Drift Down Routes

[Cardinal]

Unfortunately for me, our FOM does not provide as much discretion. We are able to deviate from the route as long as its within 5 miles either side of the route.

I just looked at my old one, and it says the same things, specifically allows for deviations in an emergency. However the operating philosophy described above was how we taught the matter, and how we demonstrated it to the Feds I had on aircraft on a weekly basis. Would your POI be more impressed with reasonable judgement or getting into a pissing match with ATC on the frequency?

The guy even told me that I'm required to accept his clearance because that is regulation and it supersedes my terrain clearance regulation

He is probably right. I perused 7110.65 and 121.191 but can't offer evidence for the assertion.

Another thought experiment: Any driftdown plan, using .191(a)1 or .191(a)2 makes a number of assumptions, many are bunk. A key assumption is the climb profile. Your planning software - necessary to comply with (a)2 - in all likelihood uses a best angle, uninterrupted climb from the runway to your planned cruise level. That never happens, and we all know it. So the data we're working from is invalid and doesn't comply with 121.191 the second we're held at an intermediate level. Are you crosschecking ISA deviation in the climb? One more way your data is in error and compliance is in question from the beginning.

The reg is a good one, it ensures you have options should an engine fail at an innoportune time, Fate Is The Hunter style. But take the broad view, comply with the letter of the law to the extent possible, then consider the spirit and principles behind it. Although I imagine I'm wasting my breath.

Further, what are we actually going to do when the dreaded engine failure occurs? We had a leg from FMN-DEN, passed directly over ALS, which lies in an huge 80 mile wide valley, hemmed in on both sides by 14000' mountains. Most days the computer showed (a)2 compliance with no alternates, thus if an engine failure happened directly over ALS, one could make it over the intervening mountain range and stagger to DEN. So, given an engine failure on a VMC day over ALS, are we going to land at the near and suitable airport below us, or buzz the hikers for 170 miles to our "driftdown approved" destination? I know what I'd do.

Know the regs. Know that they are in conflict. Apply reasonableness.

 

[Cardinal]

Descent is another area where compliance is unlikely. Larks Arrival into DEN, turboprops get cleared down to 16,000, which is basically the MVA, and are held down there for 30 miles until buzzing a ridgeline with a little more than 2,000 clearance. The paperwork says continue to the destination, but if you had a worst case engine failure plus a little ice, then stayed on the approved route, you'd end up a splatter on the side of the mountain. Reality is not considered.

 

[Nevets]

I just looked at my old one, and it says the same things, specifically allows for deviations in an emergency. However the operating philosophy described above was how we taught the matter, and how we demonstrated it to the Feds I had on aircraft on a weekly basis. Would your POI be more impressed with reasonable judgement or getting into a pissing match with ATC on the frequency?

I don't want to impress anyone. I rather follow regulations and the company FOM.

He is probably right. I perused 7110.65 and 121.191 but can't offer evidence for the assertion.

Well, he cannot compel me to accept any clearance. He was not correct in that assertion.

Another thought experiment: Any driftdown plan, using .191(a)1 or .191(a)2 makes a number of assumptions, many are bunk. A key assumption is the climb profile. Your planning software - necessary to comply with (a)2 - in all likelihood uses a best angle, uninterrupted climb from the runway to your planned cruise level. That never happens, and we all know it. So the data we're working from is invalid and doesn't comply with 121.191 the second we're held at an intermediate level. Are you crosschecking ISA deviation in the climb? One more way your data is in error and compliance is in question from the beginning.

The reg is a good one, it ensures you have options should an engine fail at an innoportune time, Fate Is The Hunter style. But take the broad view, comply with the letter of the law to the extent possible, then consider the spirit and principles behind it. Although I imagine I'm wasting my breath.

Further, what are we actually going to do when the dreaded engine failure occurs? We had a leg from FMN-DEN, passed directly over ALS, which lies in an huge 80 mile wide valley, hemmed in on both sides by 14000' mountains. Most days the computer showed (a)2 compliance with no alternates, thus if an engine failure happened directly over ALS, one could make it over the intervening mountain range and stagger to DEN. So, given an engine failure on a VMC day over ALS, are we going to land at the near and suitable airport below us, or buzz the hikers for 170 miles to our "driftdown approved" destination? I know what I'd do.

Know the regs. Know that they are in conflict. Apply reasonableness.

First, this happened more than 500 NM after our departure airport. It had nothing to do with the climb profile. Which is also why crosschecking ISA deviation during the climb 500 NM ago doesn't apply. Plus, our FOM does not give discretion on using ISA deviations or anti-ice application other than what is on the release. After these situations, I believe my company is going to amend our FOM to give us more discretion to mitigate these situations in the future.

Second, if there is an engine failure, our release tells us what alternates to proceed to and what route to use to get there. We may have multiple alternates depending on where the engine failure occurs. It assures 2000 feet clearance to drift down to those alternates.

I think I know the regs and our FOM. I offered reasonable suggestions to the controller. He was not willing to apply reasonableness to the situation, IMHO.

 

[Nevets]

Descent is another area where compliance is unlikely. Larks Arrival into DEN, turboprops get cleared down to 16,000, which is basically the MVA, and are held down there for 30 miles until buzzing a ridgeline with a little more than 2,000 clearance. The paperwork says continue to the destination, but if you had a worst case engine failure plus a little ice, then stayed on the approved route, you'd end up a splatter on the side of the mountain. Reality is not considered.

Our drift down routes don't always start at the departure airport or end at the destination airport. They are usually between two or more points along our flight.

Look, I didn't post here to argue when to follow or not follow regulations or company procedures. Obviously, there is a time and place where you throw those things out. What I wanted to know is if controllers out west actually know about this or was this just a couple of isolated instances in a particular ATC facility. Controller input would be welcomed.

 

[gt1900]

Just curious.... What would you do if WX was covering the entire airway and ATC tried to vector you around it? Would you turn it down and fly through it because of driftdown? What if ATC had to send other A/C into your airspace because of WX and they needed to send you more than 5 miles off your route to clear them? Would you say no and send the other a/c into a thunderstorm?? Because ive seen tons of stuff like that happen out west. It sounds like your FOM is very vague and doesn't cover every situation, and thats not your fault. You don't know why ATC was trying to move you, but based off of how mad the controller got, I'm guessing there could have been something going on more important than your driftdown. But then again, maybe not. The controller could have just been a jerk.. My point is that we as pilots don't always know why ATC does the things they do. But I have several friends who are controllers and trust me, pilots may think they know everything, but we don't. Especially when it comes to ATC.. Who knows, maybe your company filed a route that conflicted with other traffic flow. Maybe ATC didn't catch it until you were already airborne..... Get it. Sometimes its better to just move.

 

[Nevets]

Just curious.... What would you do if WX was covering the entire airway and ATC tried to vector you around it? Would you turn it down and fly through it because of driftdown? What if ATC had to send other A/C into your airspace because of WX and they needed to send you more than 5 miles off your route to clear them? Would you say no and send the other a/c into a thunderstorm?? Because ive seen tons of stuff like that happen out west. It sounds like your FOM is very vague and doesn't cover every situation, and thats not your fault. You don't know why ATC was trying to move you, but based off of how mad the controller got, I'm guessing there could have been something going on more important than your driftdown. But then again, maybe not. The controller could have just been a jerk.. My point is that we as pilots don't always know why ATC does the things they do. But I have several friends who are controllers and trust me, pilots may think they know everything, but we don't. Especially when it comes to ATC.. Who knows, maybe your company filed a route that conflicted with other traffic flow. Maybe ATC didn't catch it until you were already airborne..... Get it. Sometimes its better to just move.

Look, we can go through hypotheticals all day long. I've already said that I wouldn't not fly through any thunderstorm. My responsibility does not extend into other aircraft or whatever ATC feels is more important. The controller explained to me his situation and I explained to him mine. He was able to deal with it but not in the way he wanted.

I don't believe the FOM is vague at all. It does not provide guidance to use a different ISA or anti-ice off/on than what is on the release. I believe this will probably be amended but I don't really know. Also, the route is the same one we fly everyday. What changes is the weight, temperature and the use of anti ice. Most times its not an issue.

I have many friends that are center controllers. But they are all from the same facility. The same facility in question. Apperantly this specific facility has had only a couple of controllers deal with this kind of situation. I was just trying to find out if this is also true for other facilities.


It may be better for ATC to just move, but I will follow regulations and company policy as much as possible and not let ATC bully me into anything that I'm not comfortable with. If that means that I or the GV has to wait on the ground another five minutes, so be it. Get it?

 

[gt1900]

My responsibility does not extend into other aircraft or whatever ATC feels is more important

Dude... Not sure where you fly, but in the USA, yes it does. Unless you don't like your pilots license. If you interfere with ATC working an emergency A/C your going to have some serious explaining to do. Same thing for A/C deviating for WX that may enter your flight path. If ATC tells you to move, and you don't, your going to have a short airline career..

 

[Nevets]

My responsibility does not extend into other aircraft or whatever ATC feels is more important

Dude... Not sure where you fly, but in the USA, yes it does. Unless you don't like your pilots license. If you interfere with ATC working an emergency A/C your going to have some serious explaining to do. Same thing for A/C deviating for WX that may enter your flight path. If ATC tells you to move, and you don't, your going to have a short airline career..

Again, you are talking about hypotheticals. There was neither weather deviations or emergency aircraft. The controller stated he had to hold two aircraft on the ground because I was not able to accept the reroute.

Again, no controller can compel any pilot to accept a clearance which violates regulations or company policies. I did my explaining as professionally and concise I could on the frequency and then again on the ground when I called the facility. I further explained it through ASAP/ASRS and the CPO and Standards department. Both of which stand behind me. Anyways, leave the worrying about me career up to me, than you.

This was not the point of this thread. As I previously stated, I'm wondering if this is a situation that controllers at other facilities have had to deal with it and how so?

 

[ATCT]

The only times ive dealt with drift down routing was regarding a re-route for an aircraft flying IAH-SLC (E45X) and they couldnt accept the route I was trying to give. (They couldnt go their filed route due to center restrictions)...so long story short they waited on the ground for abour 2 hours and when center opened up their route, off the went. The pilot was nice enough to explain this to me (when I was working on Flight Data, aka the "other" clearance frequency) because none of us upstairs knew what that was. (nor anyone at ZHU...not much drift down routes in south eastern texas )

ATCT

 

[N1VIBS]

Yeah, that's what I said, among other things. I also suggested that I could climb or descend but the controller was having none of it. He even threatened me with a pilot deviation if I didn't accept his clearance! Another controller asked me if I was declaring an emergency and asked me to squawk 7700! Oh well, I guess I will have to try to educate them one at a time.

I respect the controllers, but never,never let a controller "fly" your aircraft for you!!!

 

[Hold West]

Again, no controller can compel any pilot to accept a clearance which violates regulations or company policies. I did my explaining as professionally and concise I could on the frequency and then again on the ground when I called the facility. I further explained it through ASAP/ASRS and the CPO and Standards department. Both of which stand behind me.

I've never had to deal with this situation, doesn't arise at Honolulu or when I worked in Minneapolis Center.

But I think you handled it exactly correctly, if that means anything. Flow control and aircraft on the ground don't even come close to overriding your responsibilities as PIC. Good job, I say.

 

[dispatchguy]

PICs have the FINAL word on accepting, or refusing any ATC clearance, per 91.3

Sounds like u did everything correctly. If an ATCer offers a clearance that, for whatever reason you cant accept, then you have to tell them that you cant do it.

I remember once jumpseating in DEN Center, and this DEN controller was offering a reroute to an NWA crew that they couldnt accept due to mountain wave activity; well offering is the wrong word, it was more like shove it down their throat. From what I was making out, the NWA crew was trying to explain, very respectfully, that their company restrictions prevented them doing what the controller wanted (fly through a red mountain wave with known severe turb); unfortunately we had to change freq before I heard the resolution. The DEN controller was threatening all sorts of stuff, when the captain got on the radio asking if what the controller'll do if they get hit with some severe turbulence.

 

[Nevets]

Just thought I would update everyone, if you even care. I talked to the ERC. They said I did everything right. There was no pilot deviation. The facility will issue a letter of correction to all their controllers telling them about terrain clearance/drift down regulations and that certain airlines may not be able to accept reroutes due to aircraft limitations. And the specific controller was in "hot water" for being "belligerent" on the frequency.