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AJGr33n

Over Torque Inspection

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G'day Everyone,

I have been looking at engine over torque inspection (for T56-A-15) but all our publications have very little information.

What I do have is 19,600 inlbs is max

23,260 inbls and above an over torque inspection is required. The only problem is well no where can I find anything writen as to what the inspection is.

Any one have any references / ideas as to what the inspection is meant to be.

Thanks in advance.

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Over torque inspection for your engine should be in your engine manual (ours is the NAVAIR 01-75GAA-2-4) .

Over torque inspection for the aircraft side is in the structures manual (ours is the NAVAIR 01-75GAA-3).

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Looked through everything we have both engine manual (which tells me nothing other then inspection required), Structural repair manual has nothing and engine Field Maintenance manual just tells me to check the mag plugs in the RGB which just doesn't seem enough.

I was thinking things like at least lord mount, Nacelle inspection and maybe trust mounts for a start.

I might have to try and dig up the NAVAIR and USAF publications.

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Your aircraft should have an inspection program. If you look for the Special Inspections or Structural Inspections, you should find one in there that references overtorque conditions and what the inspection items are.

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Field Maintenance manual just tells me to check the mag plugs in the RGB which just doesn't seem enough.

Thats about it for the power section (check mag pulg base on oil pressure and flux, next two flights) the aircraft side is the big inspection part.

NAVAIR 01-75GAA-3

9-52. DETAILED INSPECTION OF DAMAGE

AFTER AN ENGINE DEVELOPS AN OVERTORQUE

CONDITION.

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Concur with other posts - I'm currently trying to understand the consequence of a big overtorque (above 23,500 inlb) and so far my understanding is that it causes more stress to the airframe than the T56. Still seems odd that there's no upper limit though.

I do recall that the torquemeter inner shafts are calibrated to 29,550 inlb which is the number stamped on the exciter teeth - this is the torque required to twist the shaft through 6 degrees and is a calibration figure which I assume means that the shaft is actually flexed through it during manufacture - ergo must be able to withstand this torque without failure. Can anyone confirm that?

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Concur with other posts - I'm currently trying to understand the consequence of a big overtorque (above 23,500 inlb) and so far my understanding is that it causes more stress to the airframe than the T56. Still seems odd that there's no upper limit though.

I do recall that the torquemeter inner shafts are calibrated to 29,550 inlb which is the number stamped on the exciter teeth - this is the torque required to twist the shaft through 6 degrees and is a calibration figure which I assume means that the shaft is actually flexed through it during manufacture - ergo must be able to withstand this torque without failure. Can anyone confirm that?

The engine does not feel the over torque as the torque is transmitted to the wing structure. That is why the powerplant has very little inspection requirement. If the oil pressure is good and no flux the powerplant is fine.

The wing structure is what requires us to limit torque to 19,600. We can produce much higher values of torque but the structure cannot maintain its integrity above a certain value. To increase the power setting we need to increase the "strength" of the wing.

The J has limits (4,705 SHP) and is automatically controlled by the FADEC.

As for the Cal number on the torque shaft ALL of them are different... each shaft has the actual number stamped on it that represents the torque required to twist the shaft through 6 degrees(or 19,600) so each one is tested to get the exact number, but we use a common number to make things easier. Cal to +/- 50 inlbs so...

The shaft can withstand much higher torque values than the stamped number...

I have seen a torque value above the gage (gauge) scale....

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Maybe this will help!

04132 A. AFTER AN ENGINE OVER TORQUE EXCEEDING 19600 BUT NOT MORE THAN 21500

INCH POUNDS, ENTER OVER TORQUE IN QEC, ENGINE, AND AIRFRAME AFTO FORM

95 FOR HISTORICAL PURPOSES. 005

B. WITHIN 25 AIRFRAME HOURS AFTER AN ENGINE OVER TORQUE EXCEEDING 21500

BUT NOT MORE THAN 23000 IN-LBS., INSPECT THE FOLLOWING QEC, NACELLE AND

SUPPORT STRUCTURE FOR CONDITIONS NOTED(SEE TO 1C-130H-2-70FI-00-1-2 FOR

ADDITIONAL REQUIREMENTS.) AFTO FORM 95 ENTRY REQUIRED.

11540 (1) QEC UPPER AND LOWER LONGERONS AND FASTENERS ATTACHING UPPER

LONGERON TO FIREWALL FOR CRACKS (190) AND LOOSE OR MISSING (105)

FASTENERS. 020

11540 (2) PART NO. 362522 QEC BEAM FOR CRACKS (190). 015

11540 (3) QEC DIAGONAL BRACE FOR CRACKS (190). 010

11540 (4) DISCONNECT FITTINGS IN AFT END OF QEC FOR CRACKS (190), ALIGNMENT (127),

AND SECURITY (730). 010

11540 (5) TRUSS MOUNT LONGERONS, DIAGONALS AND SWAY BRACE AND ATTACHMENT TO

FRONT BEAM FOR CRACKS (190) AND LOOSE OR MISSING (105) FASTENERS. 030

0411B (6) PERFORM NDI OF THE UPPER TRUSS MOUNT VERTICAL LEGS (1154Z) AND TANGS

(1154Y) IAW TO 1C-130A-36, N-11. (APPLICABLE TO OVER TORQUES ON #1 AND #4

ENGINES ONLY). REMOVAL OF ENGINE IS NOT REQUIRED. 030

0411B (7) PERFORM NDI OF WING LOWER SURFACE PANELS (UNDER NACELLE FAIRING

ATTACH ANGLES) AND ENGINE DRAG FITTINGS (11540) IAW TO 1C-130A-36, CW-23 OR

OW-47 AS APPLICABLE. 015

11540 (8) VISUALLY INSPECT NACELLE FAIRING ATTACH ANGLES FOR LOOSE OR MISSING (105)

FASTENERS. REF TO 1C-130A-36, CW-23 OR OW-47. 005

11540 (9) NACELLE SKINS AND FAIRING FOR BUCKLES (780) AND LOOSE OR MISSING (105)

FASTENERS. 045

11550

11580(10) PERFORM A THOROUGH VISUAL INSPECTION OF THE IR HEAT SHIELD LOWER TUB

AND UPPER TRACK ASSEMBLIES FOR EVIDENCE OF BUCKLES (780) AND LOOSE OR

MISSING (105) FASTENERS. 045

C. ENGINE OVER TORQUE EXCEEDING 23000 IN-LBS. (FOR AIRCRAFT AT LOCATIONS

WHERE NDI CAPABILITY DOES NOT EXIST, THE NDI REQUIREMENTS WILL BE

ACCOMPLISHED AT THE FIRST FACILITY WITH NDI CAPABILITY, NOT TO EXCEED 25

AIRFRAME HOURS) SEE TO 1C-130H-2-70FI-00-1-2 FOR ADDITIONAL REQUIREMENTS.

AFTO FORM 95 ENTRY REQUIRED.

(1) ACCOMPLISH ALL ITEMS LISTED UNDER PARAGRAPH 4.B. ABOVE.

(2) NDI THE FOLLOWING STRUCTURE FOR THE CONDITIONS NOTED. THE POWER PLANT

MAY REMAIN INSTALLED.

0411B (a) PERFORM NDI OF ENGINE TRUSS MOUNT SWAY BRACE ATTACH LUGS (1154Y) IAW TO

1C-130A-36, N-9. 015

0411B (B) PERFORM NDI OF FORWARD OR FORWARD UPPER (AS APPLICABLE) BOLT HOLES OF

ENGINE TRUSS MOUNT UPPER TANGS (1154Y) IAW TO 1C-130A-36, N-10, SCANS 13 OR

15 AND 8 OR 18 AS APPLICABLE. NDI BOLTS BY MAGNETIC PARTICLE TEST BEFORE

REINSTALLATION. 015

(3) WITH THE ENGINE IN A NO-LOAD CONDITION, CHECK THE FOLLOWING BOLTS FOR

MINIMUM TORQUE IN THE TIGHTENING DIRECTION. IF BELOW MINIMUM TORQUE,

REMOVE AND REPLACE WITH NEW BOLTS OR REMOVE, NDI AND REPLACE THE

FOLLOWING BOLTS:

1154P (a) UPPER QEC AFT ATTACHING BOLTS, 3700 IN-LBS (FOR AIRCRAFT WITH TCTO 1C-130-

1340 COMPLIED WITH MINIMUM TORQUE FOR #2 & #3 UPPER ATTACH BOLTS IS 4800

IN-LBS). 005

1154Q (B) LOWER QEC AFT ATTACHING BOLTS, 2300 IN-LBS. 005

1154M (4) WITH THE ENGINE IN A NO-LOAD CONDITION (REF TO 1C-130H-2-71JG-00-2, 71-20-10),

CHECK MINIMUM TORQUE ON THE FRONT ENGINE MOUNTS (LORD MOUNT)

ATTACHING BOLTS. IF THE TORQUE IS LESS THAN 400 IN-LBS IN THE TIGHTENING

DIRECTION, REMOVE AND REPLACE FRONT ENGINE MOUNTS (LORD MOUNTS). TAG

FOR OVERHAUL IAW TO 2RA3-2-3: 060

1154M (5) IF THE RUBBER OF THE FRONT ENGINE MOUNT HAS FLEX CRACKS WHICH HAVE

PROGRESSED INWARDLY TO A DEPTH OF ¼ INCH. REMOVE AND REPLACE FRONT

ENGINE MOUNTS (LORD MOUNTS). TAG FOR OVERHAUL IAW TO 2RA3-2-3:

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Thanks bischoffm and others

That's probably the most comprehensive inspection I've seen. I have a similar task card here which outlines much the same inspection requirement for the airframe in the 19600 to 23000 inlb but for 23000+ it's just the same inspection with results forwarded to Lockheed Martin. I note your title reflects this is from the A6, which I'm unfamiliar with but assume it's attached to an older C130 airframe (A model maybe?). I'm looking at the H model, no idea what the airframe structural differences are (as you may have gathered I'm an engines man).

General gist of everything I've read here is that the engine is not going to fail from overtorque. I had wondered where in the drivetrain from turbine to prop it would break - somethings got to give eventually - but I guess that as long as the airframe is expected to start failing somewhere around 23000 inlb and the engine (or torquemeter at least) is good for at least 30,000 then there's no point pursuing it.

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Cancel previous - just looked closer at reply and noted references to TO 1C-130A-36 so answers my question about which airframe was used.

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Thanks bischoffm and others

That's probably the most comprehensive inspection I've seen. I have a similar task card here which outlines much the same inspection requirement for the airframe in the 19600 to 23000 inlb but for 23000+ it's just the same inspection with results forwarded to Lockheed Martin. I note your title reflects this is from the A6, which I'm unfamiliar with but assume it's attached to an older C130 airframe (A model maybe?). I'm looking at the H model, no idea what the airframe structural differences are (as you may have gathered I'm an engines man).

General gist of everything I've read here is that the engine is not going to fail from overtorque. I had wondered where in the drivetrain from turbine to prop it would break - somethings got to give eventually - but I guess that as long as the airframe is expected to start failing somewhere around 23000 inlb and the engine (or torquemeter at least) is good for at least 30,000 then there's no point pursuing it.

The A-6 is used for ALL C-130's except for some specialtiy and the J model they have there own. It covers and is used on the C-130H aircraft.

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NATOPS1,

I liked your picture of the Torque and Reference shaft, with the 6.04 degree twist at 19.6. Can you possibly provide a source for that document

Thanks Ron

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This picture is out of an OLD USMC training Doc (out of publication) but I'm pretty sure it mirrors the Lockheed Training Manuals that were printed years ago.

The Navy version has Blue covers and the Marine Corps has Red (Scarlet).

There are electronic versions out there...

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