Thrust reverse...

[Archie Bunker]

I am looking for a pic or diagram of these.

Sliding cuff TRs was probably a poor choice of words on my part to describe the system.

From the Volume 2 (ops manual): The TR system on the MD-90 consists of cold-ducts (C-ducts), translating sleeves, blocker doors, and cascades. As the translating sleeve moves aft, it moves the blocker doors down and uncovers the cascades, which direct the flow of fan air outward and forward through the cascades. The doors are are shaped to fit together to form a complete barrier across the air duct and block the flow of air through the duct.

There....clear as mud?

Bottom line.....you're not going to drag a bucket on the MD-90 (because they didn't have any) like you could on the MD-88. Like I said, for the sake of standardization we (at Delta) didn't deploy the TRs on either aircraft until the NW was on the ground.

 

[Rez O. Lewshun]

Good info on the DC9 series....

Any thoughts on Boeing.. 757 or 747? How about airbus??

 

[gear_guy]

I used to fly with a guy in a Sabre 40 that deployed them in the flare on really short runways. Worked really well in that aircraft.

Exactly what do you think would happen if only one bucket opened while airborne?

Also 400A, in regards to "it depends on the runway length". Landing distance is not even including T/R's. So how could you justify an accident to the FAA if you lost directional control b/c you didnt have the nosewheel down.

Again, we are risk managers and I can't find a reason to take that risk.

 

[Donsa320]

Good info on the DC9 series....

Any thoughts on Boeing.. 757 or 747? How about airbus??

The A-320 requires the respective main gear squat switch to be compressed to get reverse...which is only cold stream anyway and not very effective. The DC-9 had no provision to prevent inflight reverse selection, just procedure. As to the reversers blocking the rudder some how, I say poppy cock. With about 15,000 landings in DC-9's in Northern Wisconsin, Michigan and Minnesota with wild crosswinds on icey runways I can assure anyone the rudder works just fine with lots of reverse applied. After the Little Rock accident American's school house came up with that lame excuse and the NTSB and Boeing bought it. If it had not been an MD-80 it would have departed the side of the runway long before the end with the technique that was used. No auto-brakes armed, no auto-spoilers armed and steering the ailerons like a car. ARG! Rant over.

 

[Beechjetr]

I saw a global express land in MTH once and the reversers were deployed almost coincident with touchdown. Do globals have auto-reversers? Someone told me they pull up the levers prior to touchdown and when the ground safe switches close they deploy??? Is this true?

 

[GravityHater]

There....clear as mud?

Thanks, still looking for a pic as I havent seen them up close b4.

 

[jergbsn]

This might be what your looking for??? Sorry for the length of the link.

http://www.airliners.net/open.file?...o_nr=3&prev_id=1135193&next_id=1133550&size=L

 

[GravityHater]

Thanks Jerg.

 

[Beechjetr]

V2500 not a JT8D right?

 

[MikeMD80]

As to the reversers blocking the rudder some how, I say poppy cock. With about 15,000 landings in DC-9's in Northern Wisconsin, Michigan and Minnesota with wild crosswinds on icey runways I can assure anyone the rudder works just fine with lots of reverse applied. After the Little Rock accident American's school house came up with that lame excuse and the NTSB and Boeing bought it. If it had not been an MD-80 it would have departed the side of the runway long before the end with the technique that was used. No auto-brakes armed, no auto-spoilers armed and steering the ailerons like a car. ARG! Rant over. [/quote]


I was made aware of the rudder "block out" by former Ozark drivers as well as instructors who had lots of time in type. It was not to say that the rudder became IN-effectve but LESS effective due to airflow being reduced by the buckets being deployed... Therefore the requirement for the nose to be on the ground before thrust reverse was applied. I'm certain AA came up with whatever excuse they could to detract from the pilots hosing up the landing in LIT. Trust me, I wouldn't take ANY info from AA's training center as something as knowledge. I worked for a company that was "acquired" by AA and I am aware of the the NUMEROUS problems/incidents AA had with flying the S80 during the last few years of shrinkage.... and it has not been pretty. I see that as a direct result of the training out of DFW.

By the way, that's quite a few landings in winter weather up in those parts....I would have hated to have your schedule!

 

[OPECJet]

I used to fly with a guy in a Sabre 40 that deployed them in the flare on really short runways. Worked really well in that aircraft. A no-no in the 60.

There are as many TR techiniques as there are aircraft. Use what works best for yours.

In the 2000, there is a sw on the nose gear, so it has to be down.

I've had only one bucket open on that airplane way too many times.......

 

[TXDA2000]

Exactly what do you think would happen if only one bucket opened while airborne?

quote]

Witnessed that as well, nothing shocking. On that particular airframe, they are close enough to the centerline, and the fuse is short enough, that one reverser deployed with no power equated to about one inch of rudder pedal.

 

[TXDA2000]

I've had only one bucket open on that airplane way too many times.......

Yea, probably more often than not! It's a good thing it is a non-event in the 40.

 

[Donsa320]

As to the reversers blocking the rudder some how, I say poppy cock. With about 15,000 landings in DC-9's in Northern Wisconsin, Michigan and Minnesota with wild crosswinds on icey runways I can assure anyone the rudder works just fine with lots of reverse applied. After the Little Rock accident American's school house came up with that lame excuse and the NTSB and Boeing bought it. If it had not been an MD-80 it would have departed the side of the runway long before the end with the technique that was used. No auto-brakes armed, no auto-spoilers armed and steering the ailerons like a car. ARG! Rant over.

By the way, that's quite a few landings in winter weather up in those parts....I would have hated to have your schedule! [/quote]

Yep, that was the way we operated DC-9's....20 minute legs all day long. Regarding the bucket deployment restriction on DC-9's, there was none until the MD-80 came along. When Douglas changed the bucket deployment on the -80 to a canted angle, the ground clearance was reduced enough to allow ground contact during deployment if the nose was up high enough. Their cure was to restrict deployment, by procedure, until the nosewheel was on the ground. That restriction is still in force but only on the MD-80 not the generic DC-9. If it is also so on the 717 it may be for other reasons.

Our distaste for AA's school house is obviously mutual.

DC

 

[Lead Sled]

Just a couple of thoughts and observations...
In the first few Astras the nosewheel squat switch had to be on the ground to be able to deploy the T/Rs. That was later removed and now they are capable of being deployed in flight. I flew an early G200 (Galaxy) and they also required the nosewheel squat switch to be on the ground - which made for some interesting moments if the guy in the right seat didn't hold forward pressure on the yoke during the initial portion of the rollout. (The T/Rs would deploy, then stow as the weight came off the nosewheel, then deploy again, then stow, then deploy...) They were talking about coming out with a service bulletin to move the T/R switch from the nosewheel to one of the main gears, but I havent flown a G200 for a few years and I don't know if it was ever done.

For us Part 91 (and 135) types, the AFM is pretty specific when it comes to the procedures and limitations on T/R usage. Stick with those and you won't run into many problems. Where you can run into problems is when pilots start to be "creative" in their thinking. If you are ever involved in a runway accident or incident and if you are using any techniques outside of those contained in the AFM you will end up having to explain to a fed and probably your insurance underwriter why your techniques are superior those contained in the AFM (and provide them with all of the supporting engineering and flight test data).

Remember the basics - T/Rs don't stop airplanes, brakes stop airplanes. T/Rs are more effective at high speeds, their effectiveness diminishes as your speed decreases. (I always thought T/Rs were a waste of money on 500 series Citations - by the time you got them deployed you were about ready to turn off of the runway. But they sure look cool.)

I've been flying jets for a long time and I can't honestly think of one instance where having the T/Rs made the operation safer or more "doable".

Personally, I'll deploy them, but I seldom if ever, get into them much beyond idle-deploy - it makes too much noise and rattles the back end of the airplane too much for my liking. So much for my personal technique.

LS

 

[Blackjet]

The CP at KC Life in kansas city had that happen in a BE40. 1 T/R deployed in flight and he managed to wrestle it back to the airport. I think he is 1 of 2 people to have had that happen to him in a BE40. I've been told the instructor at FSI (ICT????) tell that story during recurrent/initial. Super stud? I'd say so.

Exactly what do you think would happen if only one bucket opened while airborne?

Also 400A, in regards to "it depends on the runway length". Landing distance is not even including T/R's. So how could you justify an accident to the FAA if you lost directional control b/c you didnt have the nosewheel down.

Again, we are risk managers and I can't find a reason to take that risk.

 

[Archie Bunker]

V2500 not a JT8D right?

You are correct sir! The V2528-D5 high bypass ratio, twin spool turbofan International Aero engine rated at 28K pounds of take off thrust at sea level (4 barrel carb and dual exhaust optional)......a whole lot more giddy up than the standard P&W JT8D on the MD-88, rated at 21,700 lbs max takeoff thrust.

The difference was sort of like driving your Dad's '69 Chevelle with the 396, versus your Mom's '66 Dodge Dart with the slant 6.

 

[GravityHater]

and now they are capable of being deployed in flight.

Do we know what the flight characteristics of any of these a/c are, with reverse selected?
Brick attached to an anchor? Uncontrollable?

 

[Donsa320]

Do we know what the flight characteristics of any of these a/c are, with reverse selected?
Brick attached to an anchor? Uncontrollable?

I assume you mean only one in reverse. The MD-88, at least in the simulator, will shake badly if it occurs right after lift off with T.O. Flaps 11 degrees. Climb will be nil. Of course you shut down the reversed engine pronto. Then if you extend flaps to 15 degees the thing settles right down and will climb some. I think it is the slats going to full extend which changes everything. Of course if you are heavy and at Denver it would be dicey.
The Lauda Air 767 had it happen in cruise and they lost it. Why I do not know. Probably did not retard the power on the reversed engine and left the auto-pilot on too long. Those are cascade reversers on the 76 if I recall correctly so the thing should have flown with little trouble. I seem to recall that they were getting intermittent unlock warnmings and the Captain dismissed them as "not unusual".

 

[Lead Sled]

Do we know what the flight characteristics of any of these a/c are, with reverse selected?
Brick attached to an anchor? Uncontrollable?

There have been no in-flight deployments in an Astra (other than flight test) that I'm aware of. They say the sim is a pretty faithful replication - it's nothing that can't be handled by pulling back the power on the offending side. There was one dual deployment in a Westwind on short final going into ILG a few years ago. I know one of the pilots involved - he chooses not to repeat the experience. (He said that they're @#$% lucky to be alive.)

LS