Jump? How high?

[[email protected]]

When an MEA changes to a higher altitude and no crossing
restriction is published, what minimum climb gradient is required and
where is this requirement published?

With varying answers, most pilots feel that the climb gradient is simply a
minimum of 500 FPM. This to me seems unlikely as a light aircraft may
climb at 90 kts and a large Transport Category aircraft will climb at much
higher speeds. Obviously if they both climb at 500 FPM the light aircraft will
climb in a much shorter distance than the larger jet.

If you have any answers, they would be much appreciated.

[mustafagander]

As I understand it, when the MEA changes, be at or above MEA at that point, period. It matters not how you achieve this, just be there.

[HugMonster]

MEA is what it says - a minimum. It is not a clearance, or a cleared altitude. Don't get confused with the 500 fpm which is required for aircraft to comply with when under radar control. As mustafa says, it matters not how you get there (or above). Just be there, or be in danger of a close encounter with cumulogranite or TV masts or similar...

[Portly]

mustafagander is quite right.

The 500fpm restriction applies at all times, not just under radar control. It is efecctively one of the instrument flight rules. Do you report to ATC every time your RoC or RoD drops below this value? You should - even if it is only as a consequence of poor autopilot design (Boeing again!)

[A Squared]

I have to disagree with Hugmonster and Mustafagander. In the absence of a minimum crossing altitude, you may cross the Navaid or fix at the lower MEA and then begin your climb to the higher MEA of the next segment.
From the Jeppesen Sanderson Instrument Rating Manual: "When an MEA changes to a higher altitude, obstruction clearance normally requires you to begin your climb upon reaching the fix where the change occurs"

And from The Instrument Flight Training Manual, Peter Dogan: "If you are at the MEA and it increases, you should begin your climb to the new MEA at the point where the change occurs."

At least that's the way things are in the US, your mileage may vary.

So, jdelfman's question still stands, the selection of MEA's and the choice not to specify a MCA, obviously must be predicated on an assumed minimum climb gradient. Anyone know what it is?

[mustafagander]

MEA or LSALT in Oz AIP terms give no tolerances for climb to satisfy LSALT/MEA.
Oz AIP GEN 3.2-3 para 2.2.1 is clear that the LSALT applies from the fix/nav aid.
See also GEN 3.3-13 sect 3 on how LSALT is calculated.
Let's also take a peek at Jepp Intro Chart Glossary p8 MEA ".....applies entire..segment or route between the radio fixes defining the airway..."
I see no latitude at all here - be at or above MEA or be illegal and dangerous, period.

[This message has been edited by mustafagander (edited 25 September 2000).]

[[email protected]]

Thank You "ASQUARED" for being the only one so far to see my point. If I rent a Cessna 172 and climb on an airway at 500 FPM at 90 kts (typical figures if I'm low enough), I will climb 1.5 miles per minute at the minimum rate. If I go back to work the following day and fly the same route and choose to climb at 500 FPM at 420 kts, I will climb at 7 miles a minute at the minimum rate. If the MEA changed only 1000 ft. I would climb for two minutes in the jet, it would take me 14 miles to climb. But it would only take me 3 miles to climb in the venerable Cessna. Where is the obstacle located that I am trying to avoid?

[A Squared]

Mustafagander,

Like I said, that's the way it is in the US, apparently things are different in Oz. From the US aviation regulations Part 91.177 b): Climb. Climb to a higher minimum IFR altitude shall begin immediately after passing the point beyond which that minimum altitude applies, except that when ground obstructions intervene, the point beyond which that higher minimum altitude applies shall be crossed at or above the applicable MCA (minimum crossing altitude)

Could be a rather nasty misunderstanding for a US pilot flying IFR in Oz. It's not clear where jdelfman flies, but obviously if it's in Oz, he'd best cross the fix at MEA.

jdelfman, sorry, still no answer to your question.

[bunyip]

One reason for the Aus/US difference is that in Aus there is only one definition of MSA for the route sector and that is what it says it is. The sector has an MSA published and that altitude is good for the route between the fixes defining the sector with about a 4nm buffer each side and at each end of the sector. So you could theoretically cross the fix into the next sector with a higher MSA and then climb, provided you could reach the new MSA within the 4 mile buffer. In practice however, nobody would even try and so the rule is that you should achieve the new MSA before crossing the fix.
Same thing applies when going from a higher to a lower sector MSA. Don't descend until past the fix.
In the US it is the same if the sector is based on MSA, but often it is based on MEA or Navaid Reception and not MSA; in that case it is not imperative to climb beforehand. If it is based on MSA/MCA then it is stated so on the chart amd an early climb would be required.
If a US pilot is flying anywhere else in the world, he should bone up on this.