UA169 (VCE-EWR), aircraft or parts of it hit truck on I-95

[mwflyer]

Since we are talking about it. Keep an eye out of the note "Glidepath and VGSI not coincident" or something like that. I can't remember if it was on the ILS or RNAV into 14L at BFI, but there used to be a note like that on the chart. I don't see it anymore. I remember following the glidepath on a visual and the FO says "Red over red", which was a callout. Nobody ever said it except this one F/O. Damned if he wasn't right. I was on glidepath on the FD but if you look out the window at VGSI, I was low. The note means any time below minimums, you gotta be looking at the VASI or PAPI and not electronic glidepath.

I’ve seen that note on an approach as well. It wasn’t at BFI, but I’ve seen it.

 

[DropTank]

There’s still commercial turbojets flying?

Ever landed one on a 3800 ft runway? Sometimes it’s required.

If you're landing a turbojet on a short runway, and you're required to dip, you're either on a secret mission, or begging for an overrun.

No alternate nearby? No Uber, rental car, limo service available?

At those distances, you're one unreported contanimation, one gust of wind, one blown tire, one emergency, or one mistake away from the grass, or trees, or elementary school, or 1000' of cliff.

Do it once, primaries expect it every time. No exceptions.

Change the destination, change the timing, mitigate SOMETHING

Most over runs are preceded by "yeah, we always do that!"

Cool... that Glide Slope antenna costs $200,000.

Credit card or cash?

Also.... start printing a new resume

(but what do I know?)

 

[DE727UPS]

Glideslope antenna? It's off to the side 1000 feet down the runway. Now the Localizer antenna. You hit that and you really got problems....

 

[DropTank]

Glideslope antenna? It's off to the side 1000 feet down the runway. Now the Localizer antenna. You hit that and you really got problems....

It's on the opposite end, usually within 300' of the centerline.

Yeah yeah, shoulda said LOC antenna and pretty lights.

(and bread trucks)

 

[luke3]

Since we are talking about it. Keep an eye out of the note "Glidepath and VGSI not coincident" or something like that. I can't remember if it was on the ILS or RNAV into 14L at BFI, but there used to be a note like that on the chart. I don't see it anymore. I remember following the glidepath on a visual and the FO says "Red over red", which was a callout. Nobody ever said it except this one F/O. Damned if he wasn't right. I was on glidepath on the FD but if you look out the window at VGSI, I was low. The note means any time below minimums, you gotta be looking at the VASI or PAPI and not electronic glidepath.

Nerd out time!

Let me put my airport compatibility engineer hat on for a minute, since this incident made me go dig up some old manuals from a previous career. That note, and the TCH in general, can be very sneaky. The FAA has a Joint Order (6850.2B if you're curious) that specifies the minimum TCH for the PAPI approach path based on the eye-to-wheel height category of the aircraft, with applicable tolerances.

What this means practically is if you're flying a widebody or a 757 and see a TCH or a "VGSI not Coincident. VGSI TCH" of 59ft or less, your spidey senses should be going off, because you have much less margin than you think you do. In fact it's a giveaway that the approach is designed for small narrowbodies as the critical aircraft, so your operation is an outlier. At 50ft TCH on a 757/767 you'd only have 20ft of wheel clearance on path, and only 18ft on a 767-400.

On 29 in EWR it's right at 60ft, the lower limit for widebody operations. The -400 has 28ft of clearance on two reds and two whites.

Internationally it's a bit more tricky to calculate because in ICAO land, the Annex 14 recommendation is in terms of wheel clearance margin instead of TCH

But if we do the math backwards it ends up recommending the upper tolerance of the FAA brackets. So on my 757 it ends up being the same: 59ft TCH or less and I pay a lot closer attention.

 

[jtrain609]

Nerd out time!

Let me put my airport compatibility engineer hat on for a minute, since this incident made me go dig up some old manuals from a previous career. That note, and the TCH in general, can be very sneaky. The FAA has a Joint Order (6850.2B if you're curious) that specifies the minimum TCH for the PAPI approach path based on the eye-to-wheel height category of the aircraft, with applicable tolerances.
View attachment 89580
What this means practically is if you're flying a widebody or a 757 and see a TCH or a "VGSI not Coincident. VGSI TCH" of 59ft or less, your spidey senses should be going off, because you have much less margin than you think you do. In fact it's a giveaway that the approach is designed for small narrowbodies as the critical aircraft, so your operation is an outlier. At 50ft TCH on a 757/767 you'd only have 20ft of wheel clearance on path, and only 18ft on a 767-400.

On 29 in EWR it's right at 60ft, the lower limit for widebody operations. The -400 has 28ft of clearance on two reds and two whites.

Internationally it's a bit more tricky to calculate because in ICAO land, the Annex 14 recommendation is in terms of wheel clearance margin instead of TCH
View attachment 89581

But if we do the math backwards it ends up recommending the upper tolerance of the FAA brackets. So on my 757 it ends up being the same: 59ft TCH or less and I pay a lot closer attention.

Help me out here.

On my aircraft (A320/321), the internets say that the RA is calibrated to read the altitude based on the wheel height. I haven't dug the FCOM II out, but this seems to check.

So when I cross the threshold with two red and two white on a visual, and I hear the aircraft call out 50, my wheels are 50' above the threshold, not 20 feet above the threshold.

I've always used that for my cross check to verify that I'm where I'm supposed to be.

So...help me out here, because I'm clearly missing something.

 

[luke3]

Help me out here.

On my aircraft (A320/321), the internets say that the RA is calibrated to read the altitude based on the wheel height. I haven't dug the FCOM II out, but this seems to check.

So when I cross the threshold with two red and two white on a visual, and I hear the aircraft call out 50, my wheels are 50' above the threshold, not 20 feet above the threshold.

I've always used that for my cross check to verify that I'm where I'm supposed to be.

So...help me out here, because I'm clearly missing something.

Off the top of my head I think almost all GPWS systems have Mode 6 callouts based on the gear. At least on my fleet lot of people still do the "6...4...2...0" callouts in the flare and it seems to match.

It's been a few years since I've flown "Le Bus" so unfortunately I don't have the manuals for it anymore. There's a little chart my company put out buried in one of the fleet bulletin articles that has a summary of eye-to-wheel height for all our types. Ever since we took that 330 off roading in AMS there's been a push to have more awareness of the subject. Based on that I'm seeing an EWH of 23ft for the 320/321. Most larger airports you're going into have the PAPI calibrated for Height Group 4 per my chart above, so TCH of 75ft +5 / -15. On a typical installation your wheels will cross at 52ft, which tracks with your observation. With the tolerance applied you could be anywhere from 57 to 37. I'm guessing for you to register a difference in the GPWS callout and cadence you'd need to have 45ft or less, which would be a charted VGSI TCH of 68ft or less.

It starts to be more of a problem on widebodies. That same chart shows an EWH of 30ft for the 757/767-300, 32ft for the 767-400, 36ft for all A330s and 38ft for the A350-900

 

[BobDDuck]

Off the top of my head I think almost all GPWS systems have Mode 6 callouts based on the gear. At least on my fleet lot of people still do the "6...4...2...0" callouts in the flare and it seems to match.

It's been a few years since I've flown "Le Bus" so unfortunately I don't have the manuals for it anymore. There's a little chart my company put out buried in one of the fleet bulletin articles that has a summary of eye-to-wheel height for all our types. Ever since we took that 330 off roading in AMS there's been a push to have more awareness of the subject. Based on that I'm seeing an EWH of 23ft for the 320/321. Most larger airports you're going into have the PAPI calibrated for Height Group 4 per my chart above, so TCH of 75ft +5 / -15. On a typical installation your wheels will cross at 52ft, which tracks with your observation. With the tolerance applied you could be anywhere from 57 to 37. I'm guessing for you to register a difference in the GPWS callout and cadence you'd need to have 45ft or less, which would be a charted VGSI TCH of 68ft or less.

It starts to be more of a problem on widebodies. That same chart shows an EWH of 30ft for the 757/767-300, 32ft for the 767-400, 36ft for all A330s and 38ft for the A350-900

I've never paid a ton of attention, but I feel like the 50 foot call on the 330 occurs prior to the cockpit crossing the threshold.

 

[Roger Roger]

the 50 foot call

The AS guppy mind cannot comprehend

 

[GypsyPilot]

And yet done so frequently without a single thought to the 100+ feet of aircraft hanging out behind the cockpit. I just had an FO do it to me yesterday despite me telling him not to when he briefed he was going to.

Man that •s crazy. I wouldn’t do that in a CRJ going into BUR or SNA. Doing that in a heavy…. WTAF.

 

[GypsyPilot]

There’s still commercial turbojets flying?

Ever landed one on a 3800 ft runway? Sometimes it’s required.

I have, at TPF and VLL in a CJ3. We did it very frequently at VLL, and you could hit power lines and/or trees if you didn’t follow the PAPI (3.75°).

There’s never a valid reason for going below the glidepath. If you have calculated the performance, then just fly it like you’re supposed to.

 

[derg]

Intentionally dipping below the VASI/PAPI is a deadhead back to base at my employer.

Otherwise, “normalization of deviance”.

 

[Cherokee_Cruiser]

Now whenever an FO pulls that shtick I ask them where in our manuals it tells us that it’s acceptable to intentionally fly below the glide path/VGSI on short final.

What about cases where ILS and VGSI are not coincident, VGSI height is 70+ ft at threshold?

 

[GypsyPilot]

Nerd out time!

Let me put my airport compatibility engineer hat on for a minute, since this incident made me go dig up some old manuals from a previous career. That note, and the TCH in general, can be very sneaky. The FAA has a Joint Order (6850.2B if you're curious) that specifies the minimum TCH for the PAPI approach path based on the eye-to-wheel height category of the aircraft, with applicable tolerances.
View attachment 89580
What this means practically is if you're flying a widebody or a 757 and see a TCH or a "VGSI not Coincident. VGSI TCH" of 59ft or less, your spidey senses should be going off, because you have much less margin than you think you do. In fact it's a giveaway that the approach is designed for small narrowbodies as the critical aircraft, so your operation is an outlier. At 50ft TCH on a 757/767 you'd only have 20ft of wheel clearance on path, and only 18ft on a 767-400.

On 29 in EWR it's right at 60ft, the lower limit for widebody operations. The -400 has 28ft of clearance on two reds and two whites.

Internationally it's a bit more tricky to calculate because in ICAO land, the Annex 14 recommendation is in terms of wheel clearance margin instead of TCH
View attachment 89581

But if we do the math backwards it ends up recommending the upper tolerance of the FAA brackets. So on my 757 it ends up being the same: 59ft TCH or less and I pay a lot closer attention.

Can you walk me through this math? I fly a 767-300 into CRK quite often, and the TCH is 50’ for this approach with a 3.5° glidepath:

Cockpit to ground height is 18’ 2”:

Of course, the main gear is behind us and angled at 2.2° on a 3° glidepath. So according to this table, main gear height is 29 feet and pilot eye height is 53 feet:

Pilot eye height (53 feet) - main gear height (29 feet) = 24 feet.

So for a given TCH on a 3° glidepath, can I just subtract 24 feet to get the main gear height crossing the threshold? If so, why is this number different than yours (20 ft)?

What about for this CRK approach with a 3.5° glidepath?

 

[pwttogfk]

There’s still commercial turbojets flying?

Ever landed one on a 3800 ft runway? Sometimes it’s required.

This is an example of why 91 can fly better equipment with better training and still have worse accident stats. Our FOM requires a 50% margin over preflight calculated field length. The company’s bought off on it, and we don’t have any drama. Are there airports we probably could go to that we don’t? Yup. Do we have to deviate from how you train to fly a transport category jet to get the job done? Nope.

 

[Karnage]

Intentionally dipping below the VASI/PAPI is a deadhead back to base at my employer.

Otherwise, “normalization of deviance”.

Either come to the Guppy or help me with my LCP application next time it comes up so I can make this a thing (and also so I can torment @Autothrust Blue with extra line checks, mostly this).

 

[luke3]

Can you walk me through this math? I fly a 767-300 into CRK quite often, and the TCH is 50’ for this approach with a 3.5° glidepath:

Pilot eye height (53 feet) - main gear height (29 feet) = 24 feet.

So for a given TCH on a 3° glidepath, can I just subtract 24 feet to get the main gear height crossing the threshold? If so, why is this number different than yours (20 ft)?

What about for this CRK approach with a 3.5° glidepath?

Your calculations are correct.

In my original example I used the numbers from a table that popped up in on of our 350 fleet newsletters from an article that addressed this issue. I used that because it had all the aircraft in our fleet and was the only place I could easily find the -400 numbers to help me frame this incident, and quickly compare with other aircraft. When I use the numbers from the 767 FCTM it matches your results. The newsletter didn't say what assumptions they used in that table so I'm not sure where the difference comes from. Maybe they're just padded for conservativism. I'd like to see the data for Flaps 25 but unfortunately I couldn't find it in the FCTM anywhere. That could be where the discrepancy comes from since it comes in a bit more nose high in that configuration.

As for the 3.5 degree glideslope, from the FCTM chart of the ILS landing geometry the relationship does not change between 2.5 and 3 degrees. Your body attitude will be slightly lower as well with the steeper glidepath, by a very small amount and be negligible, just like it basically is from 3 to 2.5. There's a chart further down in the FCTM under the Landing section showing the geometry for a 3-bar VASI at 3.25 degrees. Ignoring the crossing heights which are different, when you subtract the pilot eye height and main gear height, you get the same number as on the ILS charts. The body attitude is 2.0 degrees.

 

[GypsyPilot]

Your calculations are correct.

In my original example I used the numbers from a table that popped up in on of our 350 fleet newsletters from an article that addressed this issue. I used that because it had all the aircraft in our fleet and was the only place I could easily find the -400 numbers to help me frame this incident, and quickly compare with other aircraft. When I use the numbers from the 767 FCTM it matches your results. The newsletter didn't say what assumptions they used in that table so I'm not sure where the difference comes from. Maybe they're just padded for conservativism. I'd like to see the data for Flaps 25 but unfortunately I couldn't find it in the FCTM anywhere. That could be where the discrepancy comes from since it comes in a bit more nose high in that configuration.

As for the 3.5 degree glideslope, from the FCTM chart of the ILS landing geometry the relationship does not change between 2.5 and 3 degrees. Your body attitude will be slightly lower as well with the steeper glidepath, by a very small amount and be negligible, just like it basically is from 3 to 2.5. There's a chart further down in the FCTM under the Landing section showing the geometry for a 3-bar VASI at 3.25 degrees. Ignoring the crossing heights which are different, when you subtract the pilot eye height and main gear height, you get the same number as on the ILS charts. The body attitude is 2.0 degrees.

Awesome, thanks for sparking this discussion! This is something I’m going to pay a lot more attention to now, and include in briefs as appropriate.

 

[KLB]

Nerd out time!

Let me put my airport compatibility engineer hat on for a minute, since this incident made me go dig up some old manuals from a previous career. That note, and the TCH in general, can be very sneaky. The FAA has a Joint Order (6850.2B if you're curious) that specifies the minimum TCH for the PAPI approach path based on the eye-to-wheel height category of the aircraft, with applicable tolerances.
View attachment 89580
What this means practically is if you're flying a widebody or a 757 and see a TCH or a "VGSI not Coincident. VGSI TCH" of 59ft or less, your spidey senses should be going off, because you have much less margin than you think you do. In fact it's a giveaway that the approach is designed for small narrowbodies as the critical aircraft, so your operation is an outlier. At 50ft TCH on a 757/767 you'd only have 20ft of wheel clearance on path, and only 18ft on a 767-400.

On 29 in EWR it's right at 60ft, the lower limit for widebody operations. The -400 has 28ft of clearance on two reds and two whites.

Internationally it's a bit more tricky to calculate because in ICAO land, the Annex 14 recommendation is in terms of wheel clearance margin instead of TCH
View attachment 89581

But if we do the math backwards it ends up recommending the upper tolerance of the FAA brackets. So on my 757 it ends up being the same: 59ft TCH or less and I pay a lot closer attention.

So with this info...it doesn't necessarily have to be a scenario where the crew intentionally ducked under. It just could have been that they were just slightly low of the path from a visual standpoint.

If you take a good look at that runway...there is a heck of a lot of rubber left behind between the numbers and the touchdown markers also. So it seems to be quite normal that planes were landing prior to the touchdown zone.

 

[MikeD]

Should be an easy one to determine the how and why, with the CVR/FDR info available, and to flight check the PAPI to ensure it’s adjusted correctly.