Welcome to Flightinfo.com

  • Register now and join the discussion
  • Friendliest aviation Ccmmunity on the web
  • Modern site for PC's, Phones, Tablets - no 3rd party apps required
  • Ask questions, help others, promote aviation
  • Share the passion for aviation
  • Invite everyone to Flightinfo.com and let's have fun

Using GS,when not aligned with LOC (vis)

Welcome to Flightinfo.com

  • Register now and join the discussion
  • Modern secure site, no 3rd party apps required
  • Invite your friends
  • Share the passion of aviation
  • Friendliest aviation community on the web
Planning a proper briefing for a night visual approach is just as important as briefing for an approach to minimums. At our company, we are required to brief a full ILS for landing at night regardless of weather. Even if it is severe clear at night, you need to brief the ILS. It will definitely improve your situational awareness. I am not sure why the captain didn't mention the ILS prior to the approach. Look at your approach chart and know what the glide slope intercept altitude is over the fix and that will also keep you from being high.
 
Never do a night approach with out electronic or visual vertical guidance.

Probably best to clarify that. If electronic guidance isn't available, it's great to have a PAPI/VASI/PLASI, etc...but not absolutely necessary.

I've gone in and out of more than a few airstrips lighted by an automobile at one end or the other, flarepots, etc. No vertical guidance of any kind. If one adhered to the rule of never doing it, there are some very necessary operations that might never get done.

Perhaps a better rule would be to use vertical guidance whenever you can.

The glideslope is no different. Tune it up...I always tune in if it's available. But don't use it until you're in a position to use it. Don't follow it down when not on the localizer. A Squared's comments were exactly correct above, as were many others.

Try flying into Ketchikan, AK, and not being aligned with the runway as you start down. You'll try that once, if you're off a little to the right. Try approaching Flagstaff, AZ from the North and doing the same thing on the localizer.

Tune in, but use published routing and guidance before starting down. In mountainous terrain, you may be kept high a long time, at the MVA until you're over the navaid or fix that permits lower, but don't let any vertical guidance data from the ILS or otherwise coax you into going lower sooner. It's a bad idea, and a potentially fatal one. The glideslope is meant for use on the localizer, and nowhere else. Keep that in mind, and you'll do fine.
 
Enigma,

I was pretty sure you knew that, but what you wrote seemed open to a dangerous misinterpretation, so I thought I'd clarify.
 
Immelman said:
Am I the only one that is wondering what the heck you're doing on a visual approach w/o runway in sight? Was this not IFR?... Seems to me you need things in sight to be cleared for a visual...

Merely having the airport in sight can be very different from knowing exactly where the aircraft is relative to a 3.00 deg. slope from the runway end. Consider a night approach at an uncontrolled field to runway 9, approaching from the south. Overhead the field at 1500', turn downwind, turn base and now you have to look across a very wide cockpit through a narrow window that is pointed at the ground, the runway concealed by the cockpit ceiling and the Captain's large head - the poor FO has just about jacks#it for reference. So he might try to use some bonus glideslope indications, or start dead reckoning radar height vs descent rate vs groundspeed to try to make it all work. Our book says to brief the instrument approach at night, but doesn't require that it be flown - ergo I got to play this guessing game just last night.

Personally I think flying a full pattern in a turbine aircraft at a desserted, uncontrolled field at night is preposterous, but we do it night after night. Anybody with me on that one?
 
That's a big negatory there good buddy

<<Personally I think flying a full pattern in a turbine aircraft at a desserted, uncontrolled field at night is preposterous, but we do it night after night. Anybody with me on that one?>>

Nope. Not I.

I've lost the airport on a visual to an international airport in a metropolitan area after I flew thru a snow shower that couldn't be seen.

There was a Canadian C130 that tagged a hill in Resolute on a visual.

There are plenty of reasons to execute the full procedure. Did you read the entire thread?
 
"There are plenty of reasons to execute the full procedure. Did you read the entire thread?"

I think he was talking about flying a traffic pattern, not an approach.
 
Nope. And that's my final answer

...interesting segue...

but thanks Asquared.

I'm gonna stick with my original answer. The AIM says you should either enter the traffic pattern on a downwind from a 45 or go straight in.

I wouldn't ever make a base entry with a Fed on board.

Not only that but I'm willing to bet if the original poster had entered the traffic pattern on a downwind (configured and stabilized) he wouldn't have had the problem he did.

There's a reason why we do things the way we do them.
 
Personally I think flying a full pattern in a turbine aircraft at a desserted, uncontrolled field at night is preposterous, but we do it night after night. Anybody with me on that one?

Right. It's much better to do it in a piston powered airplane. After all, there's something magical about a turbine airplane that makes it a whole heckuva lot riskier. I've heard (but can't confirm) that entire passals of turbine airplanes explode in violent fireballs, wholesale, when attempting to fly patterns at night. It's been said that mountains have sprung up just to eat them alive, before settling back down to become a grassy plain, once again. Something about the high pitched frequency put out by a turbine engine. Flying a pattern in one is insane; the pattern Gods are driven crazy, and can react unpredictably.

Aside form that, never disturb a traffic pattern with a turbine powered airplane, espeically at night. They can be vicious when protecting their young.

Give me a break. Never flown a circling approach?
 
I wouldn't ever make a base entry with a Fed on board.
Huh?

Picture this: Landing runway 18, VOR is about 5 miles north of the field, roughly aligned with extended final. You're coming from the east, cleared direct to the VOR. Descending through 5000', approach asks if you have the field in sight, you do, and he clears you for the visual approach, contact tower. The other pilot calls tower & says that you're "on extended left base for the visual to 18." He thinks you're going to turn final about over the VOR (a square turn to final) and land. Are you saying that's unacceptable to you?

If I sound slightly incredulous, it's because there are plenty of places where exactly that sort of thing is done on a daily basis by major air carriers.

Now granted, if you're someplace with terrain close by that's higher than your normal traffic pattern, your SA needs to include some things that don't normally come into play, and you can NOT blindly follow a GS (ever -- they can be misaligned or fouled up, even where they should be reliable). However, for most places, you should be able to make a descending turn from base to final, rolling out on a normal glideslope, and be well, WELL clear of any terrain or obstacle problems! In those cases where that's not true, well, you need to have a thorough understanding of the situation before you get there, and execute an appropriate plan. But just like you don't fly into small Alaskan fields or Aspen or Jackson Hole or etc the way that you fly into Midland or Kansas City, you don't need to fly into Austin the same way you'd fly into Adak!

And, in that regard, looking at the GS indicator IS a suitable tool to use to evaluate your position relative to a 3 degree glidepath. Not used in isolation, not used if it's behaving erratically, not when other cues are telling you it's wrong, but there's no reason to outright ignore it just because you aren't yet centered up on the LOC. Under most conditions (normal visual pattern, base leg approaching final), the GS indicator is both stable and accurate before the LOC comes off the wall, and it can provide a much more precise position relative to the 3 degree plane than the mental math of DME-distance to threashold-altitude above TDZ.
 
I stand by my comment

I would not enter a traffic pattern on a base leg on a visual with a Fed on board to an uncontrolled airport.

Turning a five mile final is not a base leg. That's a five mile final and perfectly acceptable with good radio communication.

When I'm talking about entering a base leg I mean, you're configured and turning final between 500' and 1000' agl. That's a two to three mile final--and even though you may satisfy all the stabilized approach criteria you have just barged you're way into the traffic pattern.

It wasn't too long ago the FAA was even against the straight in approach. They felt the *only* way to join a traffic pattern was on the downwind from the 45.

Now there are two ways.

But even so, a few years ago there was a crew (major passenger carrier) violated for turning a two to three mile 'dog leg' to final at Kotzebue and called it a straight in.

The FAA said, Nope. Not for your size of airplane. You need to be on final five or six miles out.

All I'm saying is, if there's a Fed on board you better fly like it's Sunday afternoon and you're going for pancakes.
 
Mar, the problem in Kotz was not a base leg entry, the problem was a right base to a runway with a left hand pattern. There is nothing which prohibits a left base entry to a left pattern, you may not however enter a left pattern on a right base.

NTSB order

Notice the regulation cited is 91.89(a) which is the predecessor regulation to 91.126 and 91.127. 91.89(a) essentially said all turns to the left unless it's a right pattern.

The crew would have been on solid legal ground if they had done the same thing from the opposite direction.
 
Last edited:
Interesting document.

AA--I've never seen that document before.

Why were they making a *right* hand turn? They were approaching Rwy 26, correct?

Coming from either OME or ANC that's a *left* turn.

Either way, I'm not sure I agree a left turn would've left them on solid legal ground.

From the document: <<respondent's right-hand turn was made between 1 and 2 miles from the runway, it could not be considered a straight-in approach. NTSB Order EA-3523, at 7-9. It is introduced to show that: 1) a B-737 can "easily be established on a straight-in approach" within that distance (Petition at 9); and 2) that distance is consistent with B-737 requirements for circling approaches.>>

To me that reads like they're trying to prove a final of 1 to 2 miles is acceptable because the 737 is approved to circle at that distance--regardless of the direction.
 
Re: Interesting document.

mar said:

Why were they making a *right* hand turn? They were approaching Rwy 26, correct?


Not according to my understanding of the incident. Every discussion I've ever heard of this describes them doing a right base for RWY 8. The NTSB order doesn't explicitly state which runway was being used, but it does state repeatedly that the issue is a right turn to final. That, coupled with the fact that that the flight was almost surely arriving from either Anchorage or Nome, strongly suggests to me that it was RWY 8, as I have been previously lead to believe. Surely you'll agree that it would be awkward and inconvenient, at best, and have no operational advantage to position the airplane for a right base turn to final for Rwy 26, if arriving from either Anchorage or Nome?

Here's the issue as I understand it:

There is no question that it's illegal to fly a right hand pattern to a runway with a left hand pattern. The question is "how far out does a right turn to final stop being "right hand pattern" and become a "straight in approach".

lets take a look at a couple of hypothetical scenarios.

If you had two airports 50 miles apart and the runways were perfectly aligned, and you took off from one and flew a perfectly straight path to the other and landed straight in, you could not be found in violation of 91.89(a). 91.89(a) prohibits right turns, and you didn't make any turns, so the facts don't support a violation of 91.89(a).

Now, suppose that you made a right turn onto final for your landing runway 50 miles from the runway. Does that right hand turn constitute a violation of 91.89(a)? Clearly, that is absurd, and no one, not even the FAA, claims that a right turn to final 50 miles from the airport constitutes a right hand traffic patern.

So the question becomes, at what point does a right turn to final become a violation of 91.89(a) (now 91.126 (a) and (b) and 91.127(a) by reference) ?

If you turn right onto final 25 miles from the airport is that a straight in approach or a right pattern?

10 miles?

5 miles?

2 miles?

Obviously, at some point it becomes a right pattern and not a straight in approach.

In according to the order, the right turn to final "was made between 1 and 2 miles from the runway" This is apprently not disputed by the respondent.

As I understand it, the FAA argued and the NTSB held that a right turn to final must be made at least 5 miles from the airport to be considered a straight in, rather than a right pattern.

mar said:
Either way, I'm not sure I agree a left turn would've left them on solid legal ground. ?

Yes, a left turn would have left the captain with an absolute, bulletproof defense against a violation of 91.89(a). In order to violate 91.89(a) there must be a right turn. (or a left turn to a runway with a right pattern) Without a right turn, the FAA has no case for a violation of 91.89(a).

Now, your position is that a left base entry to a left pattern is not allowed. Perhaps perhaps not. I'm not conceding that point, but the NTSB case we've discussed sheds no light on that issue. That case centers around 91.89(a) which is completely irrelevant to the question of whether a left base entry to a left pattern is allowed. As long as you are making turns to the left you are in compliance with 91.89(a), or in the context of today's regulations, with 91.126 and 91.127.

So, in order to sustain a violation for a a left base entry, what regulation is going to be cited? There is no regulation which prohibits such an entry. There is only the AIM's recomendation. The only regulation which might be applicable is 91.13, careless or reckless operation. So we enter a grey area. There is no precedent I am aware of which establishes that failure to follow the AIM recommendations is, per se, careless or reckless. The FAA must demonstrate that such an action, is in fact, careless or reckless.

Could the FAA sucessfully argue that a left base entry is careless or reckless? Perhaps, if there were other supporting facts; failure to use proper radio procedures, conflict with other traffic, something like that, I'd say yes.

If you flew a left base entry and there were no traffic conflicts, you made all the recommended radio calls, and did everything corecctly, I think that the FAA would have a hard time justifying a careless or reckless finding against you on the sole basis that you didn't enter on a 45 to the downwind.

Food for thought: Entering the downwind on a 45 is, per se, a violation of 91.126 or 91.127 as applicable. You can't enter on a 45 without making a right turn, and you are only allowed to make left turns.
 
AA and Mar. Seems like old times. Good posts gentlemen. It's about time we got into a relevent aviation discussion.

8N
 
I don't know about you, my friend,...

...but I've had *way* too much time on my hands lately. Way too much sittin' around on reserve.

But I'm about ready to leave for the banana belt (I got a 1700 DLG/AKN).

:cool:

<<Food for thought: Entering the downwind on a 45 is, per se, a violation of 91.126 or 91.127 as applicable. You can't enter on a 45 without making a right turn, and you are only allowed to make left turns.>>

Listen, that was very funny. You'd make an excellent lawyer.

But back to the OTZ incident. My only memory of the whole thing was an article written about six years ago. Apparently some important facts were omitted because the only thing I took from that article was the FAA was bustin' their balls for announcing straight in but turning a two mile final.

The main thrust of the article was that's fine if you're flying a single engine Cessna but turbine powered transport aircraft should be established on final much farther out--like 5 or 6 miles.

I think if you hooked a right turn to final 8-10 miles out and announced a straight in there would be no problem with that.

There's always room for exceptions but that's why we use our best judgement--and that's why we get paid the big bucks, right?!?

Not to repeat myself but if I had a Fed on board I'd be taking things real slow and professional.

There's no reason to hook a two mile final let alone make a right hand turn.

I'm sure we agree. I think I just needed to explain why I used the example I did and where some of my misconceptions came from.

Fly safe!

[Editted to acknowledge 8N's comment. I agree. Thanks for saying so.]
 
Last edited:
your_dreamguy said:
We were coming in on base (we never did a downwind entry, so I never saw the runway) and I had the hardest time picking up the runway and runway lights. Subconiously, I stayed high. As I got closer, I ended up high and fast. We landed the plane but we nearly had to do a go-around and the Capt. was pissed. On the ground, the capt said he had put in the ILS freq. in my radio (and he did do that) as backup. He told me that I could have used the GS indications on base leg to get a good feel for descent and proper altitude on base (even though, we were not aligned with the LOC) because we were going visually.
Well it is technique, but there are rules in the AIM and you also have which Part you're operating under as well as your operations specifications your carrier is working under to consider as to whether this is legal or not. In Part 121 at my airline, what you did is most definitely not legal.

Now you must at all times have the airport in sight to do a visual approach. If you started this approach on the base without the runway in sight, you're not legal.

If you're on base and you don't have the runway in sight, ask the Captain if he has it. If he does, transfer control to him. But don't let an old fart make you do something that isn't legal. In this case you should have brought it to his attention that you didn't have the field, and if he's up on his stuff, he'll take the plane.

Is there PCL at this field? If so, always click up the lights (7 clicks in three seconds) to make sure they stay lit during your approach. You can always step them down as you fly towards it. If it was controlled, ask the tower to turn them up (usually they'll go so bright you'd wish you hadn't asked- but at least you'll have the field).

Next question, how far down did you land? That may not have been legal either. Remember, if you land a perfect 10 but it's 5,500 feet down a 6000 foot runway, you will flunk the course.

Finally, about using the G/S when off the LOC, you can use it to back up a solid visual, but it is not reliable. I'd rather do some quick math in my head and have some numbers at hand for targets based on the navaids available. Your landing starts in cruise. Remember, prior proper planning prevents piss poor performance.

Rule of thumb that will never get you in trouble: don't start down the slope until you're on the LOC. Otherwise, you're not in protected airspace when IFR. VFR, YOU take responsibility for obstacle clearance -and if you think I'm going to trust a wavering G/S needle, you're dead wrong.

But don't do what this Captain says and think that it's always going to work. Take everything you hear with a grain of salt, test it, keep what is good and throw away the rest. You can learn something from every Captain you fly with. Some you learn how to be, from others you learn how not to be.
 
Many glide slopes ”bends down” outside the coverage area and will place you too low. This have caused accidents.
 

Latest resources

Back
Top