Dipping under the GS

[Patriot328]

The 757/767 series of Boeings have the RA calibrated from the main landing gear. The A320 series is the same. I would imagine nearly every modern airline is also done the same way.

 

[Lear70]

So the FAR's and the AIM not to mention other experienced pilots on here that do likewise aren't enough for you?

I give up. You're right, I'm wrong. Whatever. You just don't listen to reason, even when it's written in black and white by the controlling authority of our profession.

 

[Rez O. Lewshun]

So the FAR's and the AIM not to mention other experienced pilots on here that do likewise aren't enough for you?

I give up. You're right, I'm wrong. Whatever. You just don't listen to reason, even when it's written in black and white by the controlling authority of our profession.

Lear-

Based on your quote above the FARs state you should or shall go blelow the GS? The FARs only say you don't have to..... that doesn't mean you should.

The reason you, Lear, go below is you think it is good techinique and the FARs do not prohibit it.



But you have no reference that says a pilot should do this or that it is a good techinque. Again, you have to convince others that what you believe is good enough for them to agree!

There is no logial reason for a pilot to go below the GS... when

1. The perfromance data allows for a normal landing.
2. It is not common or mainstream technique.
3. There is no respectable reference.
4. Solid airmanship allows a pilot to fly on the GS to touchdown managing energy appropriately.


Somebody shoot me!!!

:beer:

 

[JohnnyP]

Ok, it is official. I am getting old. Questions like this now illicit the response out of me that I would see in my father and grandpappy. Are you stupid are just plain dumb? RTFM! Here is an idea. Instead of taking someone's word for it, who could be wrong be the way, why don't you get off your a$$ and do some research? Start with reading the FAR/AIM maybe....Not only is it a credible source, you might run across a few other things that you didn't know and increase your knowledge base. Imagine that, you could actually accomplish something that your spikey haired, backpack wearing dude friends have yet to undertake, professional continuing education! Taking shortcuts is no way to go through life kid.

Now, I have to go take my geritol, some back pills and try to get my morning BM out of the way before noon.

Dad, is that you????? I told ya not to come on here and embarass me! Thats hilarious you mention the morning BM. How many times did you get up during the night to pee? Only pokin fun..... I hope you can laugh with me

 

[FlyBoeingJets]

Lear-

Based on your quote above the FARs state you should or shall go blelow the GS? The FARs only say you don't have to..... that doesn't mean you should.

The reason you, Lear, go below is you think it is good techinique and the FARs do not prohibit it.

But you have no reference that says a pilot should do this or that it is a good techinque. Again, you have to convince others that what you believe is good enough for them to agree!

There is no logial reason for a pilot to go below the GS... when

1. The perfromance data allows for a normal landing.
2. It is not common or mainstream technique.
3. There is no respectable reference.

4. Solid airmanship allows a pilot to fly on the GS to touchdown managing energy appropriately.

If a pilot goes for an extra 500ft at MDW then he should go for an extra 500ft at every 6000ft runway.

What you are saying is I don't trust the performance numbers and/or my ability... And this is based on...... emotion.!

Not that you are going to change your mind, but perhaps you should check for grass, mud and approach lights in the gear on postflight!

Legal doesn't mean safe.

Do you have a reference that mainstreams dipping below GS as techniqueToday 15:22



Somebody shoot me!!!

:beer:

You are killing me Rez.

Lots of dead end logic up in that quote.

"Just because its legal doesn't mean its safe"

Just because its legal doesn't mean its unsafe either. You say going to a visual glidepath at 200 feet (on the glidepath mind you) and aiming somewhere between the 500' marker and glidepath intercept is unsafe?! Midway has displaced thresholds. Why do you assume you should "check the gear for grass". Sounds like you are the one basing your opinion on emotions. Just because someone does it differently, and legal, you bow up and talk down to them. Your mind is closing shut, first sign of aging.

Planes bigger than a 737 may have different issues, but the 737 does this just fine. The SWA guys who say its unusual to do must not fly with many Captains into shorter fields. And, BTW, this a VFR (read visual) maneuver. All the Captains I've seen so this are outstanding sticks and have no issues with it.

Its not ducking under either. Why, because I am visual. I am looking at the runway and the PAPIs. A duckunder is unsafe. Looking at the glideslope on your instruments and intentionally flying under the glideslope is wrong too.

Aiming just short of the 1000' markers is not unsafe under 200' AGL as long as you keep your descent rate in the normal range. If it was the FAA would ban it, period. But use your head and don't do it where visual illusions or poor vis would hurt you. It requires the same solid airmanship you recommend for landing in the zone on glidepath intercept, which is o.k. too, BTW.

I'm not trying to talk down to you, but you seem to be searching for some "mainstream" guidance or written technique on this. You're not going to find any. Flight experience, a little math. knowledge of your equipment and understanding TERPS lets you know what you can safely do. Knowing the FAR's lets you know what you can legally do.

 

[HighSpeedClimb]

Just to lighten up this thread....
http://www.youtube.com/watch?v=dGorCSnIHF4

http://www.evilchili.com/mediaview/6006/TSA_Training_Video__SNL

 

[thebest]

Legal doesn't mean safe.

Do you have a reference that mainstreams dipping below GS as technique

Logic goes a long way. If is a nice day and you can see obsticles, then go for it. That is why the feds wrote the reg that way. Say you stay on the gs at BUR, get to the 1000' mark and float. Well you can try to force it down and maybe stop, OR go around. GO AROUND, ok, now try to spool and large turbine engine up from idle.....by the way, you NOW only have 2500 feet or less left to stop in. OH shi#t!
Some like to stay on GS and hit the 1000' mark with no float, but who consistantly does that, NOT U OR ME! Speed cards are rough +margin of error for speed. So you go below airspeed now to make up for the float being on GS? Is that safer?

OR, dip below GS (pinkish) to do some of your floating between the numbers and 1000' ft mark, then touchdown and stop. Sounds logical to me! THEBEST

 

[Beanie]

Dad, is that you????? I told ya not to come on here and embarass me! Thats hilarious you mention the morning BM. How many times did you get up during the night to pee? Only pokin fun..... I hope you can laugh with me

Dangit Junior! For the last time get off that blasted computer and go mow the lawn!

 

[Rez O. Lewshun]

Logic goes a long way. If is a nice day and you can see obsticles, then go for it. That is why the feds wrote the reg that way. Say you stay on the gs at BUR, get to the 1000' mark and float. Well you can try to force it down and maybe stop, OR go around. GO AROUND, ok, now try to spool and large turbine engine up from idle.....by the way, you NOW only have 2500 feet or less left to stop in. OH shi#t!
Some like to stay on GS and hit the 1000' mark with no float, but who consistantly does that, NOT U OR ME! Speed cards are rough +margin of error for speed. So you go below airspeed now to make up for the float being on GS? Is that safer?

OR, dip below GS (pinkish) to do some of your floating between the numbers and 1000' ft mark, then touchdown and stop. Sounds logical to me! THEBEST

Sounds emotional to me! All you got feelings about the subject. No reference!

The runway performance data says 1000' marker.

C'mon guys... let's get factual and not feel good! This isn't Oxygen or Lifetime.

Still looking for that reference that says dipping below the GS is a good technique. Anyone? Anyone?

In fact many company manuals say you will stay at or above the GS at all times!

The system is designed to fly the GS to the 1000ft marker. If you don't know how to manage the energy so you get limited or no float then ask your sim instructor to help you out...

If you want to game the system so you feel better, go for it.. youre the PIC.


Still waiting for someone to shoot me! :uzi:

 

[JohnnyP]

Dangit Junior! For the last time get off that blasted computer and go mow the lawn!

Sometimes I miss those years where I was being barked at to do yard work. Where I live, the Taliban frown upon having well kept lawns.

Also, check out Citracel and Flax-seed bars, they work great

 

[GuppyWN]

...... after 5 pages - why don't you just fly the friggin' airplane. Use what you've got, don't what you don't.

Gup

 

[kngarthur]

For those of you who believe it's not possible to "dip" below and not float? In an extreme case, why not just pretend the 1000 foot markers are 1000 feet up, where the threshold is (slight power adjustment) ? You could maintain the same angle of attack and 3degrees gs the whole time. I personally feel that there is nothing unsafe about landing short of the 1000 foot markers. In fact I would argue that someone who can't think outside the box, would actually be unsafe by landing at the 1000 foot markers, especially without taking field length and runway conditions into consideration.

By reg I'd say it's completley legal unless you had a doughbag fed or checkairman on board.

 

[kngarthur]

Beano! your an *********** I guess your right, we should only stick to academics, and never get experienced professionals opinions?

 

[thebest]

Sounds emotional to me! All you got feelings about the subject. No reference!

The runway performance data says 1000' marker.

C'mon guys... let's get factual and not feel good! This isn't Oxygen or Lifetime.

Still looking for that reference that says dipping below the GS is a good technique. Anyone? Anyone?

In fact many company manuals say you will stay at or above the GS at all times!

The system is designed to fly the GS to the 1000ft marker. If you don't know how to manage the energy so you get limited or no float then ask your sim instructor to help you out...

If you want to game the system so you feel better, go for it.. youre the PIC.


Still waiting for someone to shoot me! :uzi:

You're the only one talking about emotions here sweet heart. My REFERENCE-( so you don't miss it this time) 91.129 It says stay on glide slope until lower is needed on order to make a safe landing. This is what the FEDS SAY! Its their technique! It's "factual not feel good" Hey how about your references. Don't Bi%TCH about references and then not give any yourself.......Oh hey, ya don't have any... do you!

 

[FlyBoeingJets]

No reference!

C'mon guys... let's get factual and not feel good! This isn't Oxygen or Lifetime.

Still looking for that reference that says dipping below the GS is a good technique. Anyone? Anyone?

In fact many company manuals say you will stay at or above the GS at all times!

Still waiting for someone to shoot me! :uzi:

You weird me out.

So follow your company guidance. But whatever it is, it still doesn't make it the only safe option. I hope YOU feel good doing it.

Reference--The logic center of the brain.



I can tell you're one of those guys that would never lie down when shot during a game of cowboys and indians. I can spot you guys a mile away. Those guys usually become lawyers because they will argue anything until you give up. Then claim victory when everyone leaves bored to tears.

 

[Rez O. Lewshun]

I was thinking about the other carriers I've flown at and recalled the company and aircraft manual stated no flying below the GS and/or VASI. So I looked in my current carriers company and aircraft manual and there it was in black and white. A concern was undershooting. Yet another reference.

I also noted stabilized approach critera and realized another arguement.

Sure the FAR say you can go below... if needed. Fact is, with Part 121 ops and specific runway data for each landing one doesn't need to go below. The performance at the 1000ft marker works fine.

Now I can't speak for the Yeagers on this thread, but the GS Dippers that I've flown with only manage to convert potential energy to kinetic as they pitch to the 500ft marker. Then they level off over the runway bleeding off energy...searching for the greaser...... touching down past the 1000ft marker as they finally reduce the thrust....




But hey if calculated performance data, company manuals and solid airmanship skills aren't good enough for you... go for it.. you're the PIC. Use that brain centered logic....while they can't reference it, I'm sure your company flight standards and the FAA will agree.... you da man!

 

[FlyBoeingJets]

One should always follow Company guidance unless safety dictates otherwise. Somehow you assume every company flying airplanes has the same rules in their manuals as your company does. The rules you grew up with and now fly under. You sure about that? I guess no one has any experience better than yours. You win.

And you still weird me out.

 

[Rez O. Lewshun]

One should always follow Company guidance unless safety dictates otherwise. Somehow you assume every company flying airplanes has the same rules in their manuals as your company does. The rules you grew up with and now fly under. You sure about that? I guess no one has any experience better than yours. You win.

And you still weird me out.

I grew up under Part 61 and 91. While they may still apply. I fly under Part 121.

Still haven't gotten a good arguement to dip below the GS. Just feel good reasons why based on a CFR that says not required... Nowhere does it say shall go below, or should.. just could. So just cuz you can you do?

Not sure why Part 121, landing perfomance calculations and FAA approved company manuals weird you out. Is following the rules, adhering to the system and not trying to game or max out limitations and regulations weird?

 

[8AF]

Incidentally, in both the CRJ and the 717 if you'll notice, staying on the glideslope has you crossing the runway threshold at 100 feet instead of the recommended 50.

If you'll go one dot below the g/s INSIDE the MM in these aircraft, you'll cross the numbers just as 'Betty' says "FIFTY". Incidentally, you'll also be right on the VASI / PAPI as well.

Perfectly legal, perfectly acceptable in VMC conditions under the "transitioning to land" provision in the FAR's and the AIM.

I have to agree with you; at least on the CRJ. I don't want to cross the threshold at 100' going into MDW or SBA. Good thing we pulled out from MDW.

 

[Lear70]

Amusingly enough, I was discussing this thread with the CA I was on this last trip, and he showed me something VERY interesting:

Staying on the Flight Director past a 200' DH will actually take you BELOW the g/s, but stay on the VASI in the 717.

It does this both on a manually-flown ILS and an Autoland ILS.

It does EXACTLY what I advocated, making the aircraft cross the beginning of the last set of approach lights at 100 feet (betty callout off the RA) at 1/2 a dot low on the G/S, then crossing the runway threshold at 50 feet at 1 dot low on the G/S, putting the aircraft in the flare over the Fixed-Distance Marker and touching down at the 1,000 foot point.

The entire maneuver, if the runway is VASI/PAPI-equipped, keeps the aircraft right on that visual approach aid.

Interesting how the ENGINEERS AT BOEING for this aircraft DESIGNED the aircraft to land exactly the way I have been doing it for the last several years on shorter runways (and advocated here).

How 'bout DEM apples?

In other words Rez, KMDA!

 

[Rez O. Lewshun]

Interesting how the ENGINEERS AT BOEING for this aircraft DESIGNED the aircraft to land exactly the way I have been doing it for the last several years on shorter runways (and advocated here).!

Wow. Hey everybody! I am just as smart as Boeing (MCD?) engineers and I didn't even know it!.. Actually I always did know it, but know I really really do know it! And so do you!! Who cares about calculated runway performance data!

If a pilot does not dip below the GS during a CATI approach why would he do it during VMC?

What does autoland do?

It is all about energy management. If you dip below the GS inside the MM (which by the way, many MM are being removed, so how do you know when you are really inside the MM) you are transfering energy, you are not dissapating or elimanting it. If you want to stop the jet get rid of the energy!

If you want to go for the 500ft marker then why not aim for it 5 miles out? You set up five miles out and fly the GS to the 1000ft marker, then, when you are a few hundred feet from it you change your aim point? Why? Cause the FARs don't prohibit it?

Lear, look the guy you are flying with is stuck with you in a confined space for hours.. maybe days. He is going to agree! I would too!

Still haven't gotten any references to dip below.... not just a FAR that says can. Anyone but Lear?
:beer:

 

[scoreboard]

Staying on the Flight Director past a 200' DH will actually take you BELOW the g/s, but stay on the VASI in the 717.

It does this both on a manually-flown ILS and an Autoland ILS.

Interesting, In our 3/700's, I'm pretty sure the F/D goes away at DH (200ft) for CATI, reinforces the going outside part of landing. Is the 717 autoland, maybe thats what is being displayed below dh, autoland guidance.

 

[AutoBus]

Excellent counterpoint Beanie....It is a shame that this type of guy will never get it or the pearl of wisdom you just tried to hand him.

BTW, who is checking GS in a "landing flare"? Last time I did a landing flare in transport cat. jet, it wasn't at the MM or DH, it was somewhere at or just before the runway, going for the landing zone. Prior to that, I was looking at the Runway Aiming Point Markers trying to keep the same rate of descent as I had for the last 5 or so miles to hold the GS.

On some Cat I runways the GS does not goto the touchdown zone. On some it does. It depends on the equipment used on the ground. Many Cat I only ILS's now have CAT III ILS equipment but, lack the other elements that permit CAT II or III approaches.

The FAA even allows you "autoland" currency credit on those CAT I only runways (as long as it's specfied in your ops specs)

 

[30West]

If a stabilized approach, visiual or IMC, is maintained, why would one need to "duck under"?
What are the benefits vs. the risks?
Never had a reason to do it, from C-152 up to DC-10.

The only thing that comes close is Quito. The Vasi and ILS glideslope to not match. The normal practice is to fly the ILS until the last few hundred feet, then transition to the slightly lower VASI, but NEVER below that.

Excessive speed results in float, and float eats up runway. That's what puts the ol' bluehairs into the tray tables in front of them. Fly the profile and it's a no brainer.

 

[Axel]

There are those among us who believe safety and efficiency are better served when everyone makes up their own rules as they go along. All of the research and knowledge (some of which was earned in blood) was all made up by a bunch of ****************************** bags who have no idea what is really going on because they are too old.

There are old pilots and there are bold pilots...then there's me: in a class by myself, who knows more through the virtue of my 23 years of life and 600 hours in the right seat than all of those old ****************************** bags could ever hope to know.

 

[b19]

Dip Below in Quito-All the time in a Heavy

Just curious about what all the experts had to say about dipping below on a short, high altitude South American airport with big rocks all around. If you fly a heavy into Quito you better dip below as you transition, and this is the safe, prudent, recommended procedure.

 

[ivauir]

Just curious about what all the experts had to say about dipping below on a short, high altitude South American airport with big rocks all around. If you fly a heavy into Quito you better dip below as you transition, and this is the safe, prudent, recommended procedure.

Get a clue.

The ILS into Quito has a DH over 600 feet, it is not germaine to this conversation.

 

[Lear70]

Lear, look the guy you are flying with is stuck with you in a confined space for hours.. maybe days. He is going to agree! I would too!

AAaaaawww, poor baby, Rez. Can't find any LOGICAL arguments to use in why the Boeing ENGINEERS designed the aircraft to do exactly what I was advocating, so you go on to personal attacks?

That's OK. We understand, as I'm sure many people on this board understand your M.O. perfectly, as so many politicians have used it over the years.

Still haven't gotten any references to dip below.... not just a FAR that says can. Anyone but Lear?

Sure. But the Boeing engineers don't count, right?



Just can't admit when you're wrong, can ya'?

p.s. 30 west, as the 717 descends below the g/s on an autoland (or as you fly the F/D and VASI guidance inside the MM), the autothrottles automatically retard to keep the speed steady. This all but eliminates any extra energy and results in zero additional float.

I have a tendency to turn the autothrottles off on climb and approach anyway. I like to keep my stick feel for the aircraft. As long as you manage the energy, you're not going to float. That's called good airmanship.

 

[DC8 Flyer]

Lear70,

Do you know where the GS antenna is on your airplane?

 

[RP 04]

The Boeing I fly follows the G/S until the flare starts (during auto land). I guess the Boeing engineers screwed that one up, at least according to Lear70.