14 CFR § 29.1321

Each flight, navigation, and powerplant instrument for use by any pilot must be easily visible to him from his station with the minimum practicable deviation from his normal position and line of vision when he is looking forward along the flight path.

Each instrument necessary for safe operation, including the airspeed indicator, gyroscopic direction indicator, gyroscopic bank-and-pitch indicator, slip-skid indicator, altimeter, rate-of-climb indicator, rotor tachometers, and the indicator most representative of engine power, must be grouped and centered as nearly as practicable about the vertical plane of the pilot's forward vision. In addition, for rotorcraft approved for IFR flight—

The instrument that most effectively indicates attitude must be on the panel in the top center position;

The instrument that most effectively indicates direction of flight must be adjacent to and directly below the attitude instrument;

The instrument that most effectively indicates airspeed must be adjacent to and to the left of the attitude instrument; and

The instrument that most effectively indicates altitude or is most frequently utilized in control of altitude must be adjacent to and to the right of the attitude instrument.

Other required powerplant instruments must be closely grouped on the instrument panel.

Identical powerplant instruments for the engines must be located so as to prevent any confusion as to which engine each instrument relates.

Each powerplant instrument vital to safe operation must be plainly visible to appropriate crewmembers.

Instrument panel vibration may not damage, or impair the readability or accuracy of, any instrument.

If a visual indicator is provided to indicate malfunction of an instrument, it must be effective under all probable cockpit lighting conditions.