Captain Toolbox (WARNING! LONG RANT!)
- Thread starter CapnJim
- Start date
CapnJim
Well-Known Member
You know guys, this has really become a dreaded 'technique thread'. We can go on and on about this one and no one is going to give, especially when the 'ol egos get going.
We're all prattling on as if no pilot has ever though of this stuff before, when actually, pilots have probably been ducking below slope or riding it rigidly down since the advent of instrument landing systems. We may as well be arging wheel landings vs. three pointers.
I'm almost always on the side of judment and fluidity to circumstances rather than ridgid adherence to the rules on matter what. This is likely to my own detriment since very few things in the world are black and white; you almost always need to find balance, and it's in finding and maintaining that balance that people describe as 'being in the zone' or 'having your game on'. If you swing to far to either side, you invariably loose something. Always maintain the slope? You may go off the end one day. Duck under? You may eat an obstacle. Balance, balance.
Or not. Whatever. Carry on!
<CapnJim sips his mojito>
We're all prattling on as if no pilot has ever though of this stuff before, when actually, pilots have probably been ducking below slope or riding it rigidly down since the advent of instrument landing systems. We may as well be arging wheel landings vs. three pointers.
I'm almost always on the side of judment and fluidity to circumstances rather than ridgid adherence to the rules on matter what. This is likely to my own detriment since very few things in the world are black and white; you almost always need to find balance, and it's in finding and maintaining that balance that people describe as 'being in the zone' or 'having your game on'. If you swing to far to either side, you invariably loose something. Always maintain the slope? You may go off the end one day. Duck under? You may eat an obstacle. Balance, balance.
Or not. Whatever. Carry on!
<CapnJim sips his mojito>
B767Driver
New Member
Mr_Creepy said:
Mr. Creepy,
I agree with you. I think there is very sound logic for a pilot to readjust the flight path at the MM to land earlier in the touchdown zone than the ILS glideslope will allow.
The ILS glideslope is only valid below the MM on ILS approaches that do not have a decision height. Below the DH on ILS approaches it becomes a visual maneuver...and while I would always reference and maintain the glideslope to touchdown on a normal landing, the point should be emphasized that the glideslope is a reference and the pilot's visual picture is primary for landing below the DH/MM.
There was an accident back in the '70's....DC10....can't remember the airline...but they went low on the glideslope and hit approach lights. However, there was no standard for G/S antenna location (as there is now...750' from the threshold)...and there was no published or standard TCH. Now...all of that stuff is standard...the glideslope will always provide a a minimum of 47' TCH and typically is 50'. Also, the TCH is now always published.
If you fly a bigger jet you must know the difference in the wheel base height to altimeter at the TCH. The jet I fly gives a lot of data in this area.
Also, consider these numbers. One dot glideslope deviation at the OM = 50'. One dot glideslope deviation at the MM = 8'.
If, on a contaminated runway, at the MM I adjust my flight path to fly one dot below the glideslope...I will have at least a 42' TCH...and a much improved opportunity to land a few hundred feet earlier in the TDZ. I know that as low as 25' TCH I should be okay as far as the wheels clearing the ALS.
FWIW, I don't like to call this a "duck under" maneuver. To me the term "duck under" implies that I'm at a minimum altitude and I do not have sufficient visual references insight...and I'm busting an altitude to try to see something. For example...being on G/S, below DH, without the necessary visual cues in sight...is a "duck under". In my example...I have the necessary visual cues in sight...I'm adjusting my flight patch visually to achieve a certain touchdown objective. If this adjustment entails a one dot glideslope deviation...I feel certain...knowing the feet of glideslope deviation and my wheel base height...that I'm safe as far as obstructions are concerned.
Now, back to what Mr. Creepy said...on a slippery runway...I want to be down and braking...especially since my data says I should be on the ground 1000' from the landing threshold and braking. I definitely think a slight adjustment of the flight path is good judgment to make this happen. Typical landing data gives perfomance based on NO Flare. To me this is unrealistic...as I've never seen anyone not flare an airplane under any situation. It always adds least 500' if not more to a typical landing.
One other piece of info...I did not realize...my jet's contaminated landing performance is based on FULL Reverse Thrust. I never new this before.
Jim,
FWIW, I appreciate the discussion on this topic, alot of it brought up by TonyC. It's made me think about this issue a little deeper and reevaluate my understanding of the issues involved in changing the flight path after the MM. All of us should realize the hazards present in landing data. A maximum performance stop is something that a lot of professional pilots would be unable to acheive given the prerequisites set forth in the data. Heck, even being within 1000' of minimum landing distance should have us employing what the typical line pilot would view as a maximum stopping effort. As we all know, every winter, there are a handful of jets several hundred feet off the end of the runway.
CapnJim
Well-Known Member
B767, you're right. The debate is the thing; maybe that's what can give us balance more than anything else. TonyC's style and delivery annoys the hell out of me, but I have to give it to him, a lot of the time I have to stop and say, "Hmm! That's a tough one to argue with. But he's ticked me off enough, I'll try to figure out a way!" And I invariably leave richer for the experience.
In that same light, I also appreciate the benefit of your experience and opinion. I somtimes feel as though you and I are divided along the lines of regional vs. mainline, and that's fair enough! I've only been in the regionals for a year, and the fact that you're driving 76's tells me you've been in this messy industry for a while, so man, I'm listening!
Preach brother!
In that same light, I also appreciate the benefit of your experience and opinion. I somtimes feel as though you and I are divided along the lines of regional vs. mainline, and that's fair enough! I've only been in the regionals for a year, and the fact that you're driving 76's tells me you've been in this messy industry for a while, so man, I'm listening!
Preach brother!
Mr_Creepy
Well-Known Member
I said there is no reg preventing it! Are you disagreeing with that now?TonyC said:Actually, you just keep saying that you can - - you haven't really showed us anything.
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Sometimes I think you are arguing with me just for the sake of arguing.
I don't like the "duck under" terminology. That is another story. I would like to stick to visual conditions, where you slightly increase your rate of descent to touchdown somewhere between the numbers and the fixed distance markers, solely for the purpose of extending your available braking distance.
I'm not advocating drastic maneuvers, just suggesting that 1 dot or less below the glideslope after the MM may be called for on a short runway.
... and yes - I do believe it is a judgement call.
My point was, you have told us that it is permitted, but you haven't explained exactly how it can be safely accomplished.Mr_Creepy said:
Believe me, I don't enjoy arguing with you - - it's too hard to keep you focused on one point.Mr_Creepy said:
I'm just in it for the subject. 
And some people don't like "cockpit." Oh well - - it is what it is.Mr_Creepy said:
I'm still waiting for a description of this manuever. Give me the lesson plan, talk me through it - - teach me.Mr_Creepy said:
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Chris_Ford
Well-Known Member
TonyC said:
One, I don't like how you hit *enter* *enter* *enter* *enter* then dot, so I always have to edit when I respond to you, and I also don't like how long-winded your responses are, and that you quote one line, write a paragraph, quote another, write another paragraph.
The key to being a good writer is to be succinct
/I know you didn't ask me, but I'm just griping
B767Driver said:
I don't have a textbook definition of "duckunder" handy, but I believe what you're describing is busting a minimum altitude. Ouuu, you even used those words - - busting an altitude.
I've always understood "ducking under" to mean going below glidepath, intentionally, in order to land earlier on the runway than you would had you remained on the glidepath. Do I need to get a refund on my training?
No, don't answer that.
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B767Driver
New Member
TonyC said:
1. I have never touched down prior to 1000' There is no official procedure, per se, that you are looking for me to give you. There is only data available to assist the pilot's judgment for obstacle clearance at the threshold. This data suggests that the mains will touchdown at 650' given a TCH of 25' which is as low as you should ever find yourself at the threshold. Personally, this is too low for my comfort. If you needed the extra runway...(no flaps, icy runway, short runway/emergency landing, etc)...this data will help in the decision making process. On a contaminated runway, I would look to cross the threshold somewhere around 40 to 45' for a more assured touchdown close to 1000'...I always have some float in the flare...I never contact the runway from the G/S rate of descent without some effort to break the 750' descent rate.
2. I think wind shear/location physical feattures, etc, play a large role in possible G/S deviations at this point and should be weighed against the need for using a maximum amount of runway. Obviously, under normal situations, the need for more runway is less critical than these identified variables.
3. While I'm not in the training department, or an expert on training regs, I don't think Part 121 Appendix F applies to my company, as we are FAA approved AQP. We do not take Proficiency Checks as per Appendix F. However, the AQP curriculum requires demonstration of a no flap/no slat visual landing without the aids of electronic glideslope or localizer guidance to include PAPI/VASI or FMS. The landing must culminate in the TDZ early enough to accomodate the landing distance requirements. Typically, the aim point is 1000'.
B767Driver
New Member
TonyC said:
I haven't busted a minimum altitude. I satisfied that at the DH.
B767Driver
New Member
CapnJim said:
Well, I was a regional pilot too. I'm working harder not to come across as being against regional pilots...but I definitely don't like some of the practices going on at most regionals. Mostly, hiring rock bottom mins for obscenely low pay.
No preaching from me...if I feel I can contribute to the discussion I will. I enjoy all things aviation and pilot related...so I enjoy the "hangar" talk. I learn lots, here...it's mainly why I enjoy Doug's website...for a bit of professional development. But am working harder at maintaining a professional demeanor and definitely preserving the dignity of all those involved. To do otherwise demonstrates a lack of character in my opinion.
pscraig
Well-Known Member
CapnJim,
We have a few of those here down in the Southern base as well. Usually egocentric nervous guys who spent too long in the right seat dreaming of how they would be captain. And the FFDO part too-most of those guys are OK, some are the ones that read Shotgun Quarterly in flight and are a little paranoid. There's one who did something similar to me back in August, and we mutually agreed not to fly together again. Without going into details, I should have gone to Pro Standards. Taking the controls from someone in such a critical phase of flight is utterly stupid. And for what its worth, I usually fly the EWR approaches a little fast myself this time of year, there is usually some mild windshear.
We have a few of those here down in the Southern base as well. Usually egocentric nervous guys who spent too long in the right seat dreaming of how they would be captain. And the FFDO part too-most of those guys are OK, some are the ones that read Shotgun Quarterly in flight and are a little paranoid. There's one who did something similar to me back in August, and we mutually agreed not to fly together again. Without going into details, I should have gone to Pro Standards. Taking the controls from someone in such a critical phase of flight is utterly stupid. And for what its worth, I usually fly the EWR approaches a little fast myself this time of year, there is usually some mild windshear.
CapnJim
Well-Known Member
pscraig, I hope we can meet someday. You seem a good guy.
I think a lot of guys get into aviation for the 'glory', and when they find out there's not so much glory left, the only way they find to get thier self-approbation is through subjugation of anyone and everyone they feel superior too, which is almost everyone, including rampers, gate agents, passengers, flight attendants, and hapless first officers. It's a dangerous personal failing to believe that you're without fault, because people are reticent to correct you. I fell victim to it with Captain Toolbox but everyting worked out; other people in other flights have died.
It's a wonderful thing to have extensive knowledge and experience in aviation. Knowledge and experience are power, but how you use that power defines the quality of person that you are. Some guys get it, some don't.
I think a lot of guys get into aviation for the 'glory', and when they find out there's not so much glory left, the only way they find to get thier self-approbation is through subjugation of anyone and everyone they feel superior too, which is almost everyone, including rampers, gate agents, passengers, flight attendants, and hapless first officers. It's a dangerous personal failing to believe that you're without fault, because people are reticent to correct you. I fell victim to it with Captain Toolbox but everyting worked out; other people in other flights have died.
It's a wonderful thing to have extensive knowledge and experience in aviation. Knowledge and experience are power, but how you use that power defines the quality of person that you are. Some guys get it, some don't.
Mr_Creepy
Well-Known Member
I'd like to meet everybody on this thread. We could really hash this one out over some single malt scotch and a nice cigar.
Tony - the maneuver is pretty simple. At DH reduce backpressure a little bit and let the plane increase rate of descent a few hundred feet a minute.
When you hit 30' on the radar altimeter (B737 number) - flare!
Tony - the maneuver is pretty simple. At DH reduce backpressure a little bit and let the plane increase rate of descent a few hundred feet a minute.
When you hit 30' on the radar altimeter (B737 number) - flare!
Mr_Creepy said:
Hmmmmm...
Just reduce the back pressure, huh?
I try to have the pressures trimmed off, so I assume an increase in forward stick pressure would have the same effect - - the nose lowers.
I didn't detect any mention of a corresponding power adjustment. Absent any power adjustment, I would think that in addition to increasing the descent rate, the airspeed would also increase.
And then the flair - - you used 30 feet for the 737. Is that the normal point, or did you begin the flare early to account for the increased airpseed and descent rate? Do you flare at the same rate (degrees of pitch change per second) or do you flare at a faster rate to account for the increased descent rate? It seems to me that you would either have to flare faster, flare earlier, or accept a faster descent rate at touchdown (harder touchdown with greater possibility of bounce) - - it's not clear from your description which is the case.
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CapnJim said:
OK, so you got me. I'm not confused at all - - I was just trying to be polite. For your sake, I should have said, "You have contradicted yourself. First you say, in describing your version of a 'duckunder', that you are busting a minimum altitude by descending below the DH without adequate visual reference, and then in the next post you claim you have not busted a minimum altitude because you have satisfied the requirements of descending below DH."
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