BOEING 707-420 panel - Basic Flight Instruments

The Airspeed and Mach Indicators

The Boeing 707 airspeed indicator has a slightly different scale to the ASI in the default 737, and this panel reflects this. You may also note that the instrument has no digital readouts whatsoever. The airspeed indicator contains a speed bug which may be useful as a reference when taking off or landing. However, the only place on the panel where the speed bug has an effect is the Fast/Slow gauge on the ADI - the 707 has no autothrottle.

Since there is no Mach reading on the ASI, a separate Mach meter is required - it is located below the Turn Co-ordinator.

| The Altimeter This panel's altimeter displays a digital reading of the entire altitude, by means of rotating drums (In 707s from a few years earlier, only the thousands were displayed numerically). The gauge also displays its pressure setting by means of numeric drum readouts, in both imperial and metric units.

The Radio Altimeter This instrument indicates the aircraft's height above the ground, and is useful for judging the approach to the ground when landing. The instrument reads as far as 2,500 ft, and contains an adjustable Decision Height bug - when the decision height is reached, the DH light on the ADI will come on momentarily. |

| The RMI This instrument on the Captain's panel has two switches, permitting the needles to be switched between pointing to the VOR, or the ADF. Directly below the RMI is the DME 2 readout, giving the distance to the NAV 2 beacon. The distance to the NAV 1 beacon is given on the HSI.

The DME Below the RMI, there is a readout for the distance to DME 2 (the DME 1 readout is on the HSI). |

| The Turn Co-ordinator This instrument is in some ways a hangover from the instrument panels of piston-engined aircraft - the needle indicates the rate of turn, while the ball indicates slipping or skidding of the aircraft. If you have Auto-Coordination switched on, the ball will always be centred.

The Clock The 707 is fitted with an analogue clock with hour, minute and second hands. To adjust the clock, there is a knob at the lower right which increments/decrements by 1 minute per click. When passing through zero, the hours change accordingly, as with a real analogue clock. However, to speed up setting time, there is an extra knob at the lower left which adjusts hours directly. Note the small inset clock above the main clock - this reads Zulu Time. |

| The Flight Control Positions Indicator This instrument, located on the First Officer's panel, indicates the position of the flight controls. When the control column or autopilot are commanding a roll to the left, the aileron position indicator rolls right - this symbolizes the movement of the ailerons up on the left hand side of the aircraft, and down on the right hand side.

The ADI

This ADI layout was used on most US-built airliners from the mid-60s up until the 1980s, when EFIS computer displays began to take over. In addition to the attitude indicator, the ADI contains the following components: Fast-Slow Gauge- to the left of the attitude indicator this indicates the aircraft's airspeed, relative to the speed selected with the airspeed bug. Each dot on the scale represents 10 knots. Localizer and Glideslope indicators - located below and to the right of the attitude indicator respectively, these indicate the aircraft's position relative to an ILS beam. This information is also available on the HSI. Decision Height Light - comes on momentarily when descending through the Decision Height. Flight Director - allows the autopilot to give commands to the pilot, rather than flying the aircraft directly. This is integrated with all of the autopilot's modes, but is most useful during the landing approach. |

The presentation of various types of information in one location makes the ADI helpful when carrying out an instrument approach and landing.

| The HSI The HSI has the standard layout for pre-EFIS jet aircraft. Note the setting knobs on the instrument - the left one sets the OBS course, while the right one sets the target heading for the autopilot (newer aircraft models have these controls in the autopilot on the glareshield). The instrument also has numeric readouts for the current OBS course, and DME 1.

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