What is localiser back course?
What Is A “Back Course” Approach? When you fly a localizer back course approach (LOC BC), you’re navigating to the runway using horizontal guidance off of a localizer system, but in the opposite direction that you’d normally use the localizer.
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When flying a localizer back course approach using an HSI which course should be set in the OBS?
Rule #1. Always (always!) put the localizer inbound front course under the omni-bearing selector (OBS). The OBS setting doesn’t matter to the electronics on a localizer, but this is a good rule as we’ll see a bit further down.

How do you prevent reverse sensing on the localizer back course?
Reverse sensing occurs inbound on the back course and outbound on the front course. With an HSI, you can avoid reverse sensing by setting the published front course under the course index. This applies regardless of your direction of travel, whether inbound or outbound on either the front or back course.
Does an ILS have reverse sensing?
But no, it would not result in reverse sensing due to the fact that the ILS system is only capable of sensing whether it is receiving more of the 90 Hz signal as opposed to the 150 Hz signal and interprets this as either above or below glideslope. It cannot differentiate between erect and inverted flight.

How do you do a back course?
Flying a Back Course | LOC/DME-E KASE Aspen | Reverse Sensing
What does half bank mode do?
Half bank mode reduces the maximum commanded bank angle to 15 degrees.
What is the difference between a CDI and HSI?
A standalone CDI (Course Deviation Indicator) is an instrument that shows your deviation from a VOR radial that is selected using the OBS (Omnibearing Selector) knob located on the instrument itself. An HSI (Horizontal Situation Indicator) is an entirely separate instrument that combines a CDI and a heading indicator.
What does slaved HSI mean?
Horizontal Situation Indicator
The ST-180 Horizontal Situation Indicator (HSI) system combines a magnetically slaved gyroscopic compass with a VOR/Localizer and glideslope display. The resulting instrument display provides the pilot with a pictorial of the aircraft position and heading relative to the selected VOR/GPS or Localizer course.
How does HSI correct reverse sensing?
When using traditional ILS/LOC instrument, the needle moves right when it senses more of the right signal, but since the signal is now on the left, you get reverse sensing. On the HSI, the needle still moves right when it senses more of the right relative to the arrow when it senses more of the right signal.
Why is localizer more sensitive on back course?
Because you are closer to the localizer antenna, the course information is more narrow and can seem “sensitive.” Just don’t forget the switch that allows the flight director to get its mind right about the front course versus the back course.
What if glideslope fails on ILS?
If you fail your glide path indicator (put a sticker on it) and you are – for any reason – not visual with the runway at your minimums passing the DTL go around, do not change back to the ILS.
What is an LDA approach?
Definition. Localiser (LOC) and Localiser Type Directional Aid (LDA) Approaches are defined as non-precision runway approach aids based on a single ground based radio beam which provides pilots with horizontal guidance during an approach to land.
Why do jets stall at high altitude?
At high altitudes swept wing turbojet airplanes may stall at a reduced angle of attack due to Mach effects. Pilot Tip Stall recovery requires that the angle of attack must be reduced below the stalling angle of attack. The elevator is the primary pitch control in all flight conditions… not thrust.
What is 0.3 g buffet margin?
1) The certification regulations require that throughout the flight envelope, up to MMO, irrespective of the weight, the aircraft must have a buffeting margin of 0.3 g. This means that a load factor of 1.3 g must be attainable before “buffet onset” is encountered.
What is the lubber line on an HSI?
Lubber line represents the current aircraft flying direction. The HSI illustrated above is a type designed for smaller airplanes and is the size of a standard 3 1⁄4 inch instrument. Airline and jet aircraft HSIs are larger and may include more display elements.
How many degrees are each dot on an HSI?
Each dot on the deflection scale represents 2° of deviation. Thus, a full-scale lateral deflection represents a deviation of 10° or greater.
How do you read HSI indicator?
Horizontal Situation Indicator Explained | HSI Test Questions
Does ILS need outer marker?
An Outer Marker (OM) or suitable substitute (refer to subparagraph 9c and Appendix A) is only required to indicate the final approach fix (FAF) for Nonprecision Approach (NPA) operations (i.e., localizer only). The FAF on CAT I/II/III ILS approach operations is the published glideslope intercept altitude, not the OM.
How much more sensitive is a localizer than a VOR?
four times
Localizer specs
Localizer course widths range between 3º and 6º. The specific angle chosen puts the course width at the runway threshold at about 700′. Typically, this is a 5° total width (or 2.5º full deflection to each side), four times more sensitive than a VOR.
Is middle marker mandatory for ILS approaches?
b.
Middle Marker (MM) beacons are not required for CAT I/II/III ILS.
Do you need DME for ILS?
An ILS never requires DME for identifying the FAF or DA because the FAF is glideslope intercept and DA is by altitude. Cross-check of glideslope intercept altitude is a good idea, but it’s never required. The missed approach goes to STOAS, but that can be identified as an intersection of two VOR radials.
What is the difference between an LDA and ILS?
As a “directional aid”, and only a Category I (CAT I) approach, rather than a full-fledged instrument landing system (ILS), the LDA is more commonly used to help the pilot safely reach a point near the runway environs, where he or she hopefully can see the runway, at which point he or she will proceed and land visually …
What is TORA TODA ASDA LDA?
Simply put, clearway, stopway, TORA (Take off Run Available), TODA (Take off Distance Available), ASDA (Accelerate Stop Distance Available) and LDA (Landing Distance Available) are specific parts and extensions of a runway, which is basically the area used for the landing and takeoff of an aircraft.
What altitude is coffin corner?
Flight 447 was also flying at a cruise altitude of 35,000 feet, an altitude where the relationship between an aircraft’s stall speed and the speed of sound has gained the name “the coffin corner”.
Why is Mach tuck so important to the coffin corner?
The aircraft can literally nose over even though it is very fast. This is known as the “mach tuck”. At a specific altitude accurately called the “coffin corner”, the aircraft becomes essentially uncontrollable.