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wTom
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Joined: Sat Jan 07, 2017 1:57 am

Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 3:23 am

Second post here. Thanks to the admins for an awesome forum and because I am writing this at 11:15PM means I really am curious of something.

Today I flew from Philly to Columbus Ohio, quick flight (an hour) on an ERJ-175. We descended through the bumpy base of cumulus that I would guess was around 10,000. We were holding altitude when that sound...boom, whoosh... Gear is coming down. It caught me by surprise because as I sit at a window seat above the wing, the flaps or slats were not down, or even started to come down.

I thought crap, a no flap landing? Did something happen? We took off with slats and flaps so I knew they were working prior.

Two minutes later, the slats were deployed. Followed by flaps. Why?

CMH is not a busy airport so I cannot believe the landing sequence was changed.

Thanks for reading. Any feedback?
Last edited by wTom on Thu Jun 21, 2018 3:41 am, edited 1 time in total.
 
Sean-SAN-
Posts: 815
Joined: Tue Aug 13, 2002 4:02 pm

Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 3:31 am

On most planes the gear extension speed is higher than the first flap speed. The gear can be used in conjuction with speed brakes to slow down. Nothing to worry about.
 
sdh9
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 3:35 am

Rubber speed brake. Totally normal.
 
wTom
Topic Author
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Joined: Sat Jan 07, 2017 1:57 am

Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 3:39 am

Ah...interesting. Thanks all. Just seemed out of the ordinary since I fly a lot and this was the first that I've seen this. Thanks again!
 
WN732
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Joined: Sat Feb 26, 2011 12:49 am

Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 3:56 am

WN does this all the time. Usually when they're in a pinch to get down and slow down fast. They try to get in as quickly as they can. Once I saw gear down first, spoilers and flaps deployed with spoilers still extended. We were approaching PHX. I asked the captain when we landed why we slowed down so quickly. His answer was that ATC wanted the aircraft to expedite their approach as the flow pattern was going to switch. We were the last aircraft to land on the 25's. There were already aircraft holding on the opposite side waiting to takeoff by the time we landed.
 
kaitakfan
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 5:09 am

I used to fly for Republic Airlines based in CMH on the E175. Usually we could keep the speed up at our discretion as there was no other traffic to follow. Many pilots would fly fast until just about intercepting the glide slope. Made for a very uncomfortable ride for the customers, but gear down, full speed brakes and flaps on speed schedule and the plane would be stable by 1000 ft.
 
whywhyzee
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 12:24 pm

On a UA 757, DEN-KOA a couple years ago, they did the same thing. Made for a fun descent!
 
stratclub
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 2:57 pm

On short flights could gear down first help cool the tires and brakes?
 
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ojjunior
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 4:58 pm

stratclub wrote:
On short flights could gear down first help cool the tires and brakes?


I don't think there's a flight short enough not to give time to cool the mains from previous takeoff...

But as a concept yes, it does. Speed is always a cooling system, see your car intakes.
 
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Francoflier
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 5:05 pm

The crew might unexpectedly have gotten vectors towards the runway with a lot less track miles than they initially thought, prompting a 'Dive, Dive, Dive!' maneuver which often starts with throwing out whatever drag your speed allows you to... first among which, the wheel thingies.

Did you see the boards coming up as well?
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
Woodreau
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 21, 2018 5:08 pm

stratclub wrote:
On short flights could gear down first help cool the tires and brakes?


On short flights, I might get the gear down early (in addition to keeping the APU running from gate push back all the way to after blocking in at the destination and flying at a lower altitude) to increase the fuel burn to get the aircraft below the max landing weight.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
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akiss20
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Re: Gear Before Flaps::PHL to CMH

Fri Jun 22, 2018 2:26 am

ojjunior wrote:
stratclub wrote:
On short flights could gear down first help cool the tires and brakes?


But as a concept yes, it does. Speed is always a cooling system, see your car intakes.

The SR-71 and Apollo capsule wants a word with you on that one... :)
Change will not come if we wait for some other person or some other time. We are the ones we've been waiting for. We are
 
Georgetown
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Re: Gear Before Flaps::PHL to CMH

Fri Jun 22, 2018 4:27 am

It’s a bummer, I asked this very question a while back and there was a great thread on it. Alas, a.net deleted it.
Let's go Hoyas!
 
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PowerliftDrsTX
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Re: Gear Before Flaps::PHL to CMH

Fri Jun 22, 2018 12:58 pm

wTom wrote:
Ah...interesting. Thanks all. Just seemed out of the ordinary since I fly a lot and this was the first that I've seen this. Thanks again!


What everyone else said. Once, after being help way up for way too long coming into JAX and repeatedly asking for lower, I threw the gear out with the boards at 17,000 to get down.
 
stratclub
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Re: Gear Before Flaps::PHL to CMH

Fri Jun 22, 2018 8:01 pm

akiss20 wrote:
ojjunior wrote:
stratclub wrote:
On short flights could gear down first help cool the tires and brakes?


But as a concept yes, it does. Speed is always a cooling system, see your car intakes.

The SR-71 and Apollo capsule wants a word with you on that one... :)

I suspect that if you extended the gear at Mach 3.3 you would probably forget about planning for you arrival at you destination and run the emergency check list for exiting a disintegrating aircraft. The Apollo capsules didn't even have wheels and brakes and certainly the external temp lowered considerably by the time the capsule splashed down. :) :)
 
GalaxyFlyer
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Re: Gear Before Flaps::PHL to CMH

Sat Jun 23, 2018 8:39 pm

ojjunior wrote:
stratclub wrote:
On short flights could gear down first help cool the tires and brakes?


I don't think there's a flight short enough not to give time to cool the mains from previous takeoff...

But as a concept yes, it does. Speed is always a cooling system, see your car intakes.


Depending on type and if the gear is fully enclosed in the wells, they won’t cool much on a 30 minute flight. Extending early would cool and airborne cooling times are pretty short. If the plane had flown several short legs, it might build up enough heat to need cooling. Taxiing a C-5 for a few miles would add considerable head into the brakes and wheels.

GF
 
mxaxai
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Re: Gear Before Flaps::PHL to CMH

Sun Jun 24, 2018 2:51 pm

I've seen some take-offs delay gear retraction by a bit, typically after taxiing to the far end of the runway, downhill. I think that was done to cool the brakes prior to stowing the gear in the wells, where heat would dissipate poorly.
 
e38
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Re: Gear Before Flaps::PHL to CMH

Sun Jun 24, 2018 8:36 pm

Quoting wTom (Reply # 4), "Just seemed out of the ordinary since I fly a lot and this was the first that I've seen this."

Tom, what you experienced IS somewhat "out of the ordinary" but not completely unusual depending on the circumstances. On the aircraft I fly, the normal sequence for gear and flap extension is "Flaps 5, Flaps 15, Gear Down, Flaps 25, and Flaps 40." However, it is acceptable to vary the sequence depending on the situation.

Approaching an airport, it is not uncommon for Air Traffic Control to keep you high for traffic separation; occasionally terrain as well; then when clear of traffic and/or terrain as appropriate, clear the aircraft for an approach to the airport (generally we're talking about a visual approach in this case).

For many aircraft, lowering the landing gear is by far the best drag device available to the pilot to facilitate a descent and speed reduction.

In the situation you described approaching Columbus, my guess is that the aircraft was at 250 KIAS (probably above flap extension speed--I'm not familiar with the ERJ-175), fairly high, when the controller cleared the aircraft for a visual approach. The pilots lowered the landing gear first to initiate the descent and reduce airspeed, then continued to configure with flaps as airspeed decreased.

Quoting stratclub (Reply # 8), "On short flights could gear down first help cool the tires and brakes?"

Yes, but that is generally done after takeoff, not prior to landing. If there is concern with regard to brake temperature, the normal procedure would be to leave the landing gear extended for a specified period of time following takeoff. You would not want to retract the landing gear and have it stowed in the wheel well if there is a possibility of overheat, so you cool them (if required) prior to retraction. For some aircraft, it is also procedure to leave the landing gear extended after takeoff from a snow, ice, or slush covered runway for a specified period of time to allow contaminants to blow off so as not to freeze in the wheel well at high altitude.

e38
 
WPvsMW
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Re: Gear Before Flaps::PHL to CMH

Sun Jun 24, 2018 9:28 pm

Don't know about the E-jets, but B and A have brake temp sensors, so after TO the PIC would leave the gear down until the LG wasn't toasty.
https://aviation.stackexchange.com/ques ... re-sensors
 
strfyr51
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Re: Gear Before Flaps::PHL to CMH

Mon Jun 25, 2018 5:51 am

stratclub wrote:
On short flights could gear down first help cool the tires and brakes?

most definitely!
 
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kearnet
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Re: Gear Before Flaps::PHL to CMH

Thu Jun 28, 2018 11:11 pm

WPvsMW wrote:
Don't know about the E-jets, but B and A have brake temp sensors, so after TO the PIC would leave the gear down until the LG wasn't toasty.
https://aviation.stackexchange.com/ques ... re-sensors


A few years ago while flying DEN - BOS on B6, the PIC dropped the gear about 5 mins after retracting it after takeoff.

It was a delayed red eye (first flight out after the northeast groundings from Hurricane Irene.) and most folks were already dozing in the dark cabin.

Even I shrieked when it happened as it sounded and felt like we'd blown a cargo door.

Turns out they got a hot wheel warning and wanted to cool them off. Seems to have worked as the gear was retracted again a few mins later and we continued on as normal.
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