Circle to Land Explained | How to Go Missed on a Circling Approach

instrument approaches are designed to line you up to land on a runway but what happens when the runway you want to land on doesn't have an approach guiding you straight into it the airport at millville new jersey has four runways but unless your aircraft is equipped for r nav approaches your only choice is the ils or localizer approach to runway 10. but let's say there's a very strong wind blowing right down the center line for runway 3-2 we can still use this approach for runway 1-0 to land on 3-2 using what's called a circle to land but there's no such thing as a circling approach per se a circle to land always starts with an approach with some other form of guidance here it could be the ils or the localizer but the minimums allowed for a circle to land are different and typically higher than those for a traditional approach here we see that for a category a aircraft like a cessna 172 or piper cherokee our circling mda is 520 feet when we can identify the zekre fix whereas the localizer mda is 440. so why is the circling minimum higher the straight-in approach only has to provide obstacle clearance for a small area along the extended center line of the runway whereas the circling approach has to protect the area around the whole airport here's how it works the circling radii are based on the category of aircraft flown we'll start with a category a aircraft the protected area is created by moving 1.3 nautical miles out from each runway end and drawing an arc along this radius here are the arcs for runway 1 0 and 2 8 we'll also do the same thing for runway 3 2 and 1 4. these four arcs are joined by what the aim calls their tangential connections to complete the circling protected area an aircraft at or above the mda here 520 feet will have at least 300 feet of obstacle clearance within this area as you can see this provides adequate clearance above that 218 foot obstruction it's a water tower just south of the field let's have a look at the minimums and protection for a category d aircraft one whose approach speed exceeds 140 knots here the minimum is higher you're restricted to going no lower than 660 feet but the protected area is larger a radius of 2.3 miles this allows for more maneuvering for these faster and typically larger aircraft to put that in perspective here's a top-down view of the field the category a protected area covers this area while the expanded area for cat d aircraft encompasses all of this in order to protect this larger area the minimum altitude has to be higher so we're circling from runway 1-0 to runway 3-2 here we should do that by as soon as we get visual sight of the runway maneuvering the shortest path to the base or downwind leg there's no hard and fast rule on how to do this we're at an uncontrolled airport here in millville so it's advisable to join the traffic pattern that the faa calls for if this were a towered field we might coordinate which direction we would circle with the tower we could even overfly the field of conditions warranted here we're going to enter a left downwind and base for 3-2 so when our cad a aircraft will approach at the circling mda of 520 feet gain sight of the runway break off to the right and enter downwind and base for 3-2 we'll stay at the circling minimum altitude until we're in a position to make a normal descent to land on runway 3 2. remember that at 520 feet we're significantly below a standard traffic pattern altitude so we can execute this circle to land with a more or less normal downwind and bass leg from the top down view we see that this track kept us inside our protected area for cad aircraft but not by much it's a somewhat tight pattern now a lot can go wrong on these circling approaches first of all we're at a very low altitude maneuvering at low air speeds in a somewhat dirty configuration like with flaps and gear extended secondly this is a visual approach once we break off from the localizer we're not following any guidance except what our eyeballs provide if we lose visual reference of the runway at any time we should execute a missed approach it's easy to initially gain sight of the runway and final and then lose sight of it while maneuvering for the circle but how do we execute a missed approach here the missed approach is to make a climbing turn out to the northeast direct to the cedar lake vor but the missed approach point is at the approach end of the runway what happens if we've broken off from the localizer and are downwind for 3-2 and lost side of the runway we'll decide to go mist at that point but we're way past the missed approach point the easiest way to go direct from here to the cedar lake vor is to make a slight left turn and just climb out but what kind of obstacle protection do we have we know we're protected inside the gold area at or above 520 feet but what happens when we leave that area we don't have any obstacle protection guarantees out there since we're not on any published missed approach route the best course of action then is to start a climbing turn in towards the runway we'll gain enough altitude to go direct to cedar lake and then proceed on from the side we can see our altitude gain taking place in this circling turn which keeps us within the safety of the protected area for the circle of the land before proceeding to cedar lake at two thousand feet now on this approach we might be okay in terms of obstacle clearance these are the floodplains of the delaware river after all pretty flat around here in southern new jersey but where it really matters is these approaches in mountainous areas here's the ils and gunnison colorado the circling procedure involves flying in on the localizer initially leveling out at the circling mda of 90 260 feet and entering a downwind for the opposite runway now let's say it's at this point we lose sight of the runway and need to go mist we're inside the protected area for the circling maneuver but we can only stay at this lower 9260 feet for as long as we're inside that area the missed approach is a somewhat involved and very specific procedure we start with a climbing right turn to a 180 heading intercept the zero five zero radial off the blue mesa vor and fly that inbound also notice the altitudes for the procedure are ten thousand and twelve thousand feet significantly higher than our circling mda so starting the procedure late like we are will need to turn in toward the runway and climb to a safe altitude before proceeding on the mist circling to land involves maneuvering at dangerously low altitudes and poor visibility so for years the industry was lobbying the faa to expand protected areas for circling in 2012 they created expanded circling approach airspace radii and began applying these expanded requirements to existing approaches you could see if the approach you're flying has these expanded protections if next to the circling minimum section you see a c in a black square or what's called a negative c let's compare the expanded circling protections by first revisiting the standard circling protections here are the radii for four categories of aircraft note that these distances are fixed regardless of what altitude the circling mda is here are the expanded radii first notice that a distinction is made on what the circling mda is for a given approach and the distances are significantly longer especially when you consider those for the faster cat c d aircraft also notice that the higher the circling mda altitude is the larger the protection area can you think of why aircraft at higher altitudes would need larger protections remember that aircraft categories are based on approach speeds and those speeds are in not indicated airspeed as aircraft get higher and air density decreases the same indicated airspeed will have a higher true air speed cat d aircraft will fly an approach with 145 knots indicated at sea level its true airspeed will be close to that 145 knots but at higher altitudes that true air speed will be higher this aircraft will need more room to maneuver not all approaches have this expanded circling protection so look for that negative c symbol on the minimum section so far we've looked at approaches which allow for straight in landings to a particular runway but which we've decided to do a circle the land sometimes we don't have that option we must do a circle to land here's two approaches where that's the case one at clearview in maryland and another and telluride colorado first notice the titling a straight in approach will have the runway number in its title such as the ils one zero but a circling only approach will replace that number with a letter starting with a and then moving through the alphabet for other approaches at the same airport so we have the vr alpha clear view and the vor dme alpha at telluride one reason why circling only minimums are given for an approach are shown here at clearview the approach course is 235 degrees but neither runway 1 4 or 3 2 is aligned with the approach course if the final approach course alignment with the runway center line exceeds 30 degrees like it does here the approach is circling only another reason is seen here at telluride look at that steep angle of descent going from map c to the runway threshold involves a descent rate of over 650 feet per nautical mile a cat d aircraft approaching at 140 knots would need a descent rate of 1800 feet per minute to make a straight in landing to runway nine air there's just no way for that aircraft to make a stable approach to land with that kind of scent rate so it'll enter a circling pattern to lose altitude more gradually so if an approach involves a descent of more than 400 feet per nautical mile to the threshold crossing height it'll be certified as circling only just because an approach is circling only however doesn't mean you can't perform a straight in landing if your approach speed allows for a stable descent to the runway many circling only approaches can be flown as straight in by a cat a aircraft just fine circling approaches are one of the most challenging maneuvers in instrument flying even with the protections afforded there's restrictions on when and how you can fly them this approach atelier ride restricts circling to the north of the airfield due to terrain and like many approaches restrict circling at night before attempting a circle to land make sure you're very familiar with the aircraft's performance the exact circling procedure to be flown and your own level of comfort performing circling approaches airlines recognize the risk of circling approaches and won't even bother having their pilots demonstrate circle to lands on their type rating check rides for this reason you'll often see restrictions on atp certificates circling approach vmc only can all take a page from the airline's book and only perform circling approaches as a last resort if this was helpful please click subscribe so that 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Channel: FlightInsight

Views: 84,368

Keywords: circle to land, circling approach, circle to land approach, circle to land approach explained, circle to land procedure, circle to land missed approach, missed approach, circling approach explained

Id: 8ZlUgv84m80

Length: 11min 35sec (695 seconds)

Published: Tue Sep 14 2021