Field Service Guide
Seal Replacement Procedure
Pitot – Static Test Adaptors
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August 16, 2017
-Replacement Seal Kit for applicable Test Adaptor
-Test Adaptor Outline Drawing (supplied with Seal Kit) showing seal location inside Test Adaptor or refer to Manual contained in Nav-Aids Ltd. Air Data Accessories Kit for applicable aircraft.
-Mild Cleaning Solvent (Chemsearch P/N SS25)
-NCS-30 Nonconductive Thread Compound, available from Jet-Lube of Canada Ltd. (Inventory Code: 16902).
-Clean work bench surface.
-Appropriate lighting to facilitate inspection of the interior of the applicable Test Adaptor.
-Compressed air (Optional)
-Pre-Test Tool for applicable Test Adaptor Lubricating Fluid P/N LF5050 (Nav-Aids Ltd.)
Note:For some Test Adaptors, glue is required to attach the new seal into the seat. Use Scotch-Weld 3M CA8 Sealant or equivalent.
|Seal Removal and Installation|
Seal Removal & Exchange Procedure:
1. Prior to disassembly of the Test Adaptor, prepare a clean bench surface for the layout of parts.
2. Refer to the supplied outline drawing of the Test Adaptor to identify and locate the seals.
3. Layout the new seals on the bench in a straight line and in sequence with the drawing (Ensure proper seal identification and sequence).
4. Remove the circlip under the knurled compression nut with the Awl (provided in the Tool Kit - Seal Exchange). Turn compression nut clockwise to ensure unobstructed removal of circlip. Insert Awl (Pin tool) into small holes to push circlip out of its seat.
5. Fully back off and remove the knurled compression nut by turning counter clockwise.
6. Carefully remove the seals and spacers from the interior of the test adaptor with the aid of the Extractor (provided in the Tool Kit - Seal Exchange). Place removed seals and spacers in sequence with the drawing and next to the new seals.
7. Inspect Spacers for condition (heat damage, distortion) and replace as necessary.
- Seal & Spacer kits are available from Nav-Aids Ltd.
8. Inspect the interior of the Test Adaptor for dirt, seal residue and corrosion.
9. Inspect the snubber at the Test Adaptor interior bottom for condition (Snubber for pitot tube tip protection). Note: A slit in the Snubber is normal.
10. Clean the Test Adaptor interior cavity with mild cleaning solvent and blow dry or use cotton swabs (provided in the Tool Kit - Seal Exchange).
11. Inspect the exterior of the Test Adaptor, fittings, labels, lanyards and flag for integrity.
12. Check compression nut, fittings and blanking caps for function.
13. Lubricate compression nut with Thread Compound, NCS-30 or equal lubricant.
14. Install the new seals as follows:
14.1. Pick-up first new seal (Seal located closest to the pitot tip snubber).
14.2. Insert the first seal into the Test Adaptor cavity and push the seal down to the full depth with the help of the Packer (provided in the Tool Kit - Seal Exchange).
14.3. Continue to identify and insert seals and spacers in the proper sequence as per drawing.
14.4. Ensure that seals and spacers are stacked tightly.
15. Install knurled compression nut with previously applied thread lube into Adaptor body.
16. Install circlip with the aid of the Golf Tee into its seat.
17. Verify that all components are assembled (discard old) and that the adaptor is working smoothly.
18. Verify Test Adaptor operation as follows:
18.1. Take the Pre-Test Tool and apply a thin film of Lubricating Fluid P/N LF5050 (2-3 drops) onto its test surface all around.
18.2. Insert the Pre-Test Tool fully into the Test Adaptor with a rotating motion and gently rotate it back and forth to lubricate the seals.
18.3. Tighten compression nut and connect the pitot and static test hoses on the Test Adaptor fittings.
18.4. Apply approximately 300 knots pitot pressure to the pitot line, and
18.5. 2000 feet static pressure to static connections of the Test Adaptor ( if applicable).
18.6. Check for leakage (For duration of leak test refer to applicable air data test procedures).
18.7. Release pitot and static pressure to ambient level.
19. If a leak exists in the pitot or static side, verify proper insertion of Pre-Test Tool into the adaptor and proper tightening of compression nut. If leak persists, verify proper seal and spacer sequence and installation.
For ease of installation of Test Adaptor on to aircraft pitot tube, use Lubricating Fluid (LF5050) with Pre-Test Tool prior to installation. (Ref: 18.1 to 18.2)
For our List of available Test Adaptors, Pre-Test Tools and Air Data Accessories Kits, you can consult our online catalogue (see bottom of page).
ForSeal Kits or Seal & Spacer Kits or for information to order replacement parts for this kit or for other types of aircraft, please contact us:
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