I have recently been travelling on a 734, and I have noticed a peculiarity when landing. On at least two occasions on the aircraft, the gear have dropped early. Very early. The aircraft hadn't even turned onto the base leg one time at KPSP and the familiar thump could be heard before the wind could be heard against the gear. Another time the gear also went down very early, landing at KSFO. Does anyone know why this would be? It wasn't just a one off occurrence. It seems almost like procedure, and surely it's inefficient. On an unrelated note, I was on a Q400 landing on runway 16R some time ago at KSEA and the flaps didn't even start to be lowered until past KBFI, which I'm sure you can see is quite close to the runway. Does anyone know why these two occurrences would have occurred?


Thanks!


-abasa12

They were likely dropping the gear to add some drag to get the speed down, it can be done all the time if ATC give you vectors for a shorter final.

 

Regards,

Ró.

I know when KSEA is landing on the 16's many times they will require 180 knots until past Boeing Field. Most likely the situation you experienced on the Q400.

Landing gear offers a sort of speed brake for the aircraft. So as long as the reference speeds are maintained, the crew can deploy gear at any time. There could be many reasons for it too. Perhaps they have been instructed to slow for spacing, or perhaps they have a hectic approach procedure to follow and the gear down early clears up the checklist to free up their attention for the approach. They may have received their landing clearance a long way out, which might have included the friendly reminder to check gear down. They may be expecting a short approach turn to final so getting the gear down and the plane stabilized in landing configuration early reduces the struggle to configure the plane on a short approach procedure.

 

There's no right or wrong way about it, and for the amount of time the approach and landing phases take, there is little effect on efficiency of the flight at that point.

I know when KSEA is landing on the 16's many times they will require 180 knots until past Boeing Field. Most likely the situation you experienced on the Q400.

Is that just to get out of the airspace, or if not for what reason?

 

Landing gear offers a sort of speed brake for the aircraft. So as long as the reference speeds are maintained, the crew can deploy gear at any time. There could be many reasons for it too. Perhaps they have been instructed to slow for spacing, or perhaps they have a hectic approach procedure to follow and the gear down early clears up the checklist to free up their attention for the approach. They may have received their landing clearance a long way out, which might have included the friendly reminder to check gear down. They may be expecting a short approach turn to final so getting the gear down and the plane stabilized in landing configuration early reduces the struggle to configure the plane on a short approach procedure.

 

There's no right or wrong way about it, and for the amount of time the approach and landing phases take, there is little effect on efficiency of the flight at that point.

Alright - thank you very much!

Is that just to get out of the airspace, or if not for what reason?

That's a good question. It's not an airspace issue as the aircraft on 16 approach to KSEA will be in the bravo already. Most likely it was issued to maintain spacing with other aircraft following. restricting speeds helps the controller keep the ants shuffling along at the same pace, and at the right separation, in a straight line.

Is that just to get out of the airspace, or if not for what reason?

Has nothing to do with airspace requirements. As pegger74 said its mostly to ensure spacing requirements and make it easier on approach controllers. It would be pretty tough to ensure spacing if everyone is flying at different speeds. In reality Seattle is similar to many places. Its pretty common to hear "maintain XXX knots till the marker, cleared XXX approach" Boeing field is basically at the outer marker for the runway 16 approaches and it gives the pilots a visual reference point.

That's a good question. It's not an airspace issue as the aircraft on 16 approach to KSEA will be in the bravo already. Most likely it was issued to maintain spacing with other aircraft following. restricting speeds helps the controller keep the ants shuffling along at the same pace, and at the right separation, in a straight line.

 

 

Has nothing to do with airspace requirements. As pegger74 said its mostly to ensure spacing requirements and make it easier on approach controllers. It would be pretty tough to ensure spacing if everyone is flying at different speeds. In reality Seattle is similar to many places. Its pretty common to hear "maintain XXX knots till the marker, cleared XXX approach" Boeing field is basically at the outer marker for the runway 16 approaches and it gives the pilots a visual reference point.

 

 

Thank you both. Makes sense now.

The beauty of the Q is that it can go fast and slow quick on final approach. Usually what controllers did to us is make us fly at 250 all the way to a close final in someones tailpipes and then said go to final approach speed which is 120 knots until Vref of 85-105 knots

Gear is sometimes dropped to help the slowing down process, not that I agree with that procedure.

Gear is sometimes dropped to help the slowing down process, not that I agree with that procedure.

Using the gear as an airbrake is common. Whether you agree or not is inconsequential. Every object that falls outside of the regular "clean" configuration of the airframe changes the handling characteristics of the aircraft by inducing drag. Flaps, spoilers, gear, etc...they all cause drag and thus slows the plane down. The pilot can't really step on the brake peddle, so they use the various drag inducing components to modify their flight characteristics. Completely normal, safe, and expected.

Using the gear as an airbrake is common. Whether you agree or not is inconsequential. Every object that falls outside of the regular "clean" configuration of the airframe changes the handling characteristics of the aircraft by inducing drag. Flaps, spoilers, gear, etc...they all cause drag and thus slows the plane down. The pilot can't really step on the brake peddle, so they use the various drag inducing components to modify their flight characteristics. Completely normal, safe, and expected.

ok

Can you still use the speedbrake when the aircraft is in a flaps up wheels down configuration?

 

Jon

jonss1948, on 09 Apr 2013 - 07:40, said:

Can you still use the speedbrake when the aircraft is in a flaps up wheels down configuration?

Sure. Deploying spoilers can help with many things, like faster rates of descent. You can use spoilers in a gear up flaps up too, at cruise if you need too. It is not uncommon for airliners to put out the spoilers in the cruise portion of the flight to burn off extra fuel (weight) if an overweight situation at landing is projected. Also the spoilers on some modern liners may actually work to supplement the trim of the aircraft in flight.

 

The biggest thing to consider is your reference speeds. What speed can your gear go down at? What speed can you drop flaps. What are your minimum maneuvering speeds in clean and dirty configurations.

 

There is a lot more to think about with the use of control surfaces than just "can I do it".