Perhaps many pilots have difficulty with raw instrument flying when using glass display formats.
A short, limited history of the development of ‘glass’ instruments (including LCD, LED, etc) indicate that there have been many weaknesses with tape formats in comparison with conventional dial instruments. The reappearance of dial formats on the larger ‘glass’ displays perhaps reinforce this point.
Instrument formats with glass were initially constrained by the size of the equipment and computing power. A simple ‘look-alike’ attitude display provided an easier certification route for an untested technology. There were also parallel needs in computation for reliability and avoidance of ‘hazardous / misleading’ information; techniques such as dual-dissimilar hardware and software were used. This latter area and display media have progressed rapidly in the last 20 yrs.
Wider displays enabled a tape format for airspeed; there was significant debate about the direction of the numbers, but the increased use of FD/autopilot/throttle was argued to balance any ‘human factors’ concerns (speed/pitch/control convention). Note that those aircraft which initially did not have autothrottle chose an alternative orientation – Gulfstream high numbers down; IIRC many manufacturers gave operators the choice, but none strayed from the norm.
Automation may hide these weaknesses, but they are still there; try a non-autothrottle, non FD night/IMC takeoff (as per the MEL), with an engine failure +- V2.
Research evaluated alternative formats; a nonlinear scale to give a wider view of the speed range, a curved scale to aid rate (acceleration) information, but none were really convincing.
The mandated Vmo/Mmo markings were supplemented with AOA computation to improved low speed awareness as did a range of bugs for ‘command’ or temporary limit speeds. A trend vector was added to aid acceleration (a crutch), and there were suggestions that it could be used as a ‘director’. Some formats might still be used in this way in lieu of AT. There were also issues about the direction of acceleration in a stall with trend vectors using an airspeed/inertial mix – aircraft speed decelerating but with inertial acceleration Earthwards! (cf AF447)
Many of these basic deficiencies are seen in early altimeter formats which became available with the larger (square) displays. Research again focused on dial formats including ‘egg’ shapes to improve the much deficient rate information deemed important in acquiring and maintaining altitude (“ … difficult to maintain altitude awareness while flying manually.”).
Note that glass VS (alt rate) formats also suffered; some VS formats change the indicator’s point of rotation at high VS to accentuate the value, they also use numerals and colour change to supplement the reduced analogue cues.
The key features in the difference between tape and dial formats are the lack of angular awareness of a moving pointer (including high speed = high, etc), the reduced length of the display scale, the swept area (dial airspeed, MD 80 anyone?).
Altitude formats need a counter pointer system; this required some of the new computation techniques such as dynamic widowing – larger displays and more computing power = cost, thus initially a compromise.
The altitude deficiencies have been slowly eroded with ‘crutches’, such as the shape of the ‘set bug’, with chevron/diagonal structures which aid detection of small movements, differing size of tape scale markings and colouring, and additional bugs (and even an alt trend vector?).
These appear to have improved the general performance of the displays to meet the industry’s requirements for monitoring automated flight.
However for manual flight, together with reducing experience in raw instrument flying, and perhaps without specific instrument flight training on tape displays (weaknesses in alt / attitude / speed scan), the height-keeping accuracy may be degraded, or at least a more demanding task which increases workload.