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I'm currently studying for an IR (US). One of the exam practice questions concerns an IAP having only circling minimums, and references 5-4-20(c) of the AIM, which reads:

Straight-in Minimums are shown on the IAP when the final approach course is within 30 degrees of the runway alignment (15 degrees for GPS IAPs) and a normal descent can be made from the IFR altitude shown on the IAP to the runway surface. When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies. The fact that a straight-in minimum is not published does not preclude pilots from landing straight-in if they have the active runway in sight and have sufficient time to make a normal approach for landing. Under such conditions and when ATC has cleared them for landing on that runway, pilots are not expected to circle even though only circling minimums are published. If they desire to circle, they should advise ATC.

I'm having trouble understanding the bolded sentence What does it mean to land straight-in from an approach that is more than 30 degrees from runway alignment? I've been understanding a circling approach as something like a pattern landing where you start the maneuver once you have passed the FAF and have - and can keep - the runway environment in sight. But this seems to imply something different. What am I missing? What does "a normal approach to landing" mean here?

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The sentence before the one you bolded, with my bolding applied, says:

When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies.

So you can have a "circling approach" that is lined up straight in to a runway, but with only circling mins, not straight-in minimums, published. This could be driven by the need for a high FAF altitude, high enough that you can't get from that FAF at that altitude down to the runway, with a descent rate that's within the TERPS criteria. So they build an approach that assumes you maneuver to lose the excess altitude, and give you circling mins so that you can.

However -- and this is what the exception that you bolded in the question is about -- if you're in, let's say a STOL airplane, you may very well be able to lose the excess altitude and be established on a normal visual glidepath to the runway with ample time to make a "normal approach and landing" without any S-turns or other maneuvering required. And in that case you're absolutely allowed to fly the approach straight in. The guy behind you in a Lear Jet may not be able to do the same thing that you did, and the TERPS descent profiles criteria are written to guarantee that if he has straight-in mins, he CAN get from the FAF at its crossing altitude to the runway without having to use what would be, for him, a dangerously high descent rate (angle). But in the STOL aircraft, a steep descent is perfectly normal, so you can go ahead. The Lear shouldn't try to mimic the Maule's descent profile, but that doesn't mean that the Maule has to mimic the Lear's descent profile.

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  • $\begingroup$ Is this really just about STOL? That seems unusual. There's two cases (plus any combination) that seem to apply. One is a >30 deg heading change from approach to runway. The other is a steep descent. I can see how in a 172 you could do a 1000'/min descent to land no problem. But in the >30 deg case, what does "straight in" actually mean here? Or does it just not apply in that case? $\endgroup$ – Foster Boondoggle Mar 28 at 4:34
  • $\begingroup$ It isn't about STOL, but rather 91 vs 135/121 operators. The latter are required to have a stabilized approach by a certain altitude or go missed, whereas the former are limited only by the "careless or reckless" rule and thus have a lot more freedom in how they comply with intentionally vague rules like this. $\endgroup$ – StephenS Apr 5 at 1:47
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If you break out of the clouds with sufficient altitude, you can line up with your desired runway of use before reaching the MAP. You can only do this if you can effect the landing using normal maneuvering procedures. Breaking out of the clouds before the FAF with 10sm or more visibility would be a perfect scenario to deviate from the lateral guidance and line up for the straight-in landing.

You can also request a Contact Approach per AIM 5-4-25.

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  • $\begingroup$ Aside from the contact approach option, which rumor has it no one ever actually asks for, would you have to request a visual approach instead or cancel IFR? My understanding has been that you're not supposed to deviate from the approach course until the MAP. $\endgroup$ – Foster Boondoggle Mar 28 at 21:34
  • $\begingroup$ @FosterBoondoggle - Once you are on the approach, you are communicating directly with the tower. You could request anything you want. They are there to help you. Just make sure you stipulate that you are in VMC. That way they do not mistake your intentions for flying a Charted Visual Flight Procedure. See faa.gov/other_visit/aviation_industry/airline_operators/… $\endgroup$ – Dean F. Mar 29 at 0:38
  • $\begingroup$ @FosterBoondoggle - According to the Aeronautical Information Manual (AIM), a Visual Approach authorizes a pilot flying under Instrument Flight Rules (IFR) to proceed visually to the airport while remaining “clear of clouds.” Clearance for the approach is predicated upon the pilot having either the airport or the preceding identified aircraft in sight and the airport reporting a ceiling at or above 1,000 feet and a visibility of 3 miles or greater. $\endgroup$ – Dean F. Mar 29 at 0:39
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    $\begingroup$ @FosterBoondoggle - Is it a separate clearance? In some cases, yes. And, in others, no. We have an IAP at my local airport that has the MAP right at the beginning of the downwind leg of RWY36. This IAP has only circling minima. Albeit, 230 feet lower than the traffic pattern altitude. If I break out of the clouds before reaching TPA, I am not going any lower than TPA until I am abeam my touchdown point. This will not require another clearance besides clear to land if it has not already been given. $\endgroup$ – Dean F. Mar 29 at 1:12
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    $\begingroup$ @FosterBoondoggle - if on the other hand, I am cleared to land on RWY18, I could effectively side step to the right (RWY 36 is RP) as long as I break out of the clouds at least 2 miles before the MAP. My instructor would do it in less than 1 mile. Then again, it’s a 7000 foot runway in a C172. Just as long as I remain above the decision height until I can stay out of any clouds and retain suitable visibility. Typically, if the clearance is for 36, ATC will give the instruction to circle East of the field. If for 18, they will instruct to keep the circle North of the field. No further clearance $\endgroup$ – Dean F. Mar 29 at 1:45

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