I don’t fly CRJs so I am reaching out to someone who does. I was curious what kind of climb gradient a 200 can achieve off a 5200’ field elevation, on say, an 80° day, at gross?

can anyone help?

Im on an airport board and we are considering paying for a departure procedure. The airport is served by OO. When we called the company to ask what kind of improvement they needed to not be weight restricted they said they couldn’t tell us until after we had it built (over simplified version of the conversation). Obviously, we don’t want to spend this kind of money without some knowledge of what it will gain us in reliability.

Any help would be greatly appreciated!

Currently the airport has a textual departure that requires a climb of 420’ per NM to 7400’.

Our rough assessment from a recent feasibility study shows an improvement of 396’ per NM to 6100’.

Is that improvement significant?

 

Whom does one pay for a departure procedure? I would suspect that Aerodata provides the runaway analysis to Skywest since they have done so for every airline I've worked for. I would start with them. The improvement you mentioned would help somewhat but there may be something else that would help significantly more (stopway, clearway, etc.). What you can't fix is Denver (my best guess based on the information you gave but whatever hub) weather. If they need to carry an extra hour of fuel for alternate requirements that's passengers they can't carry. You are considering spending money to increase their maximum takeoff weight because that's what is in your control but what if they are landing weight limited instead? You need answers to these questions.

 

This is a professional inquiry, so you really should be asking professionals like SkyWest (I know you tried) and AeroData, not some randos claiming to be pilots on APC.

That being said, it's also possible that the limiting factor here is single engine performance. And, if my calculations are correct, the slatless wonder will barely climb with one engine in your requested conditions. Like, in the realm of 100 ft/nm, if not less, kind of climb. If aerodata can create a single-engine procedure that can keep the aircraft clear of terrain with that sort of climb gradient, then maybe. Depending on the airport, it's possible that there already ARE special single-engine procedures, and changing the published instrument departure may or may not change that.

Please do not take my ballpark 100 ft/nm number as a target number for any departure. Calculating climb performance is a very, very complicated process, and you should get a professional evaluation from professionals before spending tax payer money on anything.

The 200 is also kinda just an underpowered jet in general, so not likely that your limited performance improvements will help that much. But that's just my 2 cents.

 

I would love it to be a professional inquiry, but that isn’t my expectation here😁… I was just hoping for some generalizations like along the lines of what you said. And you’re exactly correct, the limiting factor is SE climb gradients. Since we can’t move the mountains, we are drawing a graphic procedure that avoids them.

Thanks for that! I’ve never flown the 200 and my knowledge is limited. But the whole board looks at me whenever technical questions pop up because they think that all airline pilots know all the nuances of different types of planes😁

 

There are companies out there who can build approaches and departures. Alaska Air Group, for example builds a lot of RNPs. You’ll recall the Delta lawsuit over the approaches into Juneau. When you do that the entity who commissioned it becomes responsible for upkeep costs. Not the feds.

Good point about Alternate and holding fuel for DEN and we are aware of that. Our problem as an airport is when they bump 22 people in the summer it destroys passenger confidence in reliability. So we end up “leaking” passengers to other airports. We’re trying to solve the reliability issues and I appreciate your points!

 

I once did this for a living but I'm back to being plain old line swine for the past few years so someone should double check my work.

One question to ask Skywest is if they have the authorization for and have paid for payload optimized V1. If they are only using balanced field length performance numbers then they are certainly leaving passengers behind unnecessarily at times.

Aerodata doesn't care about meeting the obstacle departure procedure climb gradient one engine inoperative so changing that parameter alone isn't going to increase the allowed takeoff weights if single engine is what's limiting. So that's why it is critical to know exactly what the issue is. They are designing their own obstacle avoidance path and it doesn't need to meet TERPS standards.

It would also be useful to know what obstacles are impacting the 40:1. I agree that you can't move the mountain but if it turns out to be something else closer to the airport then you can show that to the city/county leadership and see if it can be relocated or shortened.

PAJN is a fascinating case study. The FAA procedures rely on the lower elevation of the 'engineer's cut' to get the aircraft over the hill before the final turn. Perhaps AAG does the same just without needing to see it visually due to high levels of navigation accuracy. If your terrain problem area isn't that big you might even be able to make your own cut for similar or less expense than designing and maintaining a DP.
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What airport is it?

 

The hypothetical Jellystone Regional Airport is about 5200' elevation. It is near the fictional town of Ydoc, Gnimoyw.

Per TERPs, Runway 22 has a Departure procedure of:

Climb on heading 221* to 6600, then climbing left turn to intercept the DOC R-180 to DOC VOR/DME. This can be performed with a minimum climb gradient of 420' per NM to 7400', as long as the weather adheres to Standard Takeoff Minima (or less than Std if the operator has Op Spec C078).

What does this mean? What is this number "good for?"

I would like to emphasize that these are TERPs procedures, and they are for an all-engine climb. They are frequently NOT the best lateral & vertical flight path for obstacle avoidance.

Several cautions:
tallpilot may have hinted at this, but I'll confirm it. TERPs gradients and OEI gradients do not have anything to do with one another.

TERPS gradients will not assure clearing close-in obstructions. TERPs gradients can also reduce takeoff weights significantly & unnecessarily. Also, using TERPs alone does not satisfy 121.189.

I'm not claiming Skywest is not satisfying part 121 rules. I'm pointing out TERPs is just the beginning of the story.

Let's shift the focus to engine out procedures.

Contingency procedures are completely separate, and per FAR, are the responsibility of the individual operator. An operator's EOP is based upon one-engine inoperative performance.

Once the aircraft & crew are OEI, it is an emergency situation and the emergency takes precedence over:
Air Traffic
Noise Abatement
SID and DP
Any other Normal Operational considerations

In other words, once an engine fails, "you can toss TERPs right out the window." You then follow your operator's EOP for that runway.
Key takeaway: This is an emergency and ATC has zero idea what you are doing from this point on. They do not have your EOP. It has nothing to do with any published SID, ODP, or TERPs criteria.


Someone from (OO) might be able to confirm:

What is the current OEI departure procedure for the mountain airport where you are on the board? What flight path/corridor is being utilized? Is there a more efficient path that avoids more obstacles & terrain? Perhaps it is in need of review/update?

Deer Valley is a great example. The TERPs path goes over lots of high terrain and is absolutely terrible. If Aerodata is lazy and just makes minor alterations to it (for an EOP), you are leaving pax behind.

Does (OO) operate using balanced field or unbalanced?
The Bombardier AFM might default to balanced field (many manufacturers do), but using a runway analysis with unbalanced numbers could increase payload. (I'm not familiar with the -200, someone from (OO) should chime in.)

Balanced field means using TORA for both Accelerate-Go and Accelerate-Stop.

With an "unbalanced" field, using TODA for Accelerate-Go and ASDA for Accelerate-stop could result in leaving fewer passengers behind.

I haven't heard it referred to in that way, but unbalanced field may be what tallpilot means when he says "Optimized V1."

In some of the earlier posts, it was said in so many words:

"the -200 can only climb 100 ft/nm OEI"
"the -200 is the slatless wonder"
"the -200 is underpowered"

APG, Aerodata, et al, are not strangers to runway analysis. They build tailored EOPs for anemic jets to pull pax or cargo out of challenging airports like Aspen, Eagle, etc, all the time.

The CRJ-200 is certified. It has the minimum OEI climb gradient for a two-engine aircraft. They can work with that.


tl;dr
Talk to someone at Skywest that knows what they are talking about. Do they have a performance engineering/compliance/ops specs dept(person)? The reason you need to talk to the operator, is because they are responsible for the EOP. And I am fairly certain the all-engine climb is not the limiting factor for your airport. As an airport, buying a DP to publish is not necessarily going to help matters.

420'/nm to 7400' is a 180 knot, no wind, 1260 ft/min climb to 2300' Height above airport.
Is a 1300 fpm climb at 5000' elevation during a 80F summer day really that big of a hurdle for a CRJ-200? Can a -200 pilot comment on all-engine hot & high performance? I do not know.

But find out. Ask them if they use unbalanced field lengths. You cannot move mountains, but the path can be changed. Find out what the operator's EOP is for runway 22 and perhaps it can be improved.

 

Not all mountain towns deserve RJ service.

Bring back 121 turboprops!

 

I can think of one I recommend.