Mea Gap?

[MikeSF340]

What is an "MEA GAP?" I know I have heard the term, but I have no idea what it is. Any help would be appreciated.

Thanks!

 

[Andy Neill]

http://www.flightsimaviation.com/aviation_theory_17_Enroute_Charts.html

At this website, you will read that an MEA gap exists when you cannot receive the necessary navaids for the airway at the MEA. In other words, although the MEA will guarantee you terrain and obstacle clearance, it will not guarantee navigation capability.

 

[minitour]

...wouldn't that make it a MOCA?

-mini

 

[Andy Neill]

No, a MOCA guarantees you terrain and NAVAID but only within 22 miles of the faicility.

....or to say it better, a MOCA may be involved when there is an MEA gap, but an MEA gap is NOT a MOCA.

 

[minitour]

No, a MOCA guarantees you terrain and NAVAID but only within 22 miles of the faicility.

....or to say it better, a MOCA may be involved when there is an MEA gap, but an MEA gap is NOT a MOCA.

Okay...I think you said what I was thinking in your second sentence...

like...if I'm 36 nm away from a NAVAID then the MEA gap would be the/a MOCA...but if I'm 21 nm away from a NAVAID the MEA gap would be just an MEA gap....

...I guess I never considered an MEA gap close to a navaid....thanks for clearin that up!

-mini

 

[Andy Neill]

like...if I'm 36 nm away from a NAVAID then the MEA gap would be the/a MOCA...but if I'm 21 nm away from a NAVAID the MEA gap would be just an MEA gap....

-mini

I wouldn't say that.

 

[SSDD]

MEA gap usually involves a leg with navaids that are hundreds of miles apart. Somewhere in the middle you would be beyond the operational service volume of both navaids. There are a few examples out west. J56 between FFU and MVA is 312 miles and the MEA is a woping 33,000'. Also J158 from LCU and MVA is 256 miles and the MEA is 23,000'. On J36 GTF and DIK are 354 miles apart.

MOCA and MEA gaps are two different issues. Mini seems to be confused. At 36 miles from the navaid, MOCA would not apply. At 21 miles you wouln't have an MEA gap, they'd just raise the MEA.

 

[minitour]

...MOCA and MEA gaps are two different issues. Mini seems to be confused. At 36 miles from the navaid, MOCA would not apply. At 21 miles you wouln't have an MEA gap, they'd just raise the MEA.

I understand the two different issues thing...

...but why wouldn't the MOCA apply at 36 miles?

It provides obstruction clearance and NAVAID reception to 22nm...now what if you're using GPS? You don't need NAVAID reception...just RAIM.

You still get "guaranteed" obstruction clearance.

During my oral, the examiner pulled out a chart and we talked about exactly that scenario (which is why I brought it up)...don't know which chart but it was a low enroute...anyone know?

Andy:
How would you say it?

-mini

 

[IP076]

Yeah, that whole GPS thing is confusing...Technically speaking, to use GPS as a sole source of navigation, you need to have a back up.

So, do you legally have a back up at the MOCA?

Just throwing it out, I used to say the same thing you are, now I'm just hearing lots of people saying that you can't legally do it.

I'll be honest in saying that I havent had the time lately to peruse the appropriate faa docs and find out, if anyone has an hard info one way or the other, I'm all ears.

 

[minitour]

Yeah, that whole GPS thing is confusing...Technically speaking, to use GPS as a sole source of navigation, you need to have a back up.

So, do you legally have a back up at the MOCA?

Just throwing it out, I used to say the same thing you are, now I'm just hearing lots of people saying that you can't legally do it.

I'll be honest in saying that I havent had the time lately to peruse the appropriate faa docs and find out, if anyone has an hard info one way or the other, I'm all ears.

That was the "argument" I made but the examiner quickly assured me that if I was flying along at the MOCA and lost RAIM or my GPS went out completely, I could just fly up to MEA and boom...be legal.

Then I asked about high density altitude affecting the airplane's performance and cieling...but I was quickly assured that if I wanted to pass my oral I would believe that GPS at the MOCA was more than legal...so I shut my pie hole...

of course he's also the same guy that tried to bust me for using the "crab and kick" method coming in....I'm inbound on the approach and we pop out like (guessing) 300 feet above MDA so I hang out at MDA until I see the runway...when I do, I start a descent and configure the beast for landing:
him: "you better stay there if you want to pass"
me: (thinking of 91.175) "Yeah it would be a shame to bust a reg now"
him: "so get back up there"

so we continue in and I've got white over white but I'm affraid to descend
him: "Are you going to land tonight?"

so I'm on short final
him: "You know you're not lined up with the centerline"
me: (looking at the LOC needle which is centered) "I'll kick it out in the flare"
him: "YOU ARENT LINED UP WITH THE CENTERLINE - MY PLANE"
me: "your plane"
*SLAM* (side loaded - he didn't kick it out)
him: "I shouldn't pass you just for that stunt"
me: "my landings aren't being tested here"

totally pi$$ed me off...but oh well...

Rant over

-mini

 

[IP076]

Man Mini, thats some ride....

I'd be pretty pissed if I ever ran into a DE like that, and knowing me, I'd tell him straight where to go....and correspondingly lose my ticket...

Here's a clip from AC-90-94, need to read the whole thing, but this is just a short excerpt....need to go to bed now...

4 EN ROUTE DOMESTIC AND TERMINAL. Domestic en route operations are defined as that
phase of flight between departure and arrival terminal phases, with departure and arrival points within
the U.S. NAS. Terminal area operations include those flight phases conducted on charted Standard
Instrument Departures (SIDs), on Standard Terminal Arrival Routes (STARS), or during other flight
operations between the last en route Wwaypoint and an initial approach Wwaypoint. In addition to the
criteria outlined in paragraph 3.b.( l), the following criteria applies:
a. Other navigation equipment should be installed and operational to receive the intended
ground-based facilities which define the route to be flown to the destination and any required alternate.
b . Ground-based facilities which define these routes must also be operational.
c. Aircraft should be equipped with an approved and operational alternate means of
navigation appropriate to the route being flown. This navigation equipment must be operational, but it
does not have to be actively monitored unless the RAIM capability of the system fails. The purpose of
these backup systems is to ensure that the aircraft can continue to the destination if something unforeseen
occurs to the avionics or GPS constellation.


I dont buy the whole climb back up thing, because what if the MEA is above your capability, say you dont have O2 available. One route I think of goes from PXR up towards INW, the MEA is 145 or 160 or something, and the MOCA is 9800'.

 

[minitour]

Man Mini, thats some ride....

I'd be pretty pissed if I ever ran into a DE like that, and knowing me, I'd tell him straight where to go....and correspondingly lose my ticket...
...
I dont buy the whole climb back up thing, because what if the MEA is above your capability, say you dont have O2 available. One route I think of goes from PXR up towards INW, the MEA is 145 or 160 or something, and the MOCA is 9800'.

Yeah I got pretty pissed during my oral when he was going over winds aloft telling me I was wrong on direction
730428 (30 or 33k)
me: 230 at 104 temp minus 28
him: wrong...speed is right, temp is right, direction is wrong
me: okay well lets just move on then

I learned early on that sometimes the examiners have this huge ego trip thing and you just have to go with it...

he also almost busted me on our first approach (ILS) when I put in 10* of flaps just before the FAF...
him: "you can't do that" (reaches and puts them back up)
me: "as PIC I want them in"
him: "uh huh..."

I knew going into it that he had an ego and a huge chip on his shoulder but I didn't wanna get too rowdy...I really wanted to ticket and I was my CFII's first signoff so I wanted to do good to help him out too...

anyway...

That was almost the exact same argument I gave him.
I just said, "What if you're in an IFR equipped 152 and the MOCA is 8000 and the MEA is 15000. Your service cieling is 14,700 so what do you do?"
him: "use your GPS"

Anyway rant #2 over....its done now and I don't ahve to worry about it

but thanks for the stuff on MEA gap guys! Leran something new every day!

-mini

 

[IP076]

You know, it makes me wonder, is there any course of action that you could take after a ride like that?

Obviously this guy has some problems, and probably is not a very safe pilot himself. However, the FAA seems hesitant to act on things like this, unless its the Scottsdale FSDO......then they revoke all the DPE's certs because they pass too many people.

 

[minitour]

You know, it makes me wonder, is there any course of action that you could take after a ride like that?...

...probably not anything good...

I'm sure it would be a "quit whining, you passed" thing...which is true...I just try to "warn" other students going to him for check rides so they know ahead of time what to expect...

I guess I shouldn't bitch...its not like he did bust me...and I'm not sure that he would have...probably just wanted to toss around the "I'm an examiner and you're a student so by definition I'm right and you're wrong" thing...

That said, I think he realized I flew the whole thing well within PTS and I more importantly, I think he realized that I knew that...so there wasn't a whole lot he could do...oh well...

"Sometimes when you get kicked in the balls you just gotta sit on some ice"

......thats what my Grandpa's always tellin' me......not real sure what it means but it sounds like it applies

-mini