This model breaks away from the conventional design of placing an aviation slide rule on a rotating bezel, instead incorporating a rotating ring inside the case and keeping the exterior as simple as possible. This design became the foundation for subsequent PROMASTER pilot radio-controlled watches and has been carried on for many years.
It was also the first time that the reception function display for the radio-controlled watch was shown at the "tail" of the second hand, and that a double-layered dial was used for the Eco-Drive, attempting a dial design with a large visible area. These design techniques, now standard, originated with this model.
Even though the dial could easily become cluttered with elements like the slide rule and minute track, the use of Arabic numeral indexes at 12 and 6 o'clock makes the time easy to read.
The case design expresses a stripped-down, functional beauty without waste. The dial design skillfully conveys both legibility and a sense of precision. By combining a titanium exterior treated with MRK processing, Eco-Drive functionality, and radio-controlled features, the watch is light, scratch-resistant, never stops, and never loses accuracy, providing true practicality for users.
This is a model where technology is brilliantly elevated through design, and its influence on CITIZEN's design philosophy is truly significant.
Each part is given a sharp edge, creating a clean overall impression, while details such as aligning the ridge lines of the lugs and end pieces show a high level of attention to detail and a refined design.
The dial design is also full of precision, reminiscent of an instrument panel.
The case and band use titanium treated with Duratect MRK, resulting in a scratch-resistant and robust design characteristic of PROMASTER.
The side surface of the case features a reverse taper shape, which is a distinctive feature of this model. The surfaces are composed in a crisp and clean manner.
The side of the lug features a separate "lid"-shaped part. While it does not serve a particular functional purpose, it gives an impression of strength and durability.
The case back has a sharp, clean shape with edges. The earth mark is placed at the center, surrounded by the brand logo and other markings. The design conveys a sense of reliability without unnecessary decoration.
The band design is clean and simple, with two polished lines on the center links. The cross-section of the links is shaped to evoke the cross-section of an airplane wing.
The dial design, characteristic of a pilot watch with an aviation slide rule, exudes precision. All twelve indexes have luminescence, ensuring visibility in the dark. To laminate two dials, an opaque printed section is required on the upper dial. By setting the inside diameter of this opaque section near the outside diameter of the minute track, the color difference is minimized—a key point of this model's dial design.
The luminous paint is applied thickly, resulting in high brightness when glowing. The use of Arabic numerals at 12 and 6 o'clock makes it easy to read the time.
A highly approachable design.
A layout devised to display the radio-controlled reception function at the "tail" of the second hand. It is neatly integrated into the dial layout.
A large, knurled crown with a diameter that makes it easy to operate.
ENGINEER'S EYE
Where Wings Begin
This is a pilot watch that embodies the ruggedness characteristic of the PROMASTER line, with its exterior finished using CITIZEN’s surface-hardening technology, DURATECT MRK.
It was the first full-metal radio-controlled model to adopt an internal rotating ring. I remember that this ring component initially failed to meet the dimension precision and had to be remade multiple times. We also designed a new cross-section for the metal band for this model.
Since then, the bands for radio-controlled pilot watches have followed this design. Inspired by an airplane wing cross-section, the band has a highly intricate cross-sectional shape. Although there were many difficult adjustments, it has continued to be used for a long time afterward and became a technology development that plays an important role.