Dipping under the GS

[thebest]

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!

REFERENCE! THEBEST

 

[Lear70]

Lear70,

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

Actually, to tell the truth... no.

I *BELIEVE* that it's on the bottom of the fuselage halfway between the forward avionics compartment door (under the L1 door) and the wheel well with the VOR / VHF COMM 2 antennas, but I could be wrong. The training department didn't really stress it and I don't have my manuals here to reference, they're in my bag in ops.

That's one thing I liked about PCL; I had all the manuals downloaded in .pdf format and could open them on my computer and reference them at any time, including the FCOM's and the color diagrams and they were updated by the company regularly. AAI might have it too, but I haven't found them yet, just the self-study CBT CD.

 

[DC8 Flyer]

Lear

The reason I ask, is that Boeing may have designed the AP to compensate for the position of the antenna so that you cross the threshold at or near 50', by flying a dot low when inside the MM. On the DC8, the antenna is in the nose, and the airplane flies at about 1-2 degrees nose down on the glidepath so little compensation is needed. If your antenna is rear or in the tail even, there may be a need to compensate closer to the ground, maybe, just thinking out loud.

 

[thunderworm]

oh my god who cares as long as you can walk away.

 

[atldc9]

The glideslope antenna on the 717 is inside the radome. I've got several thousand hours in the 717, and feel pretty comfortable saying it does not intentionally fly one dot low on apporaches, either coupled or not. Locking it up and flying the needles will take the GS antenna to where the GS intersects the runway. Without flaring, the mains will touch down short of that point. There is a nice diagram in hte training section of the 717 AOM that shows the exact numbers.

It is poor technique to duck under. Go on over to the schoolhouse and preach the duck under technique and your proverbial pee pee will get smacked.

Lear, move the duck-under question over to the in-house training department web site if you think it will fly.

 

[Lear70]

The glideslope antenna on the 717 is inside the radome.

Cool stuff. Good to know, thanks.

I've got several thousand hours in the 717, and feel pretty comfortable saying it does not intentionally fly one dot low on apporaches, either coupled or not.

Ummm... I wasn't stating an opinion, I was stating FACT.

We flew 4 different aircraft over a 3-day trip. Every single one of them did exactly the same thing INSIDE the MM. At about 200 feet the descent rate picked up just a bit, at 100 feet we were 1/2 a dot low, at 50 feet we were 1 dot low, then the aircraft rounded out and touched down at the 1000 foot marker.

Every single time. Period. End of sentence.

I wish it was legal for me to leave my camera phone on and film the PFD during the approach and I'd post the video. Go fly it and tell me what it does.

Locking it up and flying the needles will take the GS antenna to where the GS intersects the runway. Without flaring, the mains will touch down short of that point. There is a nice diagram in hte training section of the 717 AOM that shows the exact numbers.

Again, I'm telling you what it does in the aircraft. Go fly it next time and leave it in autoland and watch it inside the MM. On the next approach, hand-fly it and lock yourself into those F/D cues and watch it do the same thing.

The question I have is: are you sure Boeing didn't DESIGN it with that in mind? Maybe the reason it pitches over and goes below the glideslope at the end is to compensate for the fact that the wheels are probably 30-40 feet lower than the glideslope antenna if it's in the radome.

Possibly THAT is why on an autoland you cross the references at the RA you're SUPPOSED to?

It is poor technique to duck under. Go on over to the schoolhouse and preach the duck under technique and your proverbial pee pee will get smacked.

Lear, move the duck-under question over to the in-house training department web site if you think it will fly.

I certainly would if I knew how to get onto that board. I also don't have log in info for the NPA board either, but that's my own fault for not dropping my stuff by whatshisnames v-file (I forgot his name actually).

Again, I'm not preaching a "duck-under" maneuver. That is an unsafe IMC maneuver done by wilfully flying low on the Glideslope while still in IMC conditions and I DO NOT condone that.

What I DID say, and will CONTINUE to say, is that it is legal AND safe to take up visual reference to the airport once INSIDE minimums and land the aircraft, even if you end up one dot low as you cross the runway threshold.

I'm sorry if you don't like that, I didn't make the rules, I just follow them, and there's nothing that says I can't. The regs and the AIM are on my side.

 

[Rez O. Lewshun]

I just reviewed Fly the Wing by Jim Webb, Professional Pilot by Lowery (including undershoot problems) and the FAA's AC61-21A. Those are three refrences for THEBEST in addition to company and aircraft manual, which state no going below.

I just can't take someones word that "Boeing engineers agree with me" as fact. Convienent that you have no log on and don't how to get to that board. I find that out of character...

These are simply documents that I'm referering to.. Or simple science. Not who's right but what's right. The references are in black and white.

 

[Junkflyer]

The 747 classicreads radio altimeter off the lowest point of the landing gear. A 3 degree glide slope crosses the threshold about 52 feet for the g/s antennae and 28 feet for the gear.( taken from our company manual) Our check airmen preached two things on the 74, do not get low, do not get slow.

 

[Rez O. Lewshun]

The 747 classicreads radio altimeter off the lowest point of the landing gear. A 3 degree glide slope crosses the threshold about 52 feet for the g/s antennae and 28 feet for the gear.( taken from our company manual) Our check airmen preached two things on the 74, do not get low, do not get slow.

It seems that low or slow as a no no applies to all aircraft. Energy management is key, specifically airspeed. Control the energy and that is all an aviator needs...

 

[Lear70]

Control the energy and that is all an aviator needs...

Really? Wow... guess I should have stopped studying years ago.

As far as not believing I don't have the log on information, I really don't give a rat's sh*t WHAT you believe or not. I've stayed off all the company sites for a REASON: I'm on probation.

Get it now? I thought since you are NEVER wrong, Mr. Infallible, that you'd know better than that. How disappointing.

I did have a couple guys PM me the info; I'll get around to it eventually.

 

[Rez O. Lewshun]

Really? Wow... guess I should have stopped studying years ago.

No comment :blush:

As far as not believing I don't have the log on information, I really don't give a rat's sh*t WHAT you believe or not. I've stayed off all the company sites for a REASON: I'm on probation.

Probabtion? I've always found that if an Air Line Pilot conducts himself professionally he doesn't have to worry about being on probation. In fact there is no real difference between his behavior during the interview, before and after probation....

Get it now? I thought since you are NEVER wrong, Mr. Infallible, that you'd know better than that. How disappointing.

......really, I am just referencing documentation. So it has nothing to do with me, rather the documents. In addition, I think there have been enough posters on this thread to conclude a consensus: Stay on GS, not below..

Actually, as childish as this thread has become it got me into the books and I've learned a bit more...

I did have a couple guys PM me the info; I'll get around to it eventually.

Eventually....:erm:

 

[Whine Lover]

What a bunch of techno dicks...Just fly the g-damn jet and shut the f up.

Love Ya,


YKW

 

[Lear70]

Probabtion? I've always found that if an Air Line Pilot conducts himself professionally he doesn't have to worry about being on probation. In fact there is no real difference between his behavior during the interview, before and after probation....

Suuuurrrre. Keep drinking the kool-aid, buddy.

......really, I am just referencing documentation. So it has nothing to do with me, rather the documents. In addition, I think there have been enough posters on this thread to conclude a consensus: Stay on GS, not below..

You are in error. Again. And will be unable to admit it. Again.

Go back and look again, Mr. Infallible, and see that there have been quite a few posters who have said that once inside minimums and transitioning to visual references, there is no problem going below the G/S.

Incidentally, I could probably take the time to look up your references and point out that neither said anything about remaining on the glideslop ALL THE WAY TO THE POINT OF TOUCHDOWN, but rather reference approach minimums, but then I really WOULD be geeking out, and I don't need to go that far to fly the airplane safely.

But you'll ignore those posts, just as you ignore anyone who disagrees with you on ANY topic.

Actually, as childish as this thread has become it got me into the books and I've learned a bit more...

You're right. It's childish. I should have left it alone a while back, I just can't get past how smug you always are. You must be just a PLEASURE to fly with for an entire month. uke:

 

[thebest]

I just reviewed Fly the Wing by Jim Webb, Professional Pilot by Lowery (including undershoot problems) and the FAA's AC61-21A. Those are three refrences for THEBEST in addition to company and aircraft manual, which state no going below.

I just can't take someones word that "Boeing engineers agree with me" as fact. Convienent that you have no log on and don't how to get to that board. I find that out of character...

These are simply documents that I'm referering to.. Or simple science. Not who's right but what's right. The references are in black and white.

jim webb, oh my god, i am so sorry! i take everything back.

 

[thebest]

I just reviewed Fly the Wing by Jim Webb, Professional Pilot by Lowery (including undershoot problems) and the FAA's AC61-21A. Those are three refrences for THEBEST in addition to company and aircraft manual, which state no going below.

I just can't take someones word that "Boeing engineers agree with me" as fact. Convienent that you have no log on and don't how to get to that board. I find that out of character...

These are simply documents that I'm referering to.. Or simple science. Not who's right but what's right. The references are in black and white.

What did they say...tell us?

 

[Rez O. Lewshun]

Suuuurrrre. Keep drinking the kool-aid, buddy.

Kool-aid? What kool aid is that? ALPA or company? Not sure if you know this but you can address any legitimate issue as long as you act professionally. If one doesn't know how to do that, then one probably lays low while on probation and makes a conscious effort to keep his/her mouth shut.

I've filed grievances and did active union work on probation, but that is just me.

You are in error. Again. And will be unable to admit it. Again.

I am wrong. My interpretation of the documents is wrong. But I shall always referer to the docs and fly the jet as directed. If I fly something different, like dipping below the GS, then I'll have a good reason. I don't have a good reason to go below.

Go back and look again, Mr. Infallible, and see that there have been quite a few posters who have said that once inside minimums and transitioning to visual references, there is no problem going below the G/S.

I'd be more concerned about knowing where the GS antena is on your jet, trying to calculate the GS presentation data on the PFD nad how you should make personal adjustments to correct for all the above. And then trying out your dipping below on the company message board that you just can't seem to find. I've never known you not to know where an applicable message board was located. Or the real test, going to your company school house and trying to convince the senior guys. But as usual you have a convienent excuse: you don't know where the training center is, the senior guys are EAL scabs and don't know what they are talking about, or they can't talk with you on Boeing engineer level....

But really who cares where the GS antena is? Just fly the jet as directed and one doesn't have to think about antena location, wheel truck location, etc...

Incidentally, I could probably take the time to look up your references and point out that neither said anything about remaining on the glideslop ALL THE WAY TO THE POINT OF TOUCHDOWN, but rather reference approach minimums, but then I really WOULD be geeking out, and I don't need to go that far to fly the airplane safely.

Ok. well, I have taken the time to read the references. And they do say to fly the airplane to the 1000ft marker. Not sure if professional pilots at this point need to be told not to duck under.

Dude, you could take black and white english reference and say it was chinese!

But you'll ignore those posts, just as you ignore anyone who disagrees with you on ANY topic.

Again.. it is not me. It is the references. Fly the Wing, Professional Pilot, FAA AC 61-21A, Company FOM and AOM, and of course, no reference that says to go below, except and FAR that says you can (not shall).

There is a reason why the 1000ft marker is the aim point. A history of undershoots.

You're right. It's childish. I should have left it alone a while back, I just can't get past how smug you always are. You must be just a PLEASURE to fly with for an entire month. uke:

As you know I am on reserve, so I piss off FO's by the dozen each month!

 

[thebest]

Kool-aid? What kool aid is that? ALPA or company? Not sure if you know this but you can address any legitimate issue as long as you act professionally. If one doesn't know how to do that, then one probably lays low while on probation and makes a conscious effort to keep his/her mouth shut.

I've filed grievances and did active union work on probation, but that is just me.



I am wrong. My interpretation of the documents is wrong. But I shall always referer to the docs and fly the jet as directed. If I fly something different, like dipping below the GS, then I'll have a good reason. I don't have a good reason to go below.



I'd be more concerned about knowing where the GS antena is on your jet, trying to calculate the GS presentation data on the PFD nad how you should make personal adjustments to correct for all the above. And then trying out your dipping below on the company message board that you just can't seem to find. I've never known you not to know where an applicable message board was located. Or the real test, going to your company school house and trying to convince the senior guys. But as usual you have a convienent excuse: you don't know where the training center is, the senior guys are EAL scabs and don't know what they are talking about, or they can't talk with you on Boeing engineer level....

But really who cares where the GS antena is? Just fly the jet as directed and one doesn't have to think about antena location, wheel truck location, etc...



Ok. well, I have taken the time to read the references. And they do say to fly the airplane to the 1000ft marker. Not sure if professional pilots at this point need to be told not to duck under.

Dude, you could take black and white english reference and say it was chinese!



Again.. it is not me. It is the references. Fly the Wing, Professional Pilot, FAA AC 61-21A, Company FOM and AOM, and of course, no reference that says to go below, except and FAR that says you can (not shall).

There is a reason why the 1000ft marker is the aim point. A history of undershoots.




As you know I am on reserve, so I piss off FO's by the dozen each month!

Ahhh, do you hear that? That is the sound of nobody giving a SH#T! PS I think of you every time I go below GS...91.129!