747 aiming point - Following G/S or VASI's
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747 aiming point - Following G/S or VASI's
Can someone please answer the anomaly of the eye height from the 747 cockpit and what happens if you follow VASI's or the G/S down to the runway ...
Should one see three whites + one red short finals?
If the ILS G/S is followed all the way down why doesn't it land you short?
On a visual what part of the touchdown zone are you aiming for?
Should one see three whites + one red short finals?
If the ILS G/S is followed all the way down why doesn't it land you short?
On a visual what part of the touchdown zone are you aiming for?
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As im sure you are aware, the indication that the pilot gets from the PAPI is
the position of his eyes with respect to the glide path, not the rest of the aeroplane.
On an ICAO aerodrome chart next to the position of the PAPI will be a
number called the minimum eye height (MEHT). This is the distance between the lowest indication on glide path indicator and the
ground when the pilot’s eye is over the threshold (basically the PAPI and the glide path indicator are showing the glide path with respect to the pilots eyes and not the lowest part of the a/c)
the position of his eyes with respect to the glide path, not the rest of the aeroplane.
On an ICAO aerodrome chart next to the position of the PAPI will be a
number called the minimum eye height (MEHT). This is the distance between the lowest indication on glide path indicator and the
ground when the pilot’s eye is over the threshold (basically the PAPI and the glide path indicator are showing the glide path with respect to the pilots eyes and not the lowest part of the a/c)
The normal MEHT is 50 ft. On a 300 ft/nm glide path this equates to 300 m distance, therefore the aiming point and the origin of the PAPI beams must be not less than 300 m from the threshold. Where larger aeroplanes such as a 747 use the aerodrome the MEHT is increased because of the greater distance between the pilot’s eye and the bottom of the main
gear. For example at Heathrow, the MEHT is 70 ft. This means the aiming point will be 400 m from the threshold. An alternative to moving the aiming point along the runway is to increase the glide path angle.
At least thats what they teach you in the ATPLs.
gear. For example at Heathrow, the MEHT is 70 ft. This means the aiming point will be 400 m from the threshold. An alternative to moving the aiming point along the runway is to increase the glide path angle.
At least thats what they teach you in the ATPLs.
The 747 has two sets of GS aerials. On intercept you will probably be using the one mounted on the front pressure bulkhead under the radome. When the gear is lowered, the ones on the front of the gear ddor are used. This increases the height between the actual GS and the pilot's eye line.
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Both Rainboe and Dan are correct about the GS receiver antenna switching from the nose to the leading edge of the nose gear doors. If you watch carefully in the cockpit you can see the change. While the usual minimum TCH (threshold crossing height) is 50 feet, in the B747 an on-glide slope indication will have the MLG across the threshold at 47 feet – unless there is some anomaly that shows up on the approach chart. Most B747 pilots use the PAPI (or VASI for those few places where it might still exist) to give the “extended” touchdown location – and that is usually the 3 white / 1 red (or white over red over red) until you get close enough to see what part of the runway doesn’t move on the windscreen – and then adjustments can be made if necessary to put that point at 1500 feet. Approximately 1½ to 3 seconds through the flare, then holding it level at the end of the flare for no more than 3 seconds should have the main gear on the ground between 2000 and 2500 feet down the runway with a very comfortable (i.e., slightly firm) touchdown. I also agree with Rainboe about the reliance on the verbal callouts – but I concentrate on how fast they come as a clue as to when to start the flare (usually about 30 feet) and how quickly to flare. I still have to find level flight on my own.
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We've let out the secret of landing a 747! The gap between 30' and 20' calls! You get to know eactly how long it should be, if it gets a shade too short, pull a little harder- a shade too long, pull a little less!
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Rabbit is spot on the GS antenna issue.
Different pilots and operators use different PAPI/VASI tracking technique.
For PAPI, we go 2 white/2 red down to 300-500' then 3 white and below 200' we usually see 4 white, and that's ok.
For VASI, if a 3-bar VASI is available, we go for the top 2 lights all the way. If not, we only rely on it down to 500' (where we have to be stabilized on visual), then it's all guess work, basically keep doing what you did before...
Then you have a good cue of the threshold lights dissapearing down the window at about 100', then actually crossing it at 50' you have the TDZ marks at the bottom of your windshield.
Then I listen to the RA callouts, trying to judge the rate he's calling 30, 20, 10.
Different pilots and operators use different PAPI/VASI tracking technique.
For PAPI, we go 2 white/2 red down to 300-500' then 3 white and below 200' we usually see 4 white, and that's ok.
For VASI, if a 3-bar VASI is available, we go for the top 2 lights all the way. If not, we only rely on it down to 500' (where we have to be stabilized on visual), then it's all guess work, basically keep doing what you did before...
Then you have a good cue of the threshold lights dissapearing down the window at about 100', then actually crossing it at 50' you have the TDZ marks at the bottom of your windshield.
Then I listen to the RA callouts, trying to judge the rate he's calling 30, 20, 10.
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Thanks for the replies ...
I was always taught -
300ft = Minor lateral corrections
200ft = Ground effect - resist climb tendency
100ft = Should see threshold (if not HIGH .. GA).
50ft = Should not see threshold (else LOW = GA).
30ft = Flare, minimal amount ... 2deg .. close taps ..
Although I rely heavily on the 50 and 30ft calls to judge when to iniate the flare, I still flare visually and feel I can judge the pitch and ROD from the their to touchdown .... I remember my first ZFT landing - at 50ft I looked out and had a huge think bubble saying - No it cant be! Its amazing just how quickly one gets used to the eye height ......
Re. VASI/PAPIs and going 3 whites 1 red at the latter stages - I find the ground effect around 200ft invariably nudges one on to that profile .....
I was always taught -
300ft = Minor lateral corrections
200ft = Ground effect - resist climb tendency
100ft = Should see threshold (if not HIGH .. GA).
50ft = Should not see threshold (else LOW = GA).
30ft = Flare, minimal amount ... 2deg .. close taps ..
Although I rely heavily on the 50 and 30ft calls to judge when to iniate the flare, I still flare visually and feel I can judge the pitch and ROD from the their to touchdown .... I remember my first ZFT landing - at 50ft I looked out and had a huge think bubble saying - No it cant be! Its amazing just how quickly one gets used to the eye height ......
Re. VASI/PAPIs and going 3 whites 1 red at the latter stages - I find the ground effect around 200ft invariably nudges one on to that profile .....
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Just a question here for the 747 jocks from an airline aspirant still flying light twins...
My experience with flying, as with most things in life, is that there is no substitute for repetition when learning a manual skill, and landing/manoevring an aircraft is no different. There's no doubt your 200th landing in a given aircraft is much better than your 20th (on average!).
My question is, 747s are typically used for very long sectors - and getting longer - in which you will likely only do one landing per shift, translating to perhaps 10-20 landings a month with many long-haul carriers. A short-haul B737/A320 driver might do 80 or more landings a month, and light twin guys like me might do 120-150. Skydive pilots can do 300.
How do you get so good at landings with relatively little "practice?". With such relatively long gaps between landings, it must be harder (than for short haul) to fine-tune your techniques , and therefore it must take years to get really good.
I mean this respectfully, I'm not taking the piss, I'm just interested to know.
My experience with flying, as with most things in life, is that there is no substitute for repetition when learning a manual skill, and landing/manoevring an aircraft is no different. There's no doubt your 200th landing in a given aircraft is much better than your 20th (on average!).
My question is, 747s are typically used for very long sectors - and getting longer - in which you will likely only do one landing per shift, translating to perhaps 10-20 landings a month with many long-haul carriers. A short-haul B737/A320 driver might do 80 or more landings a month, and light twin guys like me might do 120-150. Skydive pilots can do 300.
How do you get so good at landings with relatively little "practice?". With such relatively long gaps between landings, it must be harder (than for short haul) to fine-tune your techniques , and therefore it must take years to get really good.
I mean this respectfully, I'm not taking the piss, I'm just interested to know.
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..Well, Transgender Dragon, I'm not sure where you get 10-20 landings a month from?... I manage 2, maybe 3 if I'm lucky, and I'm a full-time 747-400 shag working for a fairly 'high profile' outfit.
My landings are generally like a feline urinating on velvet, which, FWIW, is not the correct technique - (slightly firmer is rigourously taught by the knob jockeys.)
How do I manage 'it', with so 'little practice'? - sheer ability mate!! - pure and simple - Oh, and about 12000hrs logged, 8000ish of which I have spent in the cruise thinking about the landing. 50, 30, (2 fingers) 20, 10, .......release of pale yellow liquid on said material.
..and I'm not taking the piss either.
nurj
My landings are generally like a feline urinating on velvet, which, FWIW, is not the correct technique - (slightly firmer is rigourously taught by the knob jockeys.)
How do I manage 'it', with so 'little practice'? - sheer ability mate!! - pure and simple - Oh, and about 12000hrs logged, 8000ish of which I have spent in the cruise thinking about the landing.
50, 30, (2 fingers) 20, 10, .......release of pale yellow liquid on said material...and I'm not taking the piss either.
nurj
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It's a fact!
I've been flying the 747 for *almost* three years. Got about 1500 hours in it.
And you absolutely hit the nail on the head. I average probably three to four landings per month.
And, like you said, I feel like I need a lot of repetition to master something.
Well, let's put it like this: Boeing has designed an incredible machine with practically no bad handling qualities. Only some important differences...
She's big, but quite nimble--and more importantly--verrrryyy stable. The most stable airplane I've ever flown.
All the credit goes to Boeing.
And you absolutely hit the nail on the head. I average probably three to four landings per month.
And, like you said, I feel like I need a lot of repetition to master something.
Well, let's put it like this: Boeing has designed an incredible machine with practically no bad handling qualities. Only some important differences...
She's big, but quite nimble--and more importantly--verrrryyy stable. The most stable airplane I've ever flown.
All the credit goes to Boeing.
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The San Antonio Death Tube.
The most unstable airplane I've ever flown would be the Fairchild Metroliner. Also known as the Sewer Pipe, Lawn Dart or Death Tube.
If you let go of that airplane it would, without any doubt, put you into a spiral in about 10 secs.
No exaggeration.
No yaw damper.
No autopilot.
No rest for the wicked.
I will say this: If you're trying to build a strong instrument scan, 500 hours in that thing is what you need...
If you let go of that airplane it would, without any doubt, put you into a spiral in about 10 secs.
No exaggeration.
No yaw damper.
No autopilot.
No rest for the wicked.
I will say this: If you're trying to build a strong instrument scan, 500 hours in that thing is what you need...
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ZeroZero & Nurj, thanks for the answers!
I've heard it said that the 747 is on of the best pilot's aeroplane ever built, sweet to fly in just about every respect. I suppose re the landings, you just gotta trust the machine, by the sounds of it! I've heard it said that the DC9/MD90/717 is also just about perfect for handling too.
As for the most unstable I've ever flown, I used to fly a Tiger Moth which had been rigged fairly poorly - still within tolerances, mind - and forever wanted to fly left-wing down. It would enter a spiral dive within about 8 seconds of hands-off flying, which sharpened your wits somewhat, as did the cruise prop it was fitted with, which would only give about 200ft/min climb after takeoff on a hot (35C+ day). I flew another which was much sweeter, still relatively hard work at times, but as much a delight as the other was a dog.
I've heard it said that the 747 is on of the best pilot's aeroplane ever built, sweet to fly in just about every respect. I suppose re the landings, you just gotta trust the machine, by the sounds of it! I've heard it said that the DC9/MD90/717 is also just about perfect for handling too.
As for the most unstable I've ever flown, I used to fly a Tiger Moth which had been rigged fairly poorly - still within tolerances, mind - and forever wanted to fly left-wing down. It would enter a spiral dive within about 8 seconds of hands-off flying, which sharpened your wits somewhat, as did the cruise prop it was fitted with, which would only give about 200ft/min climb after takeoff on a hot (35C+ day). I flew another which was much sweeter, still relatively hard work at times, but as much a delight as the other was a dog.
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I have flown the 747 for 10 years. In that time, I've landed 264 times and logged (by coincidence!) 7,470 hours, a good third of that spent in the bunk. An average then of 2.2 landings a month.
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http://www.airliners.net/open.file?i...next_id=NEXTID
http://www.airliners.net/open.file?i...oto_nr=14&tbl=
Check out the spotters by the fence!
http://www.airliners.net/open.file?i...oto_nr=14&tbl=
Check out the spotters by the fence!
Last edited by 763 jock; 10th May 2007 at 09:47.
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Those pics are outragous ... the crew should be called in for 'tea and no biscuits' for undershooting so much ... they are touching down well before even the threshold.
Suprised the spotters and fence havent been taken out ...
Suprised the spotters and fence havent been taken out ...