LEARJET 35 COCKPIT INSTRUMENTS
The Horizontal Situation Indicator (HSI) is a combination of the Heading Indicator which is located just below the Artificial Horizon (AH). This instrument shows more information than the use of the individual types of instruments. The combinations comprises with the magnetic compass, navigation signals and a glideslope. This would give the pilots an indication of the location of the aircraft with relationship to the chosen course. This instrument is a replacement of the Heading Indicator (HI) which is found in the Learjet 35.
Horizontal Situation Indicator
How It Works
Actual Location of HSI in LearJet 35 @ The ARCH
The instrument functions the under the principles of the Course Deviation Indicator (CDI) with all the necessary importance which is the “TO/FROM” indicator, Course select point and also the Course select knob. The course deviation bar operates with a VOR navigation receiver to indicate left or right deviations from the course selected with the course-indicating arrow.
Advantages of Combining
Combinations is actually to reduce the stress levels of the pilots as they would need to concentrate at too many instruments at once and came the HSI which helped the pilots. This has also helped airplane manufactures in the cockpit design to free up more space for new types of instrument for the coming years.
Heading Indicator
Heading Indicator also known as the Directional Gyro used in an aircraft to inform the pilot of the aircraft's heading with respect to Magnetic North and it also provides a visual reference points which helps the pilot to maintain the aircraft course as well as to give an accurate turn in new heading.
How It Works
The heading indicator principle works using a gyroscope tied by an erection mechanism.It is subject to drift errors (called apparent drift) which must be periodically corrected by calibrating the instrument to the magnetic compass.
VHF Omni-Directional Range (VOR)
The VOR system is well known as to provide magnetic bearing information to and from the station which is also being used in the Course Deviation Indicator (CDI) for navigation. The prefix “Omni” means all and an omnidirectional range is a Very High Frequency (VHF) radio transmitting ground station the projects straight line courses or radials from the station in all directions.
How It Works
The standard VHF frequency is 30 MHz – 300 MHz but for the VOR, the frequency that is used is 108.0 MHz – 117.95 MHz. The VOR course or radials are always projected from the station and it is referenced to magnetic north. This would make a radial defined as a line of magnetic bearing extending outward from the VOR station.
Radials have its own identification numbers beginning with 001 which would be 1° east of magnetic north. This would the progress in sequence through degree of a circle reaching 360°. To aid this orientation, the compass rose reference to magnetic north is superimposed on aeronautical charts at all station locations.
VOR on Board Aircraft
Advantages
VOR Ground Station
Disadvantages
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More accurate, precise flying
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Reliable
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Not susceptible to interference (Weather Conditions)
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Voice Capable
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Costly to maintain
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Line-of-Sight Restrictions
Types of Navigation Instruments used with VOR
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Course Deviation Indicator (CDI)
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Horizontal Situation Indicator (HSI)
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Radio Magnetic Indicator (RMI)
Glideslope
An Instrument Landing System (ILS) is a ground-based instrument approach system that provides precision horizontal guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and in many cases high-intensity lighting arrays to enable a safe landing during bad weather conditions.
How It Works
The glide path works in a similar way to the localizer with its signals operating at Ultra High Frequency (UHF) range, modulated at 90 Hz and 150 Hz. The 90 Hz gives a 'fly down' indication and the 150 Hz 'fly up'.
Needle indicates above/below glide path.
Centered Needle = Correct glidepath