Aero braking vs...

Hacker15e said:
That's nice, however it doesn't apply across all aircraft.

My current aircraft touches down about 140 knots, but has smallish tires and no anti-skid. Wheel braking is not effective in slowing the aircraft down above 100 knots, and will build up excess energy causing a hot brake condition.

Thus, if I don't aerobrake on landing (to slow from 140 to 100), I either:

- Blow the tires
- Have hot brakes
- Go off the end of the runway because of the stopping distance.

Here's what the T-38 manual says about normal landing:

But, hey...perhaps I should tell all those tens of thousands of pilots who have flown the T-38 that, according to the FAA, they're doing it wrong.
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In the 117 program, we flew both the T-38 as well as the Black jet. Both had completely different landing procedures vis-a-vis aerobraking. The T-38A was the same as described above (just no references to any kind of HUD), while the F-117....being a lifting body....was recommended to land and get the nosewheel down, for two reasons: One, it was very easy with that completely flat undersurface (lifting body surface) to get the aircraft airborne again at a very slow speed if the aerobraking was excessive, which wouldn't be good. Two, you had to have all three gear firm on the runway prior to deploying the drag chute, what with the severe jolt of drag it provided.

So different aircraft, different procedures. Like anything else, it depends.
 
Here's what the F-15E manual says about it:

3.16.1.4 Aerodynamic Braking. Aerodynamic braking is most effective above 90 knots and reduces the possibility of hot brakes while extending brake and tire life. After touchdown, on a full stop landing, cross-check airspeed to ensure the aircraft will not become airborne, then smoothly rotate the nose to establish approximately a 12- to 13-degree pitch attitude (reference the “whiskey” symbol [W] on the HUD pitch ladder). If the touchdown speed is fast, maintain the landing attitude until approximately 135 KCAS before initiating an aerobrake. Maintain 13 degrees or less until past the cable to prevent the cable from striking the tail. Use the rudder and ailerons to control your direction. Fly the nose down to the runway prior to 90 knots, with 100 knots as a good reference to begin.Once the nose is down, apply full aft stick for increased drag from the stabs and smoothly apply brakes.
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Hacker15e said:
Here's what the F-15E manual says about it:
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Good info. Forgot to add about the 117, that depending on fuel/ordnance weight, our touchdown speeds were oftentimes around 170-190, again weight dependant. Same mental math if one didn't have a cheat card with them. There was an aerobrake procedure, but it ate up alot of runway since, as previously stated, we couldn't aerobrake effectively at high speeds. The drag chute was primary, and if neither worked, there was the tailhook, but dropping that basically shut down that runway for quite a while....talking probably half a day.
 
MikeD said:
The drag chute was primary, and if neither worked, there was the tailhook, but dropping that basically shut down that runway for quite a while....talking probably half a day.
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Always wondered why an Air Force base had arresting wires. Although, I've gotten pretty good at touching down just past the darn things at VPS. First time I taxied over them for takeoff, I thought I blew a tire, though.
 
Great data, and I'd like to point out that instead of folks preaching about how their way is the best way, the professionals got out their manuals and started quoting language both explaining the reasoning for the procedure and how to implement it properly.

We need more of this around these parts.
 
Hacker15e said:
But, hey...perhaps I should tell all those tens of thousands of pilots who have flown the T-38 that, according to the FAA, they're doing it wrong.
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No one has said or suggested you are doing it wrong. You are right; every aircraft will have a different landing technique. The information the FAA puts out in the Airplane Flying Handbook is regarded as general information only and is superceded by any manufacturer's recommended procedure (and is generally geared more towards civil jet aircraft).

But thank you for sharing your information.
 
If you have beta also makes a huge difference. In the P3 aerodynamic braking is just plain useless compared to pulling those four big props into reverse.
 
I've seen Prowlers do it, after normal FCLP style landings no less, and it looked awkward to say the least. For the Hornet, it is not a good idea, as the rolling surface to rudder interconnect can give you some really weird transients (also why we don't forward slip landings in x-winds) if you need to make a lineup correction with the nose off the deck....or at least so I have been told by folks who have seen what happens. For normal ops, we plant it Navy style, tap the brakes at about 120-ish to make sure they work and to get the nose gear planted, aft stick below 100 kts to get full stab authority (our form of "aero braking") and then just normal brakes below 100 meeting line speeds on the roll out.

Anyway, interesting to see the differences among the various tacair procedures here
 
kellwolf said:
Always wondered why an Air Force base had arresting wires.
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It all has to do with brake failures or other emergencies where heavy fighters aren't able to stop on their own.

Here's one of my ex-Squadronmates trying an arrested landing at Lambert Field after a Utility A circuit hydraulic failure.

0256834.jpg
 
kellwolf said:
Always wondered why an Air Force base had arresting wires. Although, I've gotten pretty good at touching down just past the darn things at VPS. First time I taxied over them for takeoff, I thought I blew a tire, though.
Click to expand...

Most military and joint-use runways have two separate and different aircraft stopping systems: arresting gear, and aircraft barriers.

Arresting gear is designed to be engaged by tailhook-equipped aircraft and consists of a wire strung across the runway at various points and either supported by rubber "donuts" designed to keep the wire about 2 inches above the runway surface (that's the case with BAK-6/9/12 and13 or E-27/E-28 at USN/USMC bases), or recessed in a slot on the runway and raised by remote control as needed (BAK-14). When engaged by an aircraft, the wires run out and are connected at each end to a box on both sides of the runway that contains the stopping mechanism. The stopping mechanism consists of brake pads on a caliper that engage a rotor at a certain rate, stopping the aircraft; or a hydraulic "water squeezer" (on BAK-6) that engages a piston pushing against water inside a tube for "hydraulic" stopping ability. On the airport diagram, the arresting gear is depicted as a one-or two-way arrows near the approach, center, and/or departure ends of the runway. One-way arrows indicate single-direction arrestment, two-way arrows indicate bi-directional arrestment ability. See here where it's depicted:

http://204.108.4.16/d-tpp/1011/00162AD.PDF

Aircraft barriers are located at the departure ends of the runway and are designed to either "catch" the aircraft's wings, or it's main landing gear. Older systems, such as the MA-1A, consist of a approximately 6 inch high wire hooked to a 2-foot recessed net that lays flat on the runway. As the aircraft passes into the overrun, it's nosewheel runs over the 6-inch high wire causing the 2 foot high net to spring-up and engage the main landing gear of the aircraft, bringing it to a stop in the overrun. Newer barriers, such as the BAK-15, are raised by remote control from the tower and consist of a 23 foot high net supported by stanchions on each side of the runway, similiar to those emergency barriers aboard aircraft carriers, that catch the aircraft's wings as the aircraft passes through it, and stops the aircraft in the overrun. On the airport diagram, the barriers are depicted as a vvvv looking symbol at the end of the runway. On the diagram here, see the departure ends of runways 16 and 25.

http://204.108.4.16/d-tpp/1011/00007AD.PDF

Some military aircraft, such as the F-4, F-117, B-52, and some foreign versions of the F-16, still utilize drag chutes that are deployed on landing in order to shorten landing roll in normal ops, and as an abort aid for takeoff emergencies.

Other airports: ABQ has BAK-12/14, while TUS has BAK-12, BAK-12/14, and MA-1A MODified.
 
Hacker15e said:
It all has to do with brake failures or other emergencies where heavy fighters aren't able to stop on their own.

Here's one of my ex-Squadronmates trying an arrested landing at Lambert Field after a Utility A circuit hydraulic failure.
Click to expand...

Cool. So do all fighters (F16, 15, 22, etc) have the tailhook for these emergencies?
 
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