Precision approach now breaking out

[Captain]

Ron:

I guess we're saying basically the same thing then. The only point we differ is the nano second AT the DA (which is actually an infinantly small point in time). I fly a crew where the PM is reading the altitude above...'1,000 above...500 above...200 above...100 above...minimums'. So I have a guy who is just outside and maybe that makes the difference. I don't think so. I'm thinking if I were by myself I'd be able to sneak a peek enough on the way down and then finally look up AT da and decide. If that puts me 3.6 micro seconds in violation of the FARs then I'm okay with that. I look, I decide, and I never take my time deciding. It's the DA and I either have it or not and act accordingly.

I learned in the 310 that putting out too much drag on one engine on an ILS can seriously bite you in the ass. I was lucky enough to do all the multi training in an area with terrain and real imc.

I'd guess most planes have restrictions on flaps when landing SE. Maybe even 'full flaps when landing is assured' or something like that when SE.

I guess we'll have to agree to disagree. IME, I've found the transition from half to full flaps precipitate an undesirable temporary deviation from the GP no matter how hard I try to anticipate/avoid it. And when the visibility is on the low end of acceptable I feel much better about the rather minor risks associated with a half flap landing than the risks of chasing the glidepath close to the ground while fighting with visual illusions and mis-perceptions. In any case a partial flap landing isn't all that unfamiliar to me because I practice them on occasion.

That's fine assuming performance isn't an issue. Granted if you're flying an ILS in a light twin or other small GA plane it's most likely not an issue. It is often an issue for me. I'm thinking F45 or KMYF are places where I really need full flaps on an ILS to get down and get stopped.

 

[Greg Bockelman]

As I read that, if you don't already have one of those visual references in sight upon reaching DH, you may not continue the approach below DH and must "initiate an immediate missed approach," i.e., ou are not permitted to continue below DH while you look. Yes, you may sink/settle below DH as you are starting the missed, but you've already made your decision to go missed no later than reaching DH.

IMO, continue is the key word. It only takes a second to look. You see "environment" you continue. You don't, you go missed.

It is my opinion that you will have a pretty good idea whether to miss or continue as you reach DH.

 

[poadeleted20]

IMO, continue is the key word. It only takes a second to look. You see "environment" you continue. You don't, you go missed.

It is my opinion that you will have a pretty good idea whether to miss or continue as you reach DH.

Maybe it's just semantics, but even if it only takes a second, if you see the altimeter hit DA and then look outside for those visual references, you'll be ten feet below DH before you make the decision, and that's a technical violation of 91.175.

 

[alfadog]

Maybe it's just semantics, but even if it only takes a second, if you see the altimeter hit DA and then look outside for those visual references, you'll be ten feet below DH before you make the decision, and that's a technical violation of 91.175.

This line of discussion seems kind of weird to me. I have been training with my Francis Hood and have no ideal of what it looks like outside. But in real life you are doing a scan, why in the world would your scan not include the windshield? Are people arguing that they are they are so involved in their needles that they have no idea what is going on outside? Really? Or am I missing the point?

 

[poadeleted20]

This line of discussion seems kind of weird to me. I have been training with my Francis Hood and have no ideal of what it looks like outside. But in real life you are doing a scan, why in the world would your scan not include the windshield? Are people arguing that they are they are so involved in their needles that they have no idea what is going on outside? Really? Or am I missing the point?

I think you have hit on the point exactly. DH is not the time to start looking. When you reach DH, you should already have been looking out, and if you haven't seen anything by then, away you go.

 

[Jaybird180]

As a n00b, I couldn't wrap my mind around the differences between DH, DA and MDA. The reference you cited didn't make the task any easier when it seems the FAA and your IPC requirements makes them functionally the same.

 

[RotorAndWing]

Maybe it's just semantics, but even if it only takes a second, if you see the altimeter hit DA and then look outside for those visual references, you'll be ten feet below DH before you make the decision, and that's a technical violation of 91.175.

 

[poadeleted20]

DH is the height above the touchdown zone on a precision approach at which you initiate your missed approach if you do not meet the criteria to continue down. DA is what you see on your altimeter when you reach DH.. MDA is the altimeter altitude below which you are not allowed to go on a nonprecision approach until you meet the three criteria in 91.175.

 

[Captain]

I'm not sure what you're suggesting but I'm pretty sure your DPE didn't recommend continuing an approach beyond DA regardless of the weather unless you truly were so low on fuel that a diversion to somewhere with better weather wasn't feasible (in which case you already made some significant mistakes). Also, from simulated IC practice I can say that flying an ILS to the runway in 0/0 conditions isn't for the faint of heart and it's not something I'd recommend trying for real if you've never practiced it before (I'll grant that there's an advantage to crashing on an airfield vs into someones house though). A trick I learned is to use the autopilot in pitch hold mode (rather than coupled) during the descent prior and beyond DA coupled with a commanded pitch up to +5 to 6 degrees when your altimeter (or better yet your WAAS GPS) indicates you're about 20 ft in the air. If you fly the approach coupled all the way to the runway there's a good chance the autopilot will generate significant pitch excursions close to the ground and flying fully coupled to DA and then hand flying is likely to induce unwanted pitch changes as well when you disconnect.

No way would I practice landing a real airplane 0/0. I did, however have some extra sim time so we shot a 0/0 approach. There's a confidence builder! Nice to have that in the tool belt.

 

[Jaybird180]

DH is the height above the touchdown zone on a precision approach at which you initiate your missed approach if you do not meet the criteria to continue down. DA is what you see on your altimeter when you reach DH.. MDA is the altimeter altitude below which you are not allowed to go on a nonprecision approach until you meet the three criteria in 91.175.

To summarize your interpretation of the regs:
DH is associated with precision approaches
DA is the altimeter reading

MDA is associated with non-precision approaches

Neither of which you may decend below during any kind of approach if any 1 of 10 criteria are not met.

Is that correct?

-versus-

A DH is just that, the height where you make a decision. There is no reason to be already executing a missed approach at that point. Get to the DH, look outside and decide. If you see lights then continue to 100 HAT, if you see a runway then land. If not then go missed. If your personal minimums are such that you want to decide before the missed then fine. Add what you want and make that the DH. Procedure is still the same, make a decision AT the decision height.

My interpretation of Captain below:

Get to DH, see 1 of 10 criteria > decend > see runway > land
-or-
Get to DH, do not see 1 of 10 criteria > go missed
-or-
Get to DH, see 1 of 10 criteria > decend > do not see runway > go missed

Does that muddy the water any?

 

[John Collins]

To summarize your interpretation of the regs:
DH is associated with precision approaches
DA is the altimeter reading

MDA is associated with non-precision approaches

Neither of which you may decend below during any kind of approach if any 1 of 10 criteria are not met.

Is that correct?

-versus-



My interpretation of Captain below:


Does that muddy the water any?

You are close. Captain was referring to the caveat that if you have the approach lights in sight, you can continue below the DA or MDA until 100 feet above the threshold without actually seeing the runway. At 100 feet you have to see one or more of the runway cues or the red terminating bars of the approach light system to continue to the runway. The reason for this exception has to do with how far you can see if the conditions are at the specified minimums say 1/2 mile, in other words, you can see the approach lights and still be too far from the runway to see it. The approach lights allow you to continue the descent until you are within the distance that is equivalent to the minimum visibility requirement and should be able to see the runway. If the approach doesn't have approach lights or the lights are not working, the visibility requirement is raised.

 

[Greg Bockelman]

you'll be ten feet below DH before you make the decision, and that's a technical violation of 91.175.

I guess that is a matter of opinion, because I don't believe that it is. Depends on how you interpret the word "continue". If I look up at DH and see nothing, I execute a missed approach. If I descend a tad below DH, I am not CONTINUING, I am in the process of executing the missed approach. And I do not believe that is a violation.

 

[Everskyward]

To summarize your interpretation of the regs:
DH is associated with precision approaches
DA is the altimeter reading

MDA is associated with non-precision approaches

Neither of which you may decend below during any kind of approach if any 1 of 10 criteria are not met.

Is that correct?

May this will help.

http://www.skybrary.aero/index.php/Decision_Altitude/Height

The Decision Altitude (DA) or Decision Height (DH) is a specified altitude or height in the Precision Approach or approach with vertical guidance at which a Missed Approach must be initiated if the required visual reference to continue the approach has not been established. (ICAO Annex 6)

Decision altitude (DA) is referenced to mean sea level and decision height (DH) is referenced to the threshold elevation.

The DH for Category II and III approaches is invariably assessed by reference to a radio altimeter and never a barometric altimeter; therefore the minima can only be expressed as DH and not DA. For approaches with DH of 200ft or higher, radio altimeter reading would be unreliable due to the unevennss of the terrain; therfore a barometric altimeter is always used and the minima may be expressed as DH or DA.

So DA is MSL and DH is AGL above the threshold. Unless you have a radio altimeter in your airplane you have no way of measuring AGL. Besides which, as noted in the explanation, the terrain elevation can vary when you are not right above the threshold so that it would not be accurate for this purpose.

I have always heard the same interpretation as Greg and Captain, that if you decide to miss at DA you can sink somewhat below it as you execute the missed approach. Really the decision is if you can see one of the required items or not. You should have already decided to miss if you can't.

 

[matthammer]

I have always heard the same interpretation as Greg and Captain, that if you decide to miss at DA you can sink somewhat below it as you execute the missed approach. Really the decision is if you can see one of the required items or not. You should have already decided to miss if you can't.

Same here. I think that position is also substantiated by a note in the ATP PTS on page 2-27:

Descending below the MDA or continuing a precision approach
below DH/DA as appropriate, unless the runway environment is in
sight is considered unsatisfactory performance. However, even if the
missed approach is properly initiated at DA/DH, most airplanes
descend below DA/DH because of the momentum of the airplane
transitioning from a stabilized approach to a missed approach. This
descent below DA/DH is not considered unsatisfactory, as long as
the precision approach was not continued below DA/DH. (emphasis added)

I think the appropriate definition of a "continued approach" is a continued descent with intent to land. Sinking below DA/DH after or while initiating a missed simply isn't a continued approach.

 

[matthammer]

I think the most important thing about breaking out on a precision approach is nothing.



Yes, nothing.

You're already on a stablized path to the runway in both the vertical and horizontal planes, and if you do nothing, you'll hit the runway right in the touchdown zone blocks. So, be very wary of doing anything much in the way of pitch/power changes until you reach the runway threshold when you ease the power for the flare. If as you hit DH you leave the power where it is and just extend the last flaps while holding pitch attitude steady (i.e., don't let the nose rise or fall with the flaps change), you'll probably find it puts you right where you want to be in terms of speed, height, and attitude to start the flare and land in the proper touchdown zone.

I don't disagree. Although I've flown light GA aircraft that were in need of a rigging adjustment, and I'm fairly certain that if you did absolutely nothing you wouldn't hit runway. My point was simply that you should, situation permitting, use all available resources. If you're flying VFR at night and landing on an ILS equipped runway, I'd still recommend you put the ILS freq in and put the GS needle in your scan. I think that advice is all the more valid after breaking out of the clouds at night in low visibility. It's just one more piece of information to keep you out of the approach lights.

 

[DouglasBader]

While there's a lot to be said for the stabilized approach, consideration needs to be given to the type of operation and aircraft. It's well and good to configure a Boeing before the FAF, but some aircraft like the Twin Commander 500 do best having the final flaps configured only after the runway is fully made. Lots of area, lots of drag. In most aircraft I don't practice or preach configuration upon breaking out, but there may be exceptions, and one does well to keep that in mind. That said, in most aircraft for an approach in actual conditions, one is still better off carrying extra power as needed and flying the procedure configured. Not always, but usually.

As for the transition upon reaching DA/DH, if your needles are crossed, keep them crossed and continue. Under perfectly calm conditions, if you're trimmed and configured and stable on the approach, then you simply continue with the same rate of descent and configuration and airspeed, and you'll land where you're supposed to land. This isn't the case when it's really gusty, on a hot desert day, and other conditions that mean one is working for it all the way to a landing.

It's common, even on an autopilot-managed approach, for people to change their approach path upon going visual at DA/DH. I see retrimming often take place as soon as the autopilot is disengaged, and it's common when a hand-flown approach takes place to deviate from the glideslope upon breaking out. Sometimes people tend to try to dive below the glidesope as they aim for the numbers, and more commonly people tend to let the glideslope fall beneath them. Overcoming the tendency to reinvent the wheel and to begin making trim and power changes at the last minute helps a lot in overcoming these tendencies, but one should still concentrate on flying the glideslope to the runway.

The VASI or PAPI often isn't coincident with the electronic glideslope. If you're on the glidepath on the ILS, there's no need to try to catch the VASI or PAPI. Use it as a reference, but don't lose the reference from the electronic glideslope.

While I fly light aircraft for profit and fun, my day job is a heavy airplane, and involves a lot of IFR. I once sat right seat for a captain who flew a coupled approach down to category 1 minimums, in a picture-perfect approach that gave no hint of trouble. The runway was short, with a reasonably stiff quartering headwind, and some snow drifting across the runway. Later when asked, that individual told me that upon reaching DA with the runway in site, he abandoned the glideslope and preferred to use a visual aiming point. The company taught differently; we train to keep the glideslope all the way to a touchdown, where practical.

In this particular case, at DA, the captain snicked off the autopilot, and at about 100', the glideslope fell away beneath us. He floated, ended up landing long, and found the runway braking action wasn't nearly as good as anticipated. He carried full reverse to a stop that ran so long we had to look out the side windows to see the end of the runway when we came to rest. A big orange ball of flame erupted forward from our No. 2 engine thanks to the mother of compressor stalls, and we shut it down.

Later, when I asked him what he was thinking, he told me that he didn't trust the glideslope after DA, and that he always used a visual aiming point. That thinking was nearly disasterous. You can get away with a lot more in a light airplane, but the concept remains the same. If you have good guidance that's available, and you've been flying it all the way down the approach, it's there for you to continue to the runway. That doesn't mean stay heads-down and don't look up, but there's a lot to be said for the half-in, half-out concept of keeping the glideslope in your scan as you continue past the MAP/DA to the runway.

 

[Jaybird180]

The VASI or PAPI often isn't coincident with the electronic glideslope. If you're on the glidepath on the ILS, there's no need to try to catch the VASI or PAPI. Use it as a reference, but don't lose the reference from the electronic glideslope.

interesting...

 

[Captain]

I simply love it when a guy flys an ILS in the soup, breaks out and turns off the AP and for some reason thinks he needs to make some big adjustment. Usually it's because we were in a crab due to crosswind. Now that he's flying I guess crab isn't needed for some reason... and then it's a freaking mystery why the runway is drifting away to the left or right.

Seriously, I've seen it in A320's. Why would someone turn of an AP on an ILS at 300 or 400 feet and think a 20 degree turn is in order? If the AP needed 20 degrees of crab why on gods green earth wouldn't you?!?

rant off...sorry.

 

[Bob Noel]

While there's a lot to be said for the stabilized approach, consideration needs to be given to the type of operation and aircraft. It's well and good to configure a Boeing before the FAF, but some aircraft like the Twin Commander 500 do best having the final flaps configured only after the runway is fully made. Lots of area, lots of drag. In most aircraft I don't practice or preach configuration upon breaking out, but there may be exceptions, and one does well to keep that in mind. That said, in most aircraft for an approach in actual conditions, one is still better off carrying extra power as needed and flying the procedure configured. Not always, but usually.
...

Doesn't it really come down (no pun) to knowing your airplane and training/practicing how you fly it on the ILS?

 

[Captain]

Doesn't it really come down (no pun) to knowing your airplane and training/practicing how you fly it on the ILS?

No. My way is the best and everyone should do it just like me.



that was in jest for those who weren't sure...

 

[Jaybird180]

No. My way is the best and everyone should do it just like me.

Ain't buying it

 

[DouglasBader]

Doesn't it really come down (no pun) to knowing your airplane and training/practicing how you fly it on the ILS?

Yes, and no. I think it does, to a degree; after all, one shouldn't necessarily fly a Lancair the way one flies a 182.

The stable approach concept is a good one, and a well-proven practice for general IFR operations (and VFR, as a rule), but there are always exceptions. The mountain airport requiring a continuous turn to final is an example. When we train for a two-engine approach (we start with four, as a rule), we don't get fully configured in preparation for the landing, and we don't drop the gear until we're landing assured, and we don't configure the final flaps until shortly before touchdown.

In a large airplane, we don't suck up the flaps on the runway, but I do it all the time in light airplanes to dump lift. In a light airplane we hold the nose off the runway and take advantage of aerodynamic braking. In many swept-wing turbojets, lowering the nose to the runway dumps lift, and coupled with spoilers, allows the brakes to do their job.

That said it's easiest to get a good landing out of a good approach, and a screwed-up approach has a greater liklihood of resulting in a screwed-up landing, or the inability to make a good landing.

Many companies have a policy of being stabilized by 1000' on the procedure when IMC, and 500' when VMC. That's not a bad policy. Our company policy is that by 1000' we must be stabilized, configured, not more than Vref +20 knots, within a dot of the glideslope, sink rate not greater than 1000 fpm, all briefings and checklists complete, no unusual power requirements, flight deck within the lateral confines of the runway at 100' (not as intuitive as it sounds with a 231' long airplane in a strong crosswind), etc. Does this mean that such criteria apply in a Cessna 210? No. Nor do they apply necessarily in a Cessna 310.

In a Part 25 airplane, one can go around with a failed engine. No such capability is required of a Part 23 twin; even a King Air 90 can't do it with a full load on a hot day at a high density altitude airport, and one shouldn't try. The mentality, planning, and actions in the light airplane differ somewhat from the way it's done in a heavy, big one, in some cases. It stands to reason, then, that no one-way-fits-all form exists.

I find it particularly annoying to be lectured in some of the popular flying rags by airline pilots who insist that their way is the only way, any more than anyone with a limited view of aviation should lay down the law for anyone else.

 

[aterpster]

I guess that is a matter of opinion, because I don't believe that it is. Depends on how you interpret the word "continue". If I look up at DH and see nothing, I execute a missed approach. If I descend a tad below DH, I am not CONTINUING, I am in the process of executing the missed approach. And I do not believe that is a violation.

I hear you and agree. But, the FAA has held many times that the decision must be complete at DA then the acceptable height loss at that point is because of the GA.

 

[Captain]

If AT the DA you look up and decide then you are compliant. If you look up and him and haw whilst you decide then you are not.

Ron mentioned 10 feet. I think the FAA would be be fine with 10 feet in the scheme of things. It takes time for my neurons to fire and 'decide'. I'm not playing a game here. I'm serious in that AT the DA I look out and decide right there if I can see it or not. If I decide I cannot then I go missed...even if during the missed I see approach lights.

The point is the decision happes at a point...the DA. Btw, there is a rhythm to it...300...200...100...DA. The human mind can recognize that rhythm and be looking at the right time.

 

[olasek]

My interpretation of Captain below:

Frankly I don't like Captain prescription: get to DH, see, decide ...
Human brain, decision making, works much slower. If you were to follow this line of action you would be say at DH minus 20 before you decided to go missed. I think Ron's explanation of what should/is happening is in my opinion much closer to reality - you are in fact constantly processing information what you see seconds before you reach your DA so when you reach DA you already had made your decision.

 

[Greg Bockelman]

But, the FAA has held many times that the decision must be complete at DA...

Got a reference for that?

 

[Captain]

Frankly I don't like Captain prescription: get to DH, see, decide ...
Human brain, decision making, works much slower. If you were to follow this line of action you would be say at DH minus 20 before you decided to go missed. I think Ron's explanation of what should/is happening is in my opinion much closer to reality - you are in fact constantly processing information what you see seconds before you reach your DA so when you reach DA you already had made your decision.

The human brain takes what it takes to process. The FAA doesn't apply a synaptic gap factor to the DA. They factor in whatever time it takes neurons to fire. A normal brain is assumed and confirmed by the Class 3 medical. (not perfect...but something anyway).

Point is, looking for the runway AT the decision altitude satisfies the regs. That is a fact. See what you see and decide. See nothing then go missed. See lights then continue. See the runway then land. It's really pretty simple.

 

[DouglasBader]

The Captain is correct.

I have always heard the same interpretation as Greg and Captain, that if you decide to miss at DA you can sink somewhat below it as you execute the missed approach.

"Somewhat below" is a little nebulous. Decision height is just that because it's the decision point. It is NOT a hard deck.

It's not uncommon in a transport category aircraft to touch the runway during a go around/missed approach, especially with a cat II approach.

On a precision approach, the procedure is continued to DA/DH. It's at that point in time when the go around is initiated if the required references aren't in sight. It's expected that the aircraft will continue to sink below the decision altitude during this process.

When I execute a missed approach, the procedure is to announce the go-around, call for go-around thrust, and make an initial pitch for 9 degrees. Why not ten? Because beyond that, a tail strike can occur.

I'll definitely be below decision altitude at that point.

 

[Palmpilot]

I'll definitely be below decision altitude at that point.

The laws of physics guarantee that!

 

[aterpster]

Got a reference for that?

Nothing comprehensive. I am out of town with only my laptop until late next week. By "held" I didn't mean to imply an enforcement proceding, rather all-weather flying meetings and discussions. I'll look further when I return home.

There is the PG/C definition, which is ICAO-speak, but there has been harmonization in this area:

DECISION ALTITUDE/DECISION HEIGHT
[ICAO]− A specified altitude or height (A/H) in the
precision approach at which a missed approach must
be initiated if the required visual reference to
continue the approach has not been established.

Note 1: Decision altitude [DA] is referenced to
mean sea level [MSL] and decision height [DH] is
referenced to the threshold elevation.

Note 2: The required visual reference means that
section of the visual aids or of the approach area
which should have been in view for sufficient time
for the pilot to have made an assessment of the
aircraft position and rate of change of position, in
relation to the desired flight path.

 

[aterpster]

The Captain is correct.



"Somewhat below" is a little nebulous. Decision height is just that because it's the decision point. It is NOT a hard deck.

It's not uncommon in a transport category aircraft to touch the runway during a go around/missed approach, especially with a cat II approach.

On a precision approach, the procedure is continued to DA/DH. It's at that point in time when the go around is initiated if the required references aren't in sight. It's expected that the aircraft will continue to sink below the decision altitude during this process.

When I execute a missed approach, the procedure is to announce the go-around, call for go-around thrust, and make an initial pitch for 9 degrees. Why not ten? Because beyond that, a tail strike can occur.

I'll definitely be below decision altitude at that point.

Do you begin to assess the visual environment at DA or have you completed that assessment at DA?

 

[aterpster]

The laws of physics guarantee that!

Height loss varies depending on the airplane, but ILS criteria protect for a maximum of a 50-foot height loss below DA on a CAT I ILS.

 

[Captain]

Do you begin to assess the visual environment at DA or have you completed that assessment at DA?

The decision is made at the DA and it is made by looking out and seeing what you see. If were talking about the split second it takes to recognize the inside of a cloud and send the signal to my arm muscles to advance the power then it's fine and compliant.

If were talking about looking up...searching left, then right, maybe left again...is that it??? Then no, that is not compliant. It's a look up and decide...that's it and it takes no time. The decision has to be made AT the DA...not below it. That doesn't mean you have to 'pre-decide' to make sure it's technically at or above DA.

 

[John Collins]

Someone with fast response times can respond to an input and make a movement within .2 seconds, someone who has slower response times can do this within a half a second. Of course this assumes the individual is ready to act and doesn't have to think about it. When I am making an approach to minimums, I have already thought about it and am primed to act. In other words, I just need to make the decision, then act. Minimums are not a surprise and I am expecting to go around. It is a hair trigger or "immediate" response at the DH once the decision is made. Your hand is already on the throttle. In single pilot operation, you can't start looking for the runway at the DA, you have to have included looking for the runway in your scan prior to reaching the DA, so you can make your decision no later than the DA. Your response to the DA decision to miss the approach should be immediate where immediate is in terms of human response times. The response may take several seconds to fully actuate, but it should be initiated immediately. For me that is pitch up, power up, positive rate, gear up. If you initiate the response immediately at the DA, there will be some short lag for the inputs to be applied and the aircraft to begin to respond, and the momentum and flight path of the aircraft will take you below the DA, which is acceptable. The TERPS provide up to 161 feet of a level obstacle clearance below the DA to account for the sag thru and at the highest speed for a given category, the 40 to 1 obstacle slope will not kick in until about 16-17 seconds of flight, long after you have established your climb and are back above the DA.

 

[Greg Bockelman]

There is the PG/C definition, which is ICAO-speak, but there has been harmonization in this area:

DECISION ALTITUDE/DECISION HEIGHT
[ICAO]− A specified altitude or height (A/H) in the
precision approach at which a missed approach must
be initiated if the required visual reference to
continue the approach has not been established.

Note 1: Decision altitude [DA] is referenced to
mean sea level [MSL] and decision height [DH] is
referenced to the threshold elevation.

Note 2: The required visual reference means that
section of the visual aids or of the approach area
which should have been in view for sufficient time
for the pilot to have made an assessment of the
aircraft position and rate of change of position, in
relation to the desired flight path.

Thank you. That does not go against my understanding of the reg.

 

[DouglasBader]

Do you begin to assess the visual environment at DA or have you completed that assessment at DA?

The visual environment is being assessed all the way down the approach. In my current usual environment, that assessment is being performed by the pilot not flying, who is half-in, half-out of the cockpit, closely monitoring the approach on instruments, but at the same time looking for any signs of the things which will allow the approach to continue.

If the approach lights or runway environment isn't in sight at decision altitude, then a call is made: "No contact, go around!" Upon receipt of that announcement, the go-around is initiated. If I'm approaching minimums, I'm looking for that call, and If I don't get that call, I'll be peeking and querying. I may hear "approach lights in sight," to which I will respond "Continue." I may hear "Runway in sight, twelve o'clock," to which I respond "Landing."

In any event, I don't make up the decision to go around until I've arrived at minimums. I've I've decided to go around in advance, then what's the point of conducting the procedure in the first place, other than perhaps an exercise in futility?

It's expected that I will continue below minimums while taking whatever action may be necessary. If the procedure is continued below Cat 1 mins to 100', and I don't have the runway environment in sight, of course the go-around is commenced then. Where this occurs, it's crucial to maintain the electronic glidesope because almost certainly the main gear will be touching the runway during the go-around.

 

[Captain]

Whenever I do go missed I make the call at DA and I don't think I've ever gone more than 50' below the DH. That's not much and well within TERPS protected airspace.

 

[DouglasBader]

I don't think I've ever looked at the altimeter at that point to see how much altitude has been lost. My transition goes back to the attitude indicator to set pitch while calling for or setting power, noting airspeed,and looking for a positive climb.

If you've passed Cat 1 mins of 200' (or as published" and are going lower based on only the approach lights in sight, you'll be executing the missed at a lower altitude, and that's when it's very possible to strike the gear. Particularly on the aircraft I fly, there's a lot of airplane behind me and below me, and it's a lot of mass headed down hill. I'm 630,000 lbs when landing at max gross, which is most of the time, typically approaching at about 800 fpm, and one doesn't simply change that to a positive climb gradient in an instant.

 

[Everskyward]

"Somewhat below" is a little nebulous.

It's a bit nebulous because it depends on a lot of factors. You yourself said the airplane you fly might touch the ground doing a missed approach from DA. A 172 wouldn't even come close if the missed approach was executed properly.

 

[Captain]

It's a bit nebulous because it depends on a lot of factors. You yourself said the airplane you fly might touch the ground doing a missed approach from DA. A 172 wouldn't even come close if the missed approach was executed properly.

He wasn't speaking of a Cat I approach. I think he was speaking of Cat IIIa at least.