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tinyclark

Cargo door

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Given the fact that there may be aircraft out there where the door will free fall and lock, is there anything in writing that requires it to do so? We can find nothing in any book that requires it to do so. All checks we perform and any mention of it in the -1 requires the switch to be set to the down position, which will lock this particular door.

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In the E model we used to actually hold the door open switch and release the door from the uplock using the manual release lever with the other hand and then let the door free fall closed. In the H, we use the door close switch to get it out of the uplock and then let it free fall. Either way, once the door is released from the uplock it will free fall to the locked position. The only time I have had to use the door close switch to get the door to actually lock closed is in flight when the airstream holds the door open. That rarely happens. The door does not lock electronically. It locks through a simple system of metal wires and pulleys. Climb on up there and look at it sometime. It is really simple mechanics and 50s technology!

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The weight of the door is enough to lock it on the ground, usually. In the air sometimes the airflow will push up on it enough to keep it open. Check the 52 series, it should have all the info in there.

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It isn't locking in flight, works fine on the ground. The 52 series all say to go to close position.

I am looking for something in writing that says it must lock after free fall in flight. I don't care if 98% of them do it. If it isn't in black and white, it isn't a requirement.

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If you're doing JPADS, or other high altitude airdrop, they do occasionally have a tendancy to "hover" slightly open at altitude when the engineer attempts to close the ramp and door from up front. As a Loadmaster, we may have to go up and stomp on one side or the other to get it to lock closed. It is required in the -1 to have a closed ramp and door in order to pressurize the airplane. Not having the ramp and door locked also limits our airspeed as well.

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Even on the ground, the aft cargo door is not required to be able to free fall down and lock.

From a JG that I have:

Using auxiliary hydraulic system handpump (3), apply hydraulic pressure.

RESULT: On airplanes AF72-1288 and up, aft cargo door fully closes and locks at a pressure less than 1,000 psi. On airplanes prior to AF72-1288, aft cargo door fully closes and locks at a pressure less than 1,500 psi.

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If you're doing JPADS, or other high altitude airdrop, they do occasionally have a tendancy to "hover" slightly open at altitude when the engineer attempts to close the ramp and door from up front. As a Loadmaster, we may have to go up and stomp on one side or the other to get it to lock closed. It is required in the -1 to have a closed ramp and door in order to pressurize the airplane. Not having the ramp and door locked also limits our airspeed as well.

I think you are misunderstanding me. It does lock if you hit the switch to close, up front or in the back.

There is no reason you should have to stand on it. If you have to do that, then something is wrong, as the actuator should apply enough pressure to get it to lock.

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Tiny,

Is the door not locking when you free fall it in flight or on the ground? I don't remember any time we would free fall the door in flight, the engineer would close it up front. I don't know anywhere it is written that the door has to free fall but all ways did on the ground. Of course it has been many a year since I had the pleasure of working on the plane. The only job that I ever loved.

Smitty

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Tiny, all I can suggest is check out the -6CF for the applicable type Herk your dealing with.

Many, many oddball requirements, limitations and mandatory human sacrifices will be found there and nowhere else.

But I cannot foresee any requirement for a cargo door to freefall to lock in-flight, honestly it just aint going to happen outside of a freak thing

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I haven’t got “yet” any reference in our books stated that the door will free fall and lock during flight or ground; in the contrary:

Quoting:

The cargo door is closed by holding the DOOR control switch to the CLOSE position until the door is closed and locked.

Note

In the event the cargo door is released from the uplock by the cargo door uplock release, the door should be allowed to free fall closed and the auxiliary system hand pump used to close and lock the door.

Ref. FM 382C-14E (H model) under “Normal Operation of Cargo Door and Ramp” section 2 page 175.

Yes, during ground operation “most of the time but not all” it will free fall and travel all the way to the closed and lock position.

During flight, normally we are using the hydraulic pressure (3000psi) to close it, although sometimes it fails to lock (ram air resistance) unless forced by “weight”.

Is it door weight issue?

Are the auxiliary loading ramps or other items kept on the door stowage provision play a role on this issue?

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Is it door weight issue?

Are the auxiliary loading ramps or other items kept on the door stowage provision play a role on this issue?

The extra weight in the door should help the issue, not hurt it.

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That what I was aiming to; “heavy easy to lock, light may not lock”, (if we disregard the effect of other faulty factors such as down lock assembly, snubber, shuttle valve, and pressure reducer if system is equipped with).

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With no elec. or hyd. power on the acft. and the aft door open, ramp down , does anyone remember releasing the door manualy with the C/C valves set so the ramp would come up part way? Sure beat hand pumping the ramp up.

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With no elec. or hyd. power on the acft. and the aft door open, ramp down , does anyone remember releasing the door manualy with the C/C valves set so the ramp would come up part way? Sure beat hand pumping the ramp up.

Yep, did it more than a few times, it didn't really pull the ramp up a whole bunch but when your pumping that sucker any little bit helps

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Yep, did it more than a few times, it didn't really pull the ramp up a whole bunch but when your pumping that sucker any little bit helps

We normally get it to come up to about a foot short of being closed. Though in saying that, the ramps and such haven't been loaded into the door yet.

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I think this question is much like the free fall of the MLG during emergency extension. An emergency extension of the MLG on a ground test may result in the gear free falling down to their stops. This is awful nice but not required by the TO. Many have come to the conclusion that they must freefall to pass the check but it is not so, but has become to be expected.

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I think this question is much like the free fall of the MLG during emergency extension. An emergency extension of the MLG on a ground test may result in the gear free falling down to their stops. This is awful nice but not required by the TO. Many have come to the conclusion that they must freefall to pass the check but it is not so, but has become to be expected.

That sounds like piss poor training to me.

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That sounds like piss poor training to me.

Actually, it is more like lack of training. Not everybody has the opportunity to attend a course that covers operational checks of the landing gear extension and retractions system, and they don't bother to read the technical orders until they really have to. People just "assume" that they know how things should be.

I've seen some really great mechanics who can normally figure out complex problems who will become stuck on an issue merely because they don't read enough.

The beloved FAA has approached this problem in their regulations. They do not allow an A&P to perform a task unless the A&P has been taught how to do that task. In short, mechanics are technically not permitted to "figure out" how to do a task; they must be trained first. I guess the FAA knows that many mechanics won't read.

The funny part is that A&P's also assume that their license means that they can work on any aircraft they choose and do any job they want. The truth is that the A&P is merely a license to learn.

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to attend a course that covers operational checks of the landing gear extension and retractions system.

Please tell me this is not a separate class, but apart of general hydraulics school and/or an aircraft fam school? Or I will be laughing my ass off at the stupidity of the Air Farce yet again....

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We had a saying, "when all else fails read the TO".

Comparing civil aviation A&P techs with blue suit techs is like comparing apples and oranges. The same can be said of the equipment they maintain. In many instances, civilian A&P techs unlike AF techs, work on airplanes until they retire. How often have you seen a white haired AF tech bending a wrench, (except in Guard/Reserve units)? I was part of an AF DT&E flight test team working with contractor techs, the oldest of whom was 64 years old. I'll never forget watching this old geezer climbing a tall maintenance stand to r & r a top of the vertical fin anti-collision light. This old boy told me he had been working on acft. since he was 17 in the Army Air Corps. I remember turning in my tool box when I made MSgt at 36. Further, the difference in qualifications/experience can be seen in civil tech data compared to AF tech data. Whereas civil tech data is general in nature, AF tech data is very detailed. Writing AF tech data could be difficult as the tasks had to be written at the 8Th grade level. Remember getting new troops fresh from tech school who still didn't know the difference between a box end and an open end wrench. In fairness to the young troops, tech training in the AF is, for the most part, nonexistent. After very basic five or six week initial tech school, and later, if your lucky, you may get to attend an FTD or two. Oh, almost forgot the 7 level training at Sheppard where AETC crams one week of training into two.

Sorry, after reading all the posts on this thread mine is kind of off topic. Will try to do better next time.

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Bob, In those days when I was about 40, yea, I thought 64 was a geezer. These days, however, I am that geezer. In fact I could be considered a geezer/1c. :D

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For what it is worth, and you "older gentlemen" already know, it used to be the Aero Repair and hydraulics was a separate responsibility area. AR schools taught electrics, hydraulics, and mechanical systems that we required to work doors, flight controls, and landing gear. However, I've been out for 20 years now, and I've been told that all that has changed.

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