1. Where do we find RVSM airspace? Higher cruising altitudes.
2. What happens in RVSM airspace? Airplane separation is reduced vertically.
3. Why does RVSM airspace exist? To allow more aircraft in the sky.

There you have it... the simple definition of RVSM. Now, let's get technical:

RVSM stands for Reduced Vertical Separation Minima and it's located between FL290 (29,000ft) until FL410 (41,000ft) inclusive. To understand RVSM, you must first understand what the vertical separation requirements were above FL290 before 2005. Prior to RVSM, aircraft were required to be separated by 2,000 feet vertically above FL290 due the possibility of altimetry errors at the higher flight levels. RVSM airspace allows for a reduction in vertical separation between qualifying aircraft in order to allow more aircraft to operate in crowded enroute airspace thereby allowing for more efficient traffic flows. Airplanes of course move a lot faster at higher altitudes though, so it is only natural that this little amount of separation may make even the most vigilant pilot a little nervous. However, it is important to note that before implementing RVSM, aviation authorities instituted a required set of parameters that must be met in order to operate in RVSM. If any of these parameters cannot be met before entering or while operating within RVSM airspace, the aircraft is required to advise ATC and exit RVSM.

Before we get into other details about RVSM lets recall that in many countries, the East ODD and West EVEN rule applies to vertical separation. This practice ensures that two airplanes are never assigned the same altitude flying in opposite directions. In some regions that are geographically more north/south split such as Italy or Florida for example, they have elected to modify the rule to favor North ODD and South EVEN as the determining factor for vertical separation. Either way a region chooses to separate traffic, it is important to recognize that these rules exist are crucial to establishing a baseline for high altitude vertical separation.

Now that we have covered the basic rule for opposite direction vertical separation, let's talk about what makes an aircraft RVSM approved. In order for an aircraft to operate in RVSM airspace, a certification is required from the governing agency of that nation (FAA, local CAA's, etc.), but the basic equipment that an aircraft should have operational include: an autopilot, two independent altimeters, a transponder with an altitude reporting capability, and an altitude alerting system. During flight in RVSM airspace, pilots will cross check their two independent altimeters to ensure the difference does not exceed a specified tolerance, which could range anywhere between 50ft to 200ft.  If any of these items malfunction during flight in RVSM airspace, notification to air traffic control is essential.

Let's talk about air traffic controller's responsibilities in regards to RVSM airspace. Aircraft will have an equipment code in their flight plan assuring ATC that they are RVSM compliant and capable. If an aircraft alerts that they are no longer RVSM capable, ATC will have to either ensure separation of 2,000ft with that aircraft at all times or descend the aircraft outside of RVSM (below FL290).  However, just because an aircraft is not RVSM capable does not mean they can never fly between those altitudes. Many corporate jets are not RVSM capable but still request to cruise above RVSM airspace (e.g. FL430). In this scenario, the controller will climb the aircraft through RVSM airspace while ensuring 2,000ft separation is maintained between other traffic at all times. 

On a final note, RVSM aircraft require a maintenance certification as well. The next time you start up your flight sim and connect to POSCON for your online flight simulation experience, take a look at the outside of your aircraft. Depending on the quality of the aircraft in terms of realism and study level, you should see what's called an RVSM critical area (see image to the right). Aircraft maintenance technicians must run specific tests and certify that everything located within this box meets the required RVSM tolerances, which are often stricter than in flight checks accomplished by pilots. Static ports, pitot tubes, and AOA vanes are small examples of what can be found in these boxes, of course, these are important functions that will assure RVSM tolerances when in flight. Pilots check this box during preflight inspections to ensure this critical area is free of residue, damage, dents, or other non-normal appearances on the components in the boxed lines.

On POSCON, our air traffic controllers are well trained on RVSM procedures. When flying online, ensure your aircraft is RVSM capable and make sure you indicate it properly in the flight plan equipment code section ("W" is the letter identifying that the aircraft RVSM capable). If you do not include "W" and are offered an RVSM altitude (it happens), simply say to ATC "Negative RVSM". And of course if you are having issues with your autopilot, now you know you are required to tell air traffic control.

After reading this article, you should be confident answering when and why the "W" equipment code is required in your flight plan. It is true, there are far too many acronyms in the aviation world, but at least you got RVSM down! See you on POSCON in RVSM and don't forget the whiskey! (get it?)

Flying VFR is one of the first things you learn as a pilot; in fact, until you begin instrument training, the majority of your flights will be conducted under VFR or Visual Flight Rules. VFR does not require you to follow a route or fly an instrument approach to land. You can fly whatever direction you want, provided you are complying with all applicable rules. 

First and foremost, before you can fly under VFR, you need to have the correct tools at your disposal. The main tool you need is a sectional chart. These charts are issued as hard copy, large scale maps by the FAA every 6 months for less than $10 a print but with today's technology you can easily access a sectional chart online for free by clicking here. When you navigate to this website, you will see a large map; make sure to click on "World VFR" in the top right corner.

A sectional chart contains many different symbols, airspace boundaries, navigational aids, airways, and more. It can seem extremely overwhelming at first, but in time reading these charts will become completely natural. An easy way to quickly become familiar with how to read a sectional chart is to reference the legend which can tell you what all the symbols and colors mean. The expanded version of the legend contains a lot of great information for new pilots and you can find that here, but if you want the condensed legend you can find that here.

The second major obstacle to flying VFR is learning how to properly fly the traffic pattern. The traffic pattern is the rectangular course that is used by aircraft that are flying within the vicinity of an airport for the purpose of completing a full stop landing, practice touch and goes, or departing the airport on a long cross country flight. There are 5 legs of a traffic pattern, Upwind (Departure), Crosswind, Downwind, Base, and Final. Another important factor pilots must consider is the direction of the traffic pattern; Left or Right. These 5 legs are extremely important to know because when you are flying on the POSCON Network at an uncontrolled field (an airport without a staffed tower), you will need to announce your location on the CTAF (Common Traffic Advisory Frequency). This also applies to when you are flying inbound to a towered airport; however, the air traffic controller will give you a leg of the pattern to enter depending upon the configuration of the airport at the time. If you do not know your traffic pattern legs, you could easily cause conflicts with other planes operating in the same airspace.

Many new pilots get overwhelmed learning the traffic pattern. The specific factor that trips up many pilots is the left versus right traffic. An easy way to know if you are making left or right traffic is to determine where the runway is relative to your aircraft. If you are on a crosswind leg and you see the airport is to your left and slightly behind you, that means you are making left traffic.

Now, the obvious question, 'How do I know when to make left or right traffic?' For that, you would consult your sectional chart. If you take a look at the second image in this blog post, you will see 3 uncontrolled airports: Old Bridge (3N6), Trenton-Robbinsville (N87), and Monmouth Exec (BLM). Look at Trenton Robbinsville; you will see at the bottom of magenta text the letters RP 29. RP stands for Right Pattern. That indicates to pilots that if you plan on landing on Runway 29, it is a right-hand traffic pattern. Now look look at Monmouth Executive and notice there is nothing under all the magenta text. That is because the FAA made it a standard that if an airport does not specifically designate a runway as right pattern, it is assumed to be left hand traffic pattern.

When flying in the traffic pattern you should always maintain 1,000 feet AGL (Above Ground Level) as a piston aircraft. If you are in a jet or turbo-prop aircraft, you should maintain 1,500 feet AGL as your TPA (Traffic Pattern Altitude). To determine your TPA, you would again refer to your sectional chart and look for a bold italic number. This number indicates the airport elevation in MSL (Mean Sea Level) i.e. above sea level. If you take a look at BLM, you'll see an airport elevation of 153' MSL. In this case the TPA for piston aircraft is 1,153' MSL and the TPA for jet/turboprop aircraft is 1,653' MSL. Remember your altimeter is always set to MSL not AGL.

When flying in the traffic pattern on the upwind or departure leg, you should always turn your crosswind 300 feet BELOW TPA. So, if we are flying a pattern in BLM in a Cessna 172, we should be turning crosswind at 853' which is 300' below our TPA of 1,153'

When entering the traffic pattern on the 45 degree to downwind entry (see first image), you should try to plan your descent to be level TPA upon reaching the downwind leg. If you need to enter the traffic pattern from the opposite side of the pattern, you will need to execute an overflight of the airport at 500' ABOVE TPA. Once you overfly the airfield, continue outbound and start your descending teardrop entry turn to enter the 45 degree to downwind entry leg of the pattern. You should practice the overflight teardrop pattern entries as they can be tricky when the winds aloft are strong. An example of an overflight teardrop entry can be seen here. This was a flight I did when MJX (Ocean County) winds favored runway 32 and a Piper Seminole was already in the pattern.

The third step, and arguably the most important, is your communication on CTAF. First, we need to know the frequency to use. If you look at the sectional chart again, the frequency that is left of the filled circled "C" is your CTAF frequency. On POSCON, the pilot must determine which frequency to broadcast on using the following order: 

1. Refer to published charts for the CTAF frequency.
2. If you are at a typically towered airport with no ATC online, and there is no published CTAF, then refer to the POSCON Airport Advisory chart for that airport. In most cases, we have specified a frequency for you to tune to.
3. Use 122.95 if the previous 2 steps do not provide you a frequency.

Most uncontrolled airports have another frequency that is equally important to flying traffic patterns and that is the ASOS/AWOS frequency. ASOS is short for Automated Surface Observing System and AWOS is short for Automated Weather Observation System. For all intents and purposes, these two systems do the same thing - they give you an automated relay of the METAR (METeorological Aerodrome Report) for a particular airfield. POSCON plans on having ASOS/AWOS stations operational at all applicable airfields, so pilots should always tune into the ASOS/AWOS frequency and gather current weather conditions before conducting any air operations. These reports provide the wind conditions to select the correct runway in use, cloud layers, and the local altimeter setting.

Once you have found CTAF frequency and have gathered the weather report from the ASOS/AWOS frequency, you now ready to transmit to your intentions to the pilots in the vicinity of the airport. If you plan on remaining in the pattern, your transmission format will be:

(Airport Name) TRAFFIC, (Callsign/Type), Departing (Runway), (Direction of Traffic Pattern) Closed Traffic, (Airport Name).

An example for Monmouth Executive Airport would be:

Monmouth Traffic, N292SP Cessna 172, Departing Runway 14, Left Closed Traffic, Monmouth.

A valid question is, 'Why would you announce your callsign AND your type of aircraft?' The callsign is important because you are identifying yourself by your registration number, but the type is easier for other pilots to identify. The problem exists when you have multiple aircraft of the same type in the area. Adding your callsign helps everyone to understand who you are and it also important if an accident occurs within the vicinity of the airport.

Every leg of the traffic pattern should be announced. After you depart and you begin your left or right turn, you would say your position... in this case Crosswind. In the case of Monmouth, it would be:

Monmouth Traffic, N292SP Cessna 172, Left Crosswind, 14, Monmouth.

You can substitute the appropriate leg every time into that template. When you are departing the pattern and the airport vicinity, you would announce on frequency:

Monmouth Traffic, 2SP Cessna 172, departing the area to the North, Monmouth.

NOTE: Once you announce your full callsign once or twice, you can shorten it to the last 3 of the callsign.

When turning final in the pattern, it is useful to announce on frequency your intentions. Is this a full stop? Touch and Go? Stop and Go? Low Approach? Something like:

Monmouth Traffic, N292SP Cessna 172, turning Final 14, Touch and Go, Monmouth.

You are not held to this intention in any way if safety becomes a concern, e.g. you botched the landing and need to conduct a full stop instead of a touch and go. That is fine, just exit the runway and advise traffic:

Monmouth Traffic, 2SP Cessna 172, Clear of Runway 14, Monmouth.

This tells other pilots the runway is clear for takeoffs and landings again. Never ever use the phrase 'Clear of the Active.' This is bad phraseology and does not provide any useful information as all runways that are NOT CLOSED are considered 'Active.'

Last but not least we will discuss arrivals inbound to an uncontrolled field. The FAA regulations recommend that you begin your advisory announcements on CTAF no later than 10 miles from the airport. This gives plenty of time for pilots to plan and be aware of another aircraft inbound. You should always enter the traffic pattern at a 45 degree to downwind entry (see first image). If you need to overfly the field and make a teardrop turn that is fine, just do it at least 500' above pattern altitude and then begin your descending teardrop entry into the pattern while still advising traffic. Typically, pilots will monitor frequency before 10 miles out to see if anyone is in the pattern and that way they know what runway is being used and they can enter the pattern correctly. When you are 10 miles out from the airport, you can announce on frequency your locations and intentions, e.g. 'Monmouth Traffic, N292SP Cessna 172, 10 Miles to the South, entering the 45 Left Downwind for Runway 14, Monmouth.' Continue these updates at your discretion. Once established in the pattern, use your standard traffic pattern advisories as discussed earlier.

Understanding how to fly in the traffic pattern may seem like a lot, and eventually mundane once mastered, but it is what will begin your journey to flying under VFR as a safe and proficient pilot.

Another day, you're flying a Cessna 172 VFR in your local practice area without talking to air traffic control when all of the sudden you notice black smoke coming out of the engine. You see an airport in the distance and you head towards it but you have no idea what airport this is. You need assistance from air traffic control, but have no time to figure out the proper frequency to contact, obviously, you are handling an emergency. What do you do?

In both of these scenarios, GUARD frequency (VHF 121.5 and UHF 243.0) can be an effective tool. This is a frequency reserved for emergency transmissions as well as for aircraft that have missed a check in with ATC or not sure what frequency they should be on. 121.5 is used all over the world and nearby air traffic controllers are always monitoring this frequency.

In the first example we described, you could switch to 121.5 and transmit: "Delta 123, on GUARD, I lost contact with Memphis Center, can someone advise which frequency I should be on?" On the reverse side of things, air traffic controllers can use GUARD to locate an aircraft they were expecting to hear from or that have not been responding. For example, an air traffic controller could say: "American 123, Memphis Center, on GUARD, if you hear this message, switch to my frequency on 132.4." Sometimes an aircraft may be unresponsive because they are out of range of an air traffic controller's radio transmitter. Since there are often aircraft positioned in different parts of a center controller's airspace, a controller may ask another pilot for assistance to relay a message on GUARD in the hopes that their location will transmit a better signal to the unresponsive aircraft. In this scenario, GUARD provides an excellent resource in ensuring all aircraft are accounted for.

In the second example, we see the potential use of GUARD in an emergency scenario. The pilot could switch to GUARD and state that they have an emergency and are landing at the nearest airport. Since all air traffic controllers monitor GUARD, a radar controller can transmit on GUARD and provide better assistance to the pilot by issuing radar vectors, recording important information pertaining to the emergency, and coordinate for crash fire and rescue to be ready at the diversion airport. 

Interesting to know as well, when an ELT beacon goes off, it transmits an aural signal on the GUARD frequency. Organizations like the Civil Air Patrol actually practice triangulating and locating a beacon to find the location to prepare for search and rescue missions in the event an aircraft crashes. The beacon signal from ELTs almost sounds like a siren.

One final example worth mentioning is the DOD (e.g. Air Force, Coast Guard) monitor GUARD as well. Aircraft crossing over our international borders without following proper ADIZ entry procedures can be intercepted by military aircraft who will use GUARD frequency in an attempt to establish communication with the violator. If two-way communication is established on GUARD, the intercepting aircraft can provide further instructions to the pilot as necessary.

In conclusion it is strongly recommended, and in most instances required, for pilots to always monitor GUARD 121.5 on their second radio. In fact, airlines require crews to monitor 121.5 on a second radio when the radio is not needed for other operational reasons. Monitoring GUARD provides an extra layer of safety and if you accidentally transmit on GUARD, don't worry, there are plenty of pilots that will key up in a funny voice to remind you "You're on GUARD"... hopefully that doesn't happen during a time when you really need it.

On POSCON, we simulate the GUARD frequency on both VHF and UHF frequencies to provide an ultimate realistic experience. Next time you find yourself on the network in one of these scenarios, try the GUARD frequency. For more information, check out the AIM 6-3-1.

For our example scenarios, we are going to John Wayne - Orange County Airport located in Santa Ana, California (KSNA). This airport has two parallel runways:

Runway 20R/2L - this is the larger of the two runways at 5,701 x 150 feet with all of it available for landing.
Runway 20L/2R - this is the smaller of the two runways at 2,887 x 75 feet with all of it available for landing.

Runways 20L and 20R from X-Plane 11: 

This is an old real world photo when the runways were previously named 19L and 19R.

Not sure if you noticed, but there are two very important differences between the two photos other than the runway naming.

The first difference is that in the X-Plane photo, the runway touchdown zone markings extend the entire length of the runway which gives the flight simulator pilot a false sense of where the touchdown zone is located. In the real world photo, there are only three touchdown zone markings (not including the threshold markings). Each touchdown zone marking indicates 500 feet. You might ask, why are there only three in the real world? For that, lets define the term "touchdown zone".

Touchdown zone = the first 3,000 feet of a runway or first third, whichever is less.

In the case of KSNA, that means the touchdown zone is defined as the first 1,900 feet (5,701 divided by 3). 

So at KSNA, the runway painters only painted 3 markings to indicate the touchdown zone (3 x 500 = 1,500). Anything more than that would give the pilot incorrect information.

The second major difference between the two photos is the fact that the X-Plane runway is simply too long. You can tell this because of the location of the third touchdown zone marking in relation to the taxiway. In the real world photo, the taxiway is located in the same position as the third marking, but in the X-Plane photo, the taxiway is located in the same position as the fourth marking.

These types of scenery inaccuracies present a significant challenge to flight simulator pilots because landing in the touchdown zone is a requirement of every landing and the expected outcome of flying a stabilized approach. If you estimate that you will NOT land in the touchdown zone, a go-around MUST be initiated. POSCON will automatically deduct points from your score if you fail to land within the touchdown zone because it is indicative of an unsafe landing.

We now know what the touchdown zone is and why it is important, but to achieve a safe landing in the touchdown zone, it first starts with a stabilized approach. Significant speed and configuration changes during an approach can complicate aircraft control, increase the difficulty of evaluating an approach as it progresses, and complicate the decision at the decision point (i.e., DA, DDA, DH, MDA). Assess the probable success of an approach before reaching the decision point by determining the requirements for a stabilized approach have been met and maintained. Normal bracketing is defined as small corrections in airspeed, rates of descent, and variations from lateral and vertical path. Normal bracketing is a part of any instrument or visual approach procedure. Frequent or sustained variations are not normal bracketing excursions and are not acceptable. POSCON will automatically deduct points from your score if you fail to conduct a stabilized approach; however, you will only be charged points if the approach results in a landing. If you realize you are unstable and go-around without touching down, no points will be deducted. Let's review the criteria the POSCON grades on:

Stabilized Approach Requirements

On any approach, the following is required:

• Below 2,000 feet above field level, do not descend at a rate greater than 2,000 FPM for more than a few seconds.
• Below 1,000 feet above field level, or inside the FAF, do not descend at a rate greater than 1,000 FPM for more than a few seconds.

EXCEPTION: At special airports such as Lukla (VNLK), Telluride (KTEX), Aspen (KASE), Paro Bhutan (VQPR), etc. OR if you are simulating an emergency, you can "dispute" the point deduction in order to be exempt from the above criteria. We also are considering exempting certain aircraft types as well such as general aviation.

At 1,000 feet above field level:

• You must be in a landing configuration (gear down and final landing flaps), no exceptions.
• On the proper flight path.
• At stabilized thrust (spooled).
• Minimum speed: target speed minus 5 knots.
• Maximum speed: target speed plus 10 knots.

EXCEPTION: In VMC, the requirements at 1,000 feet can be delayed until 500 feet above field elevation, except landing configuration.

These requirements must be maintained throughout the rest of the approach for it to be considered a stabilized approach. If the stabilized approach requirements cannot be satisfied by the minimum stabilized approach heights or maintained throughout the rest of the approach, then you must execute a go-around. The decision to go around is not an indication of poor performance, but rather good judgement.

Main Causes of Unstabilized Approaches

1. Visual approaches.
2. Poor descent and speed planning from cruise.
3. Unreasonable ATC speed or altitude restrictions.

Techniques to Flying a Stabilized Approach

Here are some tips on how to achieve a stabilized approach:

1. Stabilized approaches start with good descent and speed planning.
   • The total flying distance required for a normal descent to landing can be calculated by factoring 3 miles per 1,000 feet or 1 mile per 300 feet (3 to 1 ratio). Sometimes, however, a 3 to 1 ratio cannot be maintained due to high tailwinds, engine anti-ice activation, or ATC assigned speed restrictions. If you are flying jet aircraft, make sure you are not afraid to use speed brakes when necessary as they are a very effective tool to "go down and slow down" simultaneously. If you are in variable pitch prop aircraft, you can push the prop lever full forward which will use the blade of the prop to help slow the aircraft.
   • The best way to slow an aircraft in the descent is to level. It is not always possible, but when it is, it is good practice to build in a few extra miles prior to a speed restriction to level just to make sure you can achieve the desired speed. If the act of leveling gets you off your desired descent path (i.e. too high), you can always add flaps to maintain a high descent rate while maintaining a slow speed. Speed brakes can also help, but avoid using speed brakes below 180 KIAS.
   • Extending your gear is your trump card... play it when necessary. The gear is the biggest drag device you have on your aircraft. If the choice is between going around and dumping the gear early, the gear is always the best option.
2. 1,000 feet is just a minimum. You should target 1,500 feet to ensure you are stable by 1,000 feet. In general, plan to be stabilized on all approaches by 1,000 feet above field level in both IMC and VMC.
3. Use electronic guidance when available. This does NOT mean you need to request to fly the instrument approach, you can simply tune and backup your visual approach using an ILS or RNAV for the vertical guidance that these approaches provide.
   • A good technique on visual approaches is to intercept the vertical path, even if not established on the lateral guidance.
4. If ATC assigns you an altitude or speed restriction you are unable to maintain, then simply say "unable".
5. Know how to properly manipulate the the mode control panel (MCP) or guidance panel (GP) on your aircraft. Knowing what the different modes do will help you make good decisions during the descent phase. Also, it is important to understand how each mode interacts with your auto-throttle system. The last thing you want is the auto-throttles to increase power when you are not ready for them to do so.

Here is an example of what to do when you recognize early that a 3 to 1 ratio descent path is not going to work: 

Okay, now lets say you have tried ALL of the above and you are out of options, what now? Do you have to go-around?

There is one more option... increase the flying distance to the runway. You can do this a number of different ways, but it depends on how far away you are from the runway. 

Early recognition of being unstable: If you realize early that you are going too high and/or fast on approach, you can ask ATC for "vectors for descent". 99% of the time ATC will be happy to accommodate this request because they rather give you a chance to make a stabilized approach than have to deal with your go-around. 

Late recognition of being unstable: If you realize that you are going to be high and/or fast and you are on final approach, then things become a little bit more complicated. With the exception of the C172-type aircraft and their ability to forward slip, the only option is an S-turn... yeah, that thing from the private pilot training. If you are flying into a controlled airfield, you need to request to conduct this maneuver from ATC. If you are flying into an uncontrolled field, you can simply perform this maneuver on your own.

CAUTION: Some people may suggest a 360 degree turn for stabilization on final as it is common practice at uncontrolled fields. I personally do not recommend this maneuver as it can lead to bad things if aircraft are behind you. If you feel that the S-turn technique will not work, it is better to just level at pattern altitude, fly upwind and then re-enter the traffic pattern.

The S-Turn Technique

The shortest distance between two points is a straight line, thus if you want to increase the distance to a runway (i.e. the time to descend and slow), you need to add a bend in your flight path. In order to do this, first make sure you are above 1,000 feet above field level and in VMC. If not, you need to go around and try the approach again. If you are, I recommend the following technique:

1. Turn 30-45 degrees off course.
2. Maintain throttles to idle.
   • If you are too high: pitch for maximum vertical descent rate based on height above field level (e.g. do not exceed 2,000 FPM below 2,000 feet AFL or 1,000 FPM below 1,000 AFL).
   • If you are too fast: pitch for desired airspeed.
3. Evaluate your glide path using visual or electronic means.
4. When you feel comfortable with the stability of your approach, turn back towards the airfield and intercept the straight-in final.
   • CAUTION: Do not let the maneuver deviate more than 1 mile from the straight-in lateral track, otherwise you might as well go around and re-enter the pattern.