Landing with speed brakes deployed

[PT20J]

Just don't carry it too far. I was once doing an IPC for someone in an Archer at SJC and we were asked to keep our speed up to the middle marker on the ILS 30L. Bob carried it a bit too far and crossed the threshold at 130 kts. As we progressed, I could see the 2000' remaining runway edge lights coming into view and the tower must have taken note also because they began calling out runway distance remaining. With less than 1000 ft. to go, when I was certain Bob would do the right thing and go around, he planted it on the runway and hit the brakes which caused an ineffective squealing fishtail. I reached for the flap lever and pushed it to the floor and that allowed the brakes to take hold. We made the turnoff at the end of the 11,000 ft. runway.

 

Edited January 9 by PT20J
Corrected typo on runway remaining edge lights from 1000 to 2000.

[Will.iam]

10 minutes ago, PT20J said:

Just don't carry it too far. I was once doing an IPC for someone in an Archer at SJC and we were asked to keep our speed up to the middle marker on the ILS 30L. Bob carried it a bit too far and crossed the threshold at 130 kts. As we progressed, I could see the 1000' remaining runway lights coming into view and the tower must have taken note also because they began calling out runway distance remaining. With less than 1000 ft. to go, when I was certain Bob would do the right thing and go around, he planted it on the runway and hit the brakes which caused an ineffective squealing fishtail. I reached for the flap lever and pushed it to the floor and that allowed the brakes to take hold. We made the turnoff at the end of the 11,000 ft. runway.

The end of the last white markers (or first set of white markers when you are nearing the end of the runway) is 3000ft remaining and i must be on the ground by then or i go around. On a 13,000ft runway that is forever. On the day i landed i settled down at the 8000ft board still had 5000ft of runway left. I never touched the brakes. 

[William Munney]

As may have been said, the speedbrakes  on the Mooney’s are parasitic drag devices, not flight spoilers.  At low angles of attack and high airspeeds they are effective with descents where you wish to keep the power up to prevent shock cooling without increasing airspeed because drag increases to the square of the airspeed.  I would say that decreasing airspeed as you enter the pattern from a cruise descent is another good use.

At high angles of attack and/ or low airspeeds they are ineffective.  They are designed to be so.  In fact, part of the certification of these speedbrakes on the airplane required them to produce no effect or very little ill effects during approach and landing if they failed extended or were inadvertently left in the extended position by pilots.  In this phase, high angles of attack, the speedbrakes “see” very little of the air over the wing so it spoils no lift and the small size of the brakes at the low approach speeds produces very little drag.

I read the approach speeds being mentioned here and they are too fast.  70-74 KIAS should cover every weight.  Any higher is wasted runway.  A stabilized approach at the proper airspeed is the key to landing ANY aircraft well.  This is a constant in aviation and works from Cessna 152 to Boeing 747.  Carrying extra speed for any reason other than gusty winds is not required and is not good technique.

Landing with the speedbrakes extended is definitely not needed and creates a hazard if you have to go around……especially into ice.  Larger airplanes, for example, automatically stow their speedbrakes/ spoilers as the power comes up for go-arounds or balked landings and all of them have some sort of aural alert for conditions where the speedbrakes are deployed and the thrust levers move forward.  The airplane is telling you “hey….pick thrust or drag…one or the other”.  In large aircraft, any time the speedbrakes are deployed a hand is kept on that lever to make sure they are stowed as soon as they are not needed.  They are a potential hazard if simply left deployed.  American Airlines crashed in South America years ago in an inadvertent flight into terrain scenario but would have cleared the mountain had the speedbrakes been stowed.  In fact, so close was the margin in that accident that they crashed on one side of the mountain top and the wreckage was found on the other side with the speedbrakes making all the difference.

I’m not sure how the speedbrakes on approach thing got into the Mooney community but i think it’s a bad idea all around.

Go around……will you remember it?  Engine failure…..will you remember it?  Descending through your assigned approach altitude at high rate…..will you remember it?  My opinion is use them if you need them but stow them if you don’t……and don’t try to fix landings with them.

Finally, deploying them on landing does nothing.  That’s not how they work.  You can produce as much drag by opening the door and pushing it out into the wind with one leg or sticking a gloved hand out the pilot window.  Ha ha  Ridiculous suggestions right?  But, only slightly more so than having the speedbrakes extended for the landing or using them as spoilers on the rollout.  My opinion only folks.

Edited January 11 by William Munney

[Schllc]

In theory, and with a very small probability, they could cause a real problem, but has it ever happened in a Mooney?  I do not know the answer. 
What I do know is that we are acutely aware of what we can see in the Mooney because it is less than 10’ from your face. The switch is exactly where your hand would be in any of those conditions, and the response is instant.  Failures are nearly all in the non deployed position because of the design.   Maybe losing a tool you use incorrectly could be a problem if it fails when you’re depending on it to be there, which is a whole other conversation. 
There has been a lot of discussion about safety and technique recently, which I would think is healthy.  Every option, feature, performance enhancer, or complication adds risk in a catastrophic failure but it’s usually mitigated with other benefits. It would have to, to make sense.  
I would never say speed brakes in a Mooney is inappropriate, much less a bad idea. 
They are a tool with a very specific purpose, and are completely optional.
Using a tool too often to mask other weaknesses is also probably not good.  
I used the speed brakes much less than I did the first year or two, which I attribute to other methods that I’ve adapted that are either faster, easier, or more efficient.  If you fly your plane often and listen to her, you will find it is very consistent in its reactions, and when you’re surprised it’s usually your mistake, so I don’t see how speed brakes is a negative.

I appreciate all the other perspectives even if I happen to disagree,  The rules are immutable and unforgiving, but the environment and our expertise is dynamic until we leave, I think I have to consider some of these things and experiment to see if there are places where I can improve.  
 

[LANCECASPER]

The two words "always" and "never" hardly ever apply.

[mike_elliott]

On 1/9/2024 at 12:45 PM, Hank said:

Tower turned me downwind at EPC about 6 nm out, then asked me to expedite my approach. Raised flaps and gear, advanced throttle and slowed down as I turned base, dropped gear on final, turned off a the 2nd exit, taxied forever to the FBO, and was halfway through unloading bags when the jet they were worried about became visible to me. Tower asked, I complied.   You think they'd learn, there were 40+ Mooneys there that weekend.

We taught the controllers about Mooney's that day for sure.

[aviatoreb]

Speed brakes are an invaluable tool when I am high like in the teens and atc is holding me high much longer than I would like then starts giving me descents that would otherwise put me too fast - its a great way for extended high fpm descent.

[EricJ]

12 hours ago, LANCECASPER said:

The two words "always" and "never" hardly ever apply.

I always say they never do.   

[MBDiagMan]

On 1/5/2024 at 4:02 PM, PT20J said:

Maybe because you need to retract the flaps sooner or later anyway, but the darn speed brakes seem failure prone and VERY expensive to repair? 

But seriously, the Precise Flight speed brakes aren't really spoilers -- they primarily increase parasitic drag, and as such they are most effective at higher speeds (drag is a function of TAS^2). If they had a big effect on lift they would be a problematic for go arounds.

I had understood from some reading long ago that they killed the lift on about 3 feet of the wing.  Wish I remember where I read that.  They do, however, obviously provide drag also or instead, or both.

[PT20J]

1 hour ago, MBDiagMan said:

I had understood from some reading long ago that they killed the lift on about 3 feet of the wing.  Wish I remember where I read that.  They do, however, obviously provide drag also or instead, or both.

They probably have some effect on lift, but not very much. Almost all the lift comes from the forward 25% of the wing chord (maybe a bit farther aft for a laminar flow airfoil). The brakes are mounted far aft on the wing. If they killed a lot of lift, you would feel a big sink when deploying them because lift would suddenly be less than weight and the airplane would accelerate downward.

[JohnB]

I like using speed brakes after touchdown if I want that earlier turnoff. (As well as the slam dunks and best speed approach requests by ATC as @donkaye mentions) as after touchdown, I think I can slow down a lot faster with speed brakes deployed and a little back pressure on the yoke, and keep my feet off of the brake pedals as long as possible, as caliper brakes and tires are very expensive and drag is free!

I try to save using foot controlled brakes until I get slow enough where speed brakes won't at all be effective, which I would think saves wear on tires and brake pads.  

[MBDiagMan]

When it comes to using the brakes, I find the Mooney brakes a little grabby compared to the Cleveland’s on my other plane.  I have to be careful not lock up a wheel when in the Moony.  Luckily I’m almost always on at least 6,000 feet in the Mooney so it’s not an issue unless I’m wanting to turn off the runway quickly.  
 

The next time I’m trying to make the next turnoff I will try to remember to deploy the brakes as I pull up the flaps.

[aviatoreb]

I have not made measurements - but my impression is that deploying speed brakes after touch down does just about zero.  So why bother and complicated the landing roll out.  Retracting flaps to put weight on the wheels does do a lot though.