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-   -   Good day for GPWS (https://www.airlinepilotforums.com/safety/110739-good-day-gpws.html)

JohnBurke 01-30-2018 02:43 AM


Originally Posted by galaxy flyer (Post 2514943)
FAA ATC is required to assign an altitude with the approach clearance when clearing an aircraft on an unpublished route. See FAAO 7110.65 4-8-1 Approach Clearances. This was very technically legal as the MVA was 7,800 from where the aircraft was located to CEGAN. It was erroneous due to the MVA later on the arc rose to 8,700’. The ATCO would have been better to say, “cross CEGAN at or above 10,000’”.

GF

Given that the aircraft was not provided vectors at this point and ATC would not be providing terrain separation or guidance during the approach, use of the MVA was at best misleading and erroneous, and at worst, very dangerous. The use of MVA in the descent and approach clearance, even if not explicitly stated as MVA, implies that ATC has ratified that as an acceptable altitude. The use of MVA from an ATC perspective also implies a willingness or capability of continuing to provide vectors or direction at that altitude, if given as available, to ensure continued terrain clearance at that altitude.

Unless ATC had every intention of continuing to use MVA throughout the flight progress to the airport in the form of vectors, it shouldn't have been given in the approach clearance.

galaxy flyer 01-30-2018 07:35 AM

John,

I agree and the controller, if using MVA, had, by policy, to have the arc displayed on the video and monitored the flight progress. Certainly, the latter was not done. I’m not arguing the controller was correct, just a very narrow read of .65. Pilots always need to assume terrain clearance responsibility, if only, because they die if they’re wrong.

GF

WhisperJet 01-30-2018 09:02 AM


Originally Posted by Mercyful Fate (Post 2507845)
Is the GPWS something that is always required to be operational for a 121 operated flight?

Part of being PIC is making the call to refuse an aircraft that has an operational MEL if the situation warrants it. If I'm going into mountainous terrain, at night, in the wx, you can be damn sure I'm not going without a GPWS.

Adlerdriver 01-30-2018 01:07 PM


Originally Posted by CBreezy (Post 2514733)
I agree with this. In MANY airports in the US, I've been cleared down to the MVA, then told to cross a fix 1000 feet below its charted altitude restriction. Within radar contact, if ATC clears you to cross a fix at or below a certain altitude, in the US, this assures terrain clearance. While the crew *SHOULD* have done a better job of cross-checking the clearance, it is not their solely their fault. ATC holds the lion's share of the blame in this situation. With as much responsibility as they have placed on our shoulders over the last decade with regards to charted procedures, I'm not surprised this has happened. All the guy had to do was clear them to the IAF and then cleared for the approach. Issuing an altitude is a completely unnecessary piece of information, unless of course he intended them to descend to the bottom altitude at CEGAN.

No. This crew gets no slack. It was a poorly crafted, no-sense clearance and they shouldn't have accepted it or simply complied with the non-precision approach for which they were cleared (since the at or above clearance gave them that latitude).

First of all - anyone in 121 ops receiving a clearance to fly a full, No-PT arc to a vor/dme-C in the mountains needs to have their guard up. I think their eventual choice to get the ILS should have been exercised upon arrival looking at the wind trend.

But, they decided to accept the VOR. Okay, fine. But, when that clearance comes in, how can anyone flying a modern FMS equipped jet not have at least a couple of HUGE question marks over their heads? They're flying a published approach.
:confused: #1 - 7800 MSL isn't even a depicted altitude on the approach.
:confused: #2 - Why would ATC give a clearance that may require us to climb after we've already descended (I say "may" because they did have the option to stay at or above 10K)

This stuff about some RJ drivers being instinctively prone to comply and ask questions later is nonsense. Little boys worrying about making ATC mad need to grow up, put their big boy pants on and figure it out.

We input the approach in the box, check the points/altitudes and brief, with someone cross-checking the box with the plate. At some point, you would think they had to at least discuss the fact that the lowest altitude on the arc from CEGAN to BRKET was 10,000. So, they either comply with their clearance but stay at/above 10K until starting the lead turn off the arc, realizing that ATC set them up or they CLARIFY.

But, since neither of those two options were exercised, it seems pretty clear that these two guys were grossly unfamiliar with the approach they just accepted a clearance to fly. I obviously can't say for sure, but it seems like a reasonably conclusion that they didn't brief and didn't cross-check FMS inputs. If they did either of these two things, I find it hard to understand how they got to the point of a GPWS alert.

All that said, this ATC controller was an idiot. Someone needs to educate him on the huge difference between legal and smart. Combining an unrelated MVA with a clearance to begin a full-up instrument procedure from a distant IAF may be legal (don't know for sure) but it's certainly not a good practice. We get tested enough on a daily basis from threats we can't control or minimize. We don't need ATC throwing out random Easter eggs because they're too lazy to use an appropriate altitude for a VOR clearance instead of just grabbing the MVA off their screen.

galaxy flyer 01-30-2018 05:23 PM

Adlerdriver,

Then again, I’ve seen pilots, 250nm from the destination, act as if the descent clearance is a command and never ask, “do we need start now” or “can we make that, ‘when ready, descend’”.

GF

JohnBurke 01-30-2018 06:40 PM


Originally Posted by galaxy flyer (Post 2515344)
John,

I agree and the controller, if using MVA, had, by policy, to have the arc displayed on the video and monitored the flight progress. Certainly, the latter was not done. I’m not arguing the controller was correct, just a very narrow read of .65. Pilots always need to assume terrain clearance responsibility, if only, because they die if they’re wrong.

GF

Quite so.

At the end of the day, the controller goes home to sleep in his own bed. This is not always true of the crew and contents.

CBreezy 01-31-2018 09:17 AM


Originally Posted by Adlerdriver (Post 2515635)
No. This crew gets no slack. It was a poorly crafted, no-sense clearance and they shouldn't have accepted it or simply complied with the non-precision approach for which they were cleared (since the at or above clearance gave them that latitude).

First of all - anyone in 121 ops receiving a clearance to fly a full, No-PT arc to a vor/dme-C in the mountains needs to have their guard up. I think their eventual choice to get the ILS should have been exercised upon arrival looking at the wind trend.

But, they decided to accept the VOR. Okay, fine. But, when that clearance comes in, how can anyone flying a modern FMS equipped jet not have at least a couple of HUGE question marks over their heads? They're flying a published approach.
:confused: #1 - 7800 MSL isn't even a depicted altitude on the approach.
:confused: #2 - Why would ATC give a clearance that may require us to climb after we've already descended (I say "may" because they did have the option to stay at or above 10K)

This stuff about some RJ drivers being instinctively prone to comply and ask questions later is nonsense. Little boys worrying about making ATC mad need to grow up, put their big boy pants on and figure it out.

We input the approach in the box, check the points/altitudes and brief, with someone cross-checking the box with the plate. At some point, you would think they had to at least discuss the fact that the lowest altitude on the arc from CEGAN to BRKET was 10,000. So, they either comply with their clearance but stay at/above 10K until starting the lead turn off the arc, realizing that ATC set them up or they CLARIFY.

But, since neither of those two options were exercised, it seems pretty clear that these two guys were grossly unfamiliar with the approach they just accepted a clearance to fly. I obviously can't say for sure, but it seems like a reasonably conclusion that they didn't brief and didn't cross-check FMS inputs. If they did either of these two things, I find it hard to understand how they got to the point of a GPWS alert.

All that said, this ATC controller was an idiot. Someone needs to educate him on the huge difference between legal and smart. Combining an unrelated MVA with a clearance to begin a full-up instrument procedure from a distant IAF may be legal (don't know for sure) but it's certainly not a good practice. We get tested enough on a daily basis from threats we can't control or minimize. We don't need ATC throwing out random Easter eggs because they're too lazy to use an appropriate altitude for a VOR clearance instead of just grabbing the MVA off their screen.

I'm not saying I'm giving the crew slack. I said they should have known better. I'm just saying the mistake isn't SOLELY their fault. I am just as frustrated as anyone else here who watches their FO or CA dive for the AT in a At or above clearance instead of using FMS VNAV or staying level and grabbing the GS and following it down. I have found even the most experienced captains have some of the worst instrument procedure knowledge. Yes, they should have never descended below 10,000 as depicted in the arc. If they weren't comfortable flying the arc or it had been awhile since flying one, they should have requested the ILS. Unable is a beautiful creature and we need to use it more as pilots. Too often, lazy controllers do what is best for them and not always what is safest for the aircraft.

And like I said before, one of the biggest problems is that we so often get vectors for the approach, a lot of pilots get confused (their fault) on vectoring for a final and full approach procedures. We are so used to getting clearances to descend below platform altitudes that most don't even flinch anymore...like driving it in at 4000 feet over Lake Michigan to O'Hare or being 20 miles out of ATL and getting 3000 feet (not depicted on any platform).

Adlerdriver 01-31-2018 09:46 AM


Originally Posted by CBreezy (Post 2516343)
I'm not saying I'm giving the crew slack. I said they should have known better. I'm just saying the mistake isn't SOLELY their fault.

I understand what you're saying and I respectfully disagree. They knew they were flying a full-up IAP. ATC can't override published altitude restrictions in that situation. What they chose to do did not comply with the IAP they were cleared to fly. That's 100% their responsibility. It's that simple.

If ATC had vectored them into a GPWS alert trying to get them onto a portion of the approach down track, then I would agree the blame should be shared.

The only reason I even threw a single spear in the direction of ATC was because he actually came back and defended the dumba$$ clearance he gave them. If he had acknowledged the altitude limit he provided made no sense and it was a mistake, I'd have nothing to say about him (other than it was a human error that caused confusion).

But we get confused by ATC regularly. We do the same to them. That's why we use the feedback loop and clarify as necessary. The one nice thing about being cleared to proceed direct to an IAF and cleared for the VOR/DME-C is that the communication is done. The restrictions, routings and mins are all there in black and white with no requirement for further communication until we switch to tower. This was a procedural error on the part of this crew who somehow arrived at that point in their career with the mistaken impression that ATC could lower a depicted IAP altitude restriction over VHF. The error is all theirs, IMO.

WesternSkies 01-31-2018 02:43 PM

I can understand how this happened better than I can understand your position.

Adlerdriver 01-31-2018 04:18 PM


Originally Posted by WesternSkies (Post 2516614)
I can understand how this happened better than I can understand your position.

Okay, fair enough. I'm either off base, not making my point well or a little of both.

Sure, I can understand how this happened too. It appears that ATC instructions were perceived as the gospel even though they directly contradicted the printed information on the IAP the crew was cleared to fly.

So, these two pilots either believed ATC could clear them to start an IAP from the IAF at an altitude lower than published...or

They were unaware of the published minimum altitude on the arc.

Both of those situations are unacceptable in my opinion and point to a perception and/or procedural failure on the crew's part.

It would appear the problem is assuming ATC is infallible and blindly following their instructions in the face of very specific and clear published guidance to the contrary. That's my point.

Would you blame ATC or say they at least shared the blame if ground cleared someone to taxi across the grass to get to the gate and they complied? Some things are simply black and white and the pilots are the final quality check.


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