OEI climb out with the gear locked down

Butters Stotch

Butters Stotch

Well-Known Member
Hello guys. Today i had my annual systems review class for the Embraer 190 (other inputs will also be appreciated). And we had a discussion on the Aircraft's performance with the gear down.
Scenario 1: On a ferry flight to a maintenance base, we had the aircraft dispatched with the gear down and locked with pins. So you can't raise the gear under any cirscumstances. Suppose that you have an engine failure during the takeoff right after liftoff. Is there any regulation that determines which is the minimum aircraft performance? FAR 25.121 (a) states that the aircraft must be able to keep a steady positive climb gradient. But to which point? I don't think that FAR 25.121 contemplates the situation that your gear will remain down.
Scenario 2: The Embraer 190 is my first jet transport aircraft so it's the only aircraft i'm familiar with the hydraulic system. So, suppose now you're on a regular flight (with passengers), and you have an engine 2 separation. I believe you would lose all the hydraulic system 2 (including the skydrol)and therefore the ability of the PTU to raise the gear. So you would be OEI and with your gear stuck down.

I know those are more than unlikely - easier to win the jackpot scenarios. But for the sake of the argument: are you guys aware of any certification requirements on similar situations? If yes, can you please reference it for me?

PS: We had access to this table during the class. Disclaimer: not to be used in flight!!! What do you understand from it? Suppose you're taking off with 47 tons (some 100.000lbs), which is a pretty common weight for the 190. I believe you won't be able to fly at all. Do you understand the same? Wasn't the aircraft supposed (per certification) to be able to climb OEI, under any circumstance, to at least the MSA of any given field, considering you comply with the takeoff limitations (structural, field lenght, climb)?

I truly appreciate your attention for any help you can provide on this matter!
 

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Ok. First thing. Part 25 is for certification. You don't operate under part 25.

The ferry permit would give you relief from the need to meet certification climb requirements (1.6%). Second. Empty, light fuel load, etc. the airplane should be able to climb OEI with the gear down.

Part 25 and TERPS are two seperate and distinct things. For the most part a transport category jet will be able to climb with OEI, gear up, flaps in any approved takeoff position; provided the performance limits are observed.
That means you can't just load up the jet and take off at max weight at all density altitudes.
 
"Disclaimer: not to be used in flight!!! What do you understand from it?"

It's a planning or dispatch document. The gear down performance stuff is to plan a gear down ferry flight. If you got stuck with the gear down in flight there is no reason to refer the gear down performance data other than for reference. It's not blessed by the FAA for that scenario.
 
Thanks for the reply, guys. I appreciate you took your time to do so.

Dugie, i'm aware i don't operate under FAR 25, and that it is for certification. Let me put this other way: is a jet transport required to climb OEI with the gear, for any given circumstance, locked down? And by required, i mean required by certification standards.
- If it is, where in the regulations say that it is?
- If it is, what is the minimum climb gradient? Until the MSA? Until the end of the final segment?

In the E190, if you lose the hydraulic system 2, you can't raise your landing gear. So, if you have an engine separation on liftoff, with a catastrophic loss of your hydraulic fluid, you're facing a situation where your gear is still down, and you're OEI. And you won't get that gear up. What i understand from the table, if you're taking off with 47 tons (on a regular flight, with pax, totally on the envelope), your altitude capability is 0. So you won't climb a foot on that situation and you will crash. Given the fact that an engine separation is a possibility known to the manufacturer (since you have that on the QRH), and the aircraft must fly for any given situation on the QRH (if adressed properly by the crew), i believe that the plane should be able to fly. But it's not what i understand from the table i attached on the previous post. So that's why i'm asking if a jet transport aircraft, certified per FAR 25, is required (certification wise) to climb OEI with the gear down. And, again:
- If it is, where in the regulations say that it is?
- If it is, what is the minimum climb gradient? Until the MSA? Until the end of the final segment?

DE727UPS, i agree with you. But for the sake of the argument, i think we can infer that if you're taking off with 47 tons (on a regular flight, with pax, totally on the envelope), your altitude capability is 0 on that situation i mentioned (unable to raise the gear due to mechanical issues and OEI).
 
"DE727UPS, i agree with you. But for the sake of the argument..."

Enjoy your scenario. The FAA doesn't care if you die. They just want to cover their bases and their ass.....es. Wonderful world we created....
 
I think positive climb is just what it is - 1fpm is positive. I would infer those dashes on the chart to imply that you aren't getting a positive rate at those weights/temps.
 
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