Good News for SWA Pilots!!!??? Breaking News?

[A Squared]

Nice post concerning required aircraft operating characteristics, but unless you're an experimental test pilot participating in an aircraft certification program, you're reading the wrong regulation. Note the the title: Part 25: AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES. You need to be reading Part 121: Operating Requirements: Domestic, Flag and Supplemental Operations.

I included the hyperlink so you can read Section 25.1 Applicability. Part 25 has nothing to do with operating the aircraft after it has earned it's Airworthiness Certificate unless you are working on an Supplemental Type Certificate.

GV

Hmmm, I don't see a subpart to 121 titled "Operating Requirements: Domestic, Flag and Supplemental Operations."

You got a specific reference for that?

 

[satpak77]

Hmmm, I don't see a subpart to 121 titled "Operating Requirements: Domestic, Flag and Supplemental Operations."

You got a specific reference for that?

That is the name of the Part 121 section

 

[A Squared]

That is the name of the Part 121 section

Ahhh, OK I gocha, it's the title of all of Part 121, I was looking for a subpart with that title. OK, question still stands, where in Part 121 does it address reverse in landing perfomance?

 

[Oakum_Boy]

I too have never flown a jet that used thrust reversers as part of the landing data. Everything is based on brakes and lift killing devices (Spoilers etc.)

Dunno about the ERJ but nothing I ever flew in the corporate or airline world is based on thrust reversers for landing.

Well, maybe. What y'all are talking about is DRY, FACTORED landing performance. The numbers that are in the airport analysis book, or whatever comes over your ACARS is for DRY runways. Those numbers do not "factor" the use of thrust reversers.

Everything changes, however, when you are approaching your destination, and low-and-behold, there is 1/4" of wet snow covering the runway. Now what? Well, you must consult the ACTUAL landing distance numbers for a CONTAMINATED runway. In the CRJ, you will find them in QRH vol. 1. Those numbers have accounted for use of the thrust reversers.

At my airline, we can dispatch to an airport with contaminated runways, based on FACTORED performance numbers for a DRY runway. Sounds dumb, right? Well, the fact is, that runway condition is variable, and may change during your time enroute such as: intensifying or diminishing snowfall, runway clearing, etc.

Personally, I'll take into account all available information, and push for cancellation, or diversion of the flight if it appears landing at the planned destination would not be prudent.

Comments?

 

[Flystr8]

Landing data two engines is based on no reverse, takeoff data the same. The only time reverse comes into play is landing with one engine, and stopping with a failure prior to V1. The bottom line is that MDW is way too short for Part 121 operations in any kind of severe or abnormal weather. The airport managers and airline officals are full of BS. The operate there because it is cheap, cheap, cheap and Chicago Airport Authority like the money. They push the airplanes and the pilots then fault the pilots because we are not perfect. This industry stinks, and the pilots are the ones that take the windfall......and we get paid too much....SURE>>.

This is an awesome statement and I could not agree with you more. Its so true. Pilots are pushed and then blamed when the outcome isn't perfect. Its total BS.......and yes, the pay sucks too. Its no doubt we dont do it for the money. If flying wasn't fun the aviation world would be screwed.

 

[Rally]

Quit speculating Rally! Again, you are making an assumption that perhaps they landed too far down or too fast. All indications point at the fact that they were right where they needed to be. It's unprofessional to make such assumptions and second guess anyone here. One last thing Rally, I hope that you do understand that this could have happened to anyone of us!

Was'nt trying to speculate I think its highly likely that it is either all or partially NOT the pilots fault. But this aircraft did'nt just overrun a little it over ran ALOT. Probably 1000-2000 feet right? Again not trying to point fingers just trying to understand.

 

[Flystr8]

Reversers or not should'nt the -700 be able to stop in that length of runway with that amount of snow UNLESS they were too fast or too long?

It was reported that the aircraft picked up a tailwind on final approach. Not sure how much that will factor into the outcome but it was an issue.

 

[Oakum_Boy]

Landing data two engines is based on no reverse, takeoff data the same. The only time reverse comes into play is landing with one engine, and stopping with a failure prior to V1.

This is wrong. That data is for a dry runway. When you have a contaminate on the runway, all bets are off. You must use actual landing distance data for a contaminated runway. If your airline or manufacturer does not publish that information, look out. You're gonna be dissapointed in that "no thrust reverse, factored landing distance" calculation you did at the gate. See ya-

 

[EagleRJ]

Nice post concerning required aircraft operating characteristics, but unless you're an experimental test pilot participating in an aircraft certification program, you're reading the wrong regulation. Note the the title: Part 25: AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES. You need to be reading Part 121: Operating Requirements: Domestic, Flag and Supplemental Operations.

I included the hyperlink so you can read Section 25.1 Applicability. Part 25 has nothing to do with operating the aircraft after it has earned it's Airworthiness Certificate unless you are working on an Supplemental Type Certificate.

GV

Part 25 is not of consequence only to test pilots during certification.

If you look in the limitations section of a transport category aircraft's AOH, I suspect you will see Part 25 mentioned as a basis for the data. Part 25 regulations are used along with Part 121 regulations in governing the daily operation of an airliner.

A good way to think about it is: Part 121 tells you how much runway is required, and Part 25 tells you how much runway is actually used.

 

[satpak77]

uh...not so good news...

while not official POH guidance, nonetheless....

http://www.b737.org.uk/limitations.htm

"No tailwind component allowed on contaminated runways"

this is independent of any TR problems or other stuff

don't know if this applies to the 737-700....came across it when I was reading up on 737 performance data

 

[TR4A]

while not official POH guidance, nonetheless....

http://www.b737.org.uk/limitations.htm

"No tailwind component allowed on contaminated runways"

this is independent of any TR problems or other stuff

don't know if this applies to the 737-700....came across it when I was reading up on 737 performance data

This is posted on that site:

"Note: Not all limitations given here are AFM"

 

[satpak77]

This is posted on that site:

"Note: Not all limitations given here are AFM"

agree...just posting what I found for an FWIW type thing

 

[9GClub]

So we're tossing out reverser data for a dry runway but including it for a wet one huh? Why do we wanna add the reverser variable to an already full wet runway equation? This is SOP?

So these guys are expected to bleed off 120KT on a [6522'-1000'=] 5522' contaminated runway with no EMAS, a tailwind, and a better-be-functioning TR setup. No thanks.

 

[satpak77]

So we're tossing out reverser data for a dry runway but including it for a wet one huh? Why do we wanna add the reverser variable to an already full wet runway equation? This is SOP?

So these guys are expected to bleed off 120KT on a [6522'-1000'=] 5522' contaminated runway with no EMAS, a tailwind, and a better-be-functioning TR setup. No thanks.

dude when you solo your 152 get back to us.....

 

[Oakum_Boy]

So we're tossing out reverser data for a dry runway but including it for a wet one huh? Why do we wanna add the reverser variable to an already full wet runway equation? This is SOP?

So these guys are expected to bleed off 120KT on a [6522'-1000'=] 5522' contaminated runway with no EMAS, a tailwind, and a better-be-functioning TR setup. No thanks.

Yes, absolutely! Thrust reversers have negligible effect on a dry runway!
Surprised? Well, hopefully you're not equally surprised that on a wet runway, the coefficient of friction (mu) is diminished. Brakes are effective, but not nearly so as thrust reversers. As friction decreases, so does the effectiveness of the brakes. Therefore, thrust reverse becomes more effective than brakes!

Wet and contaminated landing distances are calculated using thrust reverse as well as brakes. It may seem illogical, but you have to consider more complex issues on transport certified aircraft.

Lesson over.