to a first officer's auxiliary panel mounted to the cockpit bulkhead adjacent the first officer's seat. All relocation of flight engineer instrument panel instruments was done without modification to the aircraft systems except to the fuel panel, the electrical panel, and the environmental control systems panel. The fuel panel, electrical panel and environmental control systems panel were modified to be more compact and include partial automation of these systems to reduce crew member workload. A master caution system was installed in the cockpit to monitor irregular and critical warning indicators out of the direct line of sight of the two crew members. In order that the two crew members not leave their seats during a landing gear extension failure, a mechanism provided gear extension capability from a seated captain or first officer's position.
