ILS vs. RNAV, VOR, and LOC: A Pilot's Perspective on Landing Systems

Introduction to Landing Systems

When it comes to landing systems used in aviation, Instrument Landing Systems (ILS) are one of the most critical and commonly utilized. However, it's important to understand that not all pilots encounter an ILS every day, as they rely on a variety of systems depending on the airport's infrastructure and the pilot's needs. This article explores how often pilots use ILS, and compares it with other forms of landing aids such as RNAV, VOR, and LOC in real-world scenarios.

The Regularity of ILS Usage

When an airport has an Instrument Landing System (ILS), it is almost a requirement for almost all airline pilots to use it. The Federal Aviation Regulation (FAR) 121 mandates that pilots shall not descend below the glide slope if a glideslope is available. Thus, pilots almost always land using an ILS, unless there is a VOR or other form of navigation available.

Pilot Experience and Certification

Most pilots, except for those with advanced certificates such as Private, Commercial, or ATP, are not instrument-rated. This means that they primarily use visual approaches, either when instrument conditions clear up or when flying under Visual Flight Rules (VFR).

Instrument Equipped Aircraft

Even if pilots are instrument-rated, not all aircraft are equipped with the necessary avionics to fly the published instrument approach. Therefore, the usage of ILS is dependent on the availability of such equipment and the pilot's proficiency.

Alternative Landing Systems

When an ILS is not available, many pilots have to rely on other systems to safely land their aircraft. These include:

RNAV

Radiative Navigation (RNAV) is a type of navigation that uses satellite systems to guide pilots to their destination. RNAV is very common, second only to ILS. Pilots may choose RNAV for its flexibility and precision, even when an ILS is not present.

VOR (VHF Omnidirectional Range)

VOR is a legacy navigation system that has been in use for decades. It is still a viable alternative for pilots to use when an ILS is not available. However, due to its older technology, VOR may not offer the same level of precision as RNAV or ILS.

LOC (Localizer)

Localizer (LOC) is a ground-based system that guides aircraft along a horizontal path to the runway. It is often used in conjunction with a VOR or as a backup system. LOC is less precise than ILS or RNAV but is still a reliable option.

Student Pilots and Emergency Landings

Student pilots, who are not fully certified, can also request a practice approach under Visual Flight Rules (VFR) to familiarize themselves with the procedures. However, a safety pilot or Certified Flight Instructor (CFI) or CFII must maintain visual traffic awareness during such a practice.

In emergency situations, student pilots can be cleared for an emergency approach, which may involve radar and altitude suggestions from the controller. However, this is rarely done due to modern advancements in technology and safety protocols. Ground Control Approach (GCA) is a system used in movies where a controller tracks both heading and altitude; however, it is no longer commonly used, except in very rare cases.

Conclusion: ILS Usage and Alternatives

While Instrument Landing Systems (ILS) are the primary and most reliable method of landing, they are not available at every airport. Pilots often use RNAV, VOR, or LOC as alternatives. The choice of landing system depends on the specific circumstances and requirements of the flight.

The key takeaway is that the use of ILS is significant but not universal, while RNAV, VOR, and LOC form a comprehensive backup system, ensuring safe and efficient landings in a variety of conditions.