BOEING 707 circa 1970 panel - Basic Flight Instruments

The Airspeed and Mach Indicators

Airspeed indicatorThis airspeed indicator includes a digital Mach readout, which is activated above Mach 0.4. The "V" icon above the ASI opens a popup window displaying V-speeds for take-off and landing. 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 is not equipped with an autothrottle.

Image of altimeter

The Altimeter

This panel's altimeter has a digital reading of the entire altitude, by means of rotating drums. 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.

Radio altimeter
Image of RMI

The RMI

This instrument, located below the Airspeed Indicator, has two switches, permitting the needles to be switched between pointing to the VOR, or the ADF.

The DME

Below the Vertical Speed Indicator, there is a readout for the distance to DME 2 (the DME 1 readout is on the HSI).

DME

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.

Clock

Altitude Alerter

The altitude alerter is used as a reminder of assigned flight level. On approaching the selected altitude, a tone sounds and a light comes on on the altimeters when 700 feet away. The light also comes on (and the tone sounds) if deviating more than 300 feet from the selected altitude. The Altitude Alerter is not an automatic altitude capture function - one must manually level off when reaching an assigned altitude! .Altitude alerter

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.
Image of ADI

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

Image of HSI

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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