Ask The Pilot

[jb747]

What they are supposed to do is to stop the descent at 800' (or so, whatever the minima is), and to then fly the track until they reach a point at which it intercepts the 3º glide slope. What they have done is a continuous (roughly 3º) descent from the end of the approach. That would be appropriate at most straight in approaches, but the entire idea of this particular approach is simply to put you in a position from which you can fly a visual arrival. The buildings must have looked very close. And it begs the question of just what they were looking at. The aircraft shows the distance to run to the runway, and it will also show a calculated 3º glide path, even in this sort of approach.

Most approaches in the world are now continuous 3º approaches. Level segments are very rare, but they do exist in offset arrivals like this. The reason so much effort was put into removing level segments is that they can be dangerous...nevertheless, they are not difficult to fly. It's the same approach, with different visual segment for 13L and R.

 

[Quickstatus]

Is usual approach to DME a continuous 3deg glideslope?

What would the A380 navigational displays be saying during the JFK and DME approaches.

As an aside how much bank would be required to turn for finals at JFK for "Carnasie" approach? Seems like a tight turn?

If the pilots had to fly visually to 13R/L, at some point the AP would have to be turned off. Something here? Did the automatics play a role here - were they on when they were not meant to be?

 

[jb747]

Is usual approach to DME a continuous 3deg glideslope?

The normal slope is 3º, doesn't matter what the approach form.

What would the A380 navigational displays be saying during the JFK and DME approaches.

I've never looked at it in the aircraft...I will if I remember on Saturday. Most likely it would show a straight line to the end of the approach, then a discontinuity, and the extended centreline as a separate line. The company may have had a track built (for the FMC), but that's not necessary to fly the arrival.

As an aside how much bank would be required to turn for finals at JFK for "Carnasie" approach? Seems like a tight turn?

Not really. The turn point can be varied depending upon the wind. I expect that 15º-20º in nil wind would work.

If the pilots had to fly visually to 13R/L, at some point the AP would have to be turned off. Something here? Did the automatics play a role here - were they on when they were not meant to be?

Well, the automatics may have played a role in that they SHOULD NOT be used. You can maintain the a/p on until reaching the actual descent point, but it should be off by 50' below the MDA. The turn is meant to be manually flown. The autothrust will remain on the whole time though.

 

[Quickstatus]

I wonder when they did the final turn to 13L, did they make the turn manually?

 

[jb747]

I wonder when they did the final turn to 13L, did they make the turn manually?

I expect so. It's the sink rate they've messed up, not the turn.

 

[Quickstatus]

I expect so. It's the sink rate they've messed up, not the turn.

FR24 suggests they had already commenced the final turn when they went below minima?

 

[jb747]

FR24 suggests they had already commenced the final turn when they went below minima?

It's not just a case of the minimum altitude. The minima is reached at point called the 'missed approach point'....you need to be visual at that point. The tracking after that point is supposed to be visual, but because of the geometry of that particular approach, you need to maintain altitude for about a mile after the MAP, before you intercept the 3º path. At that point you'll have curving track and a simultaneous descent.

 

[Quickstatus]

So they went below minima before MAP (= DMYHL waypoint?) but didnt realise it until told be ATC. Would there have been a "minima" annunciation at some point?
It was a night arrival so buildings would have not been that visible. What other visual clues would have been available to the pilots that they were sinking too early? the flashing lights at Old Mill Creek?

The JFK charts have a vertical profile section - this does not suggest maintaining altltude past MAP?

 

[jb747]

So they went below minima before MAP (= DMYHL waypoint?) but didnt realise it until told be ATC. Would there have been a "minima" annunciation at some point?

They should not have been below 800’ prior to DMYHL. At that point they have 3.6 miles to run to the threshold, so at 800’ they won’t intercept the vertical path for another mile or so...roughly 25 seconds.

The aircraft would have called minima, and if it didn’t then that’s something for the non flying pilot to do.

The JFK charts have a vertical profile section - this does not suggest maintaining altltude past MAP?

The chart I referenced isn’t the Jeppesen, it was just what I could find on line. The Jepp shows a level segment. Even so, self preservation should push you away from being low on the vertical path. The aircraft shows distance to run (multiply by 3!) and the ‘yo-yo’ on the PFD will show your position relative to a 3º path, even before lined up. Nowhere do you fly 2º paths! This is no different to a visual night circuit, something that is covered on a pilot’s very first night flight.

The approach is the same to either the right or left runway up to the MAP. The right runway is about a mile closer, so management of the vertical path is quite different for right or left. This is the sort of thing that should be covered in the approach briefing.

 

[Quickstatus]

What other major airports are there night VFR approaches like this one?

Are there synthetic visual systems which show the 3 dimensional route a pilot should take?

 

[jb747]

What other major airports are there night VFR approaches like this one?

Who knows? It wasn’t all that long ago that most VOR or NDB approaches would put you into either an offset situation, or dump you into the circuit for a circling approach. The old Hong Kong IGS was offset, as is one of the approaches to Honolulu. This sort of approach is something that is avoided by the authorities if at all possible, but the combination of noise, traffic, and proximate airfields makes it difficult to avoid them entirely. Before I was ever allowed to take an aircraft to JFK, I had to complete a 4 hour sim session that covered these approaches, multiple times.

Are there synthetic visual systems which show the 3 dimensional route a pilot should take?

And perhaps there lies the rub. You can make any FMC simulate one of these approaches, simply by generating a bunch of positions and heights. BUT, you should be able to fly the aircraft without such a system. Literally all you need is to see the runway (and the FMC will be showing an extended centreline anyway) and to be able to multiply by 3. You can’t turn off the generated vertical display, even if you want to. There’s no shortage of cues. This is very basic aviation.

 

[Quickstatus]

“Multiply by 3?”

Do you mean multiply the glideslope distance ( to distance measuring equip?) to the airfield (in miles) by 3 to get the desired altitude (in thousand feet) all the way in?

What is the procedure of ATC wants you to come in at a lower starting altitude?

So EK207 should have been at 200 feet over JFK Hotel (the last set of lead in strobes instead it was 200 feet with about 2.5 miles to go?

What saved the day?. Does ATC have alerting indicators on their displays - say when aircrafts descend past preset minimum descent altitude?

http://archive-server.liveatc.net/kjfk/KJFK-Twr-Dec-05-2017-0100Z.mp3
At -05:40 ATC alerted EK (call sign Emirates 5KP) of extremely low altitude. EK declared missed approach at -05:19 about 20 seconds later. Does this seem a tad delayed - like a deer caught in the headlights?

“Basic aviation”:
Such manual flying (old school?) with instruments surely must be relished by pilots but must require unimpaired cognition especially after a long haul flight across several time zones?

 

[jb747]

That would have been a pilot announcement then and the seat belt signs would be on. They weren’t.

“Multiply by 3?”

Do you mean multiply the glideslope distance ( to distance measuring equip?) to the airfield (in miles) by 3 to get the desired altitude (in thousand feet) all the way in?

A 3º slope is very close to 300’ per nautical mile. There are ways of making all of the aircraft display distance to the threshold. Sometimes that’s where the DME is, though in the USA they tend to put it at the other end of the runways. The 380 will display distance to any spot, including thresholds. So, 3 miles, you should be at about 900’ AGL. Close enough to get you onto the PAPI or VASI.

What is the procedure of ATC wants you to come in at a lower starting altitude?

ATC never ask for a shallower path, and they won’t get it if they do. But you can intercept the glide path at any altitude...simplest way is to just maintain level until you get to it.

So EK207 should have been at 200 feet over JFK Hotel (the last set of lead in strobes instead it was 200 feet with about 2.5 miles to go?

2.5 miles...500’. Pluse whatever the threshold elevation is. JFK is close enough to zero to ignore for this discussion.

What saved the day?. Does ATC have alerting indicators on their displays - say when aircrafts descend past preset minimum descent altitude?

I don’t know. They are the bossiest controllers in the world, so perhaps it was just another chance to put a pilot in his place.

http://archive-server.liveatc.net/kjfk/KJFK-Twr-Dec-05-2017-0100Z.mp3
At -05:40 ATC alerted EK (call sign Emirates 5KP) of extremely low altitude. EK declared missed approach at -05:19 about 20 seconds later. Does this seem a tad delayed - like a deer caught in the headlights?

Perhaps, but just as likely that the call was made well after the G/A was initiated. There are other things to do.

“Basic aviation”:
Such manual flying (old school?) with instruments surely must be relished by pilots but must require unimpaired cognition especially after a long haul flight across several time zones?

Do a search for video “Children of the magenta line”. Airlines are pushing more and more use of automatics. Hiring pilots who only know how to use them, and have minimal flight time in basic aircraft. Flight times are pushing out, which leads to fatigued pilots. So, you end up with someone who is tired, has forgotten or never knew how to fly manually, and an approach that requires old style aviation. Really no different to Asiana in SFO. Couldn’t do a visual approach in daylight.

 

[jb747]

I had a look at this approach in the aircraft last night. It ends in a discontinuity at the MAP, so it is designed to preclude use of automatics beyond that point. That wouldn't stop someone from using the dumber autopilot modes, but would surely act as a huge red flag to most.

 

[Quickstatus]

I had a look at this approach in the aircraft last night. It ends in a discontinuity at the MAP, so it is designed to preclude use of automatics beyond that point. That wouldn't stop someone from using the dumber autopilot modes, but would surely act as a huge red flag to most.

The "magenta line" stops at the MAP?. Would you hazard a guess as to how they got to where they were?

Are there "descent modes" on airbus that could be at play here?
Were they close to stall?

 

[jb747]

The "magenta line" stops at the MAP?.

It's actually a green line in Airbus. I assume Boeing copyrighted magenta.

Discontinuities are common. We sometimes load them into the route ourselves. They'll eventually be removed, but serve as place holders for route building. In this instance it simply means there's no FMC track to follow.

Would you hazard a guess as to how they got to where they were?

Track wise, they're in about the right place. It's the vertical that's at issue. In theory they could have built a couple of waypoints to make the aircraft fly the track, but it's actually easier to just look out the window. But, if you really wanted, you could use heading and v/s modes to make the autopilot fly the aircraft.

Are there "descent modes" on airbus that could be at play here?

They could have selected v/s -700 (or so). You could do the same in any aircraft. That have been the correct sink rate once they'd intercepted the normal 3º path. But, it's not a case of the descent mode being in 'play'. Its an inappropriate use of the automatics.

Were they close to stall?

No. Nowhere near. In any event, the aircraft isn't stallable in normal law. It would not, for instance, allow a repeat of the SFO 777 event. Alpha protection would limit the available angle of a attack, and it would wake up the auto thrust, even if it had been turned off. AF447 wasn't in normal law.

 

[Quickstatus]

Thanks and merry Christmas!

So even in normal law this flight could have ended up in the papers?.

 

[jb747]

So even in normal law this flight could have ended up in the papers?.

The laws are helpful, not the other way around. All FBW aircraft have them.

In normal law, the aircraft will not allow a stall. It will allow you to pull to, and hold, maximum angle of attack, which could save the bacon in a windshear, or ground proximity event. It limits the attitudes that you can select, but the limits are far beyond anything you need in any airliner operation.

Alternate law is a degraded law, which the aircraft will drop into with various system failures. It now basically flies like a non FBW aircraft. It is now possible to stall the aircraft, but it is no less safe in this mode than any 737/757/767 or 747 is normally. Automatic pitch trim is still enabled, and in most cases autopilots are still available.

Direct law is a further degradation, relating mostly to the inputs available to the flight control system. There is no computer modulation of control inputs, and no automatics work.

There are a couple of other variations on the laws, which seamlessly come into play if needed. For instance, during all landings, at about 100' the controls switch to flare law, in which roll and yaw are still in normal law, but pitch is in a modified form of direct law.

 

[Franky]

JB747 - can I say thanks to you for your informative posts this year. I must admit that some of them are beyond my comprehension, but I think I get the gist most of the time. It's good to hear from one of the drivers of these machines, as well the other pilots who also contribute to this thread. I hope you enjoy whatever time off you get over the festive season, and I look forward to more posts from you in the New Year. Regards, Frank.

 

[flychrisfly]

HI Pilots, can you please clarify the use of the terms 'long final' and 'short final'? In various forums I've seen 'short final', for example, to mean 'on approach and close to landing' and 'landing clearance given late by ATC'. Which one of these definitions is used by pilots or is it something else?