DOCUMENT TYPE AND REF. NO. TECHNICAL NEWS SHEET CT (Moth) No. 32 Issue 2
 
 
 

TITLE: FLIGHT LIMITATIONS

CLASSIFICATION MANDATORY

1. EFFECTIVITY.

All variants of DH60, DH80, DH82, DH83, DH85, DH87, Queen Bee and DH94 aircraft.

1. Results of a recent aircraft accident investigation have shown that the integrity of the aircraft wing structure had been severely compromised by the effects of:

• Glue Failure
• Fungal attack
• Wood shrinkage
• Chemical conversion/Oxidation of wooden structure caused by corrosion of metallic mating components
• Environmental conditions.
• Lack of drainage.
• Pre-existing damage

2. During the investigation it also became apparent that some inspection panels on the flying surfaces had been unintentionally deleted probably during previous fabric restoration or recovering. In addition and in order to facilitate full inspection of the wing structure, additional inspection panels are being introduced by Issue 2 of this TNS.

3. This Technical News Sheet (TNS) CT (Moth) No 32 Issue 2 prohibits any form of aerobatic or spinning manoeuvres on the following aircraft type:-

• DH94 Moth Minor

Note:

Due to the design and construction methods employed on the DH94 Moth Minor, there are currently no adequate inspection procedures available to justify the removal of the prohibition of aerobatic and spinning manoeuvres (introduced by TNS CT (Moth) No 32, Issue 1) on this type of aircraft.

4. This TNS CT (Moth).No 32 Issue 2 requires all operators of Moth aircraft to carry out:-

Detailed Visual Inspection of the wing, tail plane, fin, aileron, elevator and rudder structure internally for evidence of:

• Glue Failure/disbonding
• Fungal attack/Rot
• Wood shrinkage
• Water contamination/soakage
• Oil contamination/soakage
• Oxidation/Chemical conversion caused by corrosion of metallic mating components.
• Pre-existing damage (cracks, fractures, splits, bruising, warping/distortion, compression failures, crushing, hole elongation, etc.)
• Corrosion
• Woodworm, insect or bacterial attack
• Unacceptable wear and tear
• Deterioration of the internal protective finish
• Condition of the Rib stitching

and

the embodiment of structural Conditional Mandatory Modifications No 82, 83. 85, 89 onto the DH82A unless already embodied as required by TNS CT (Moth) No 5 if evidence of deterioration is found during inspection.

Note:

Conditional Mandatory Modifications No 82, 83, 85, and 89 were introduced via TNS CT (Moth) No 5 onto the DH82A aircraft as a result of structural inspections carried out (during W.W.II) on an aircraft which had accumulated significant service and exposure to climatic variation at that time. As most aircraft today have accumulated significantly more usage than aircraft in use during W.W.II, BAe strongly recommend the embodiment of Conditional Mandatory Modifications No 82, 83, 85 and 89 (as detailed by TNS CT (Moth) No 5) onto the DH82A, DH82C and Queen Bee regardless of the condition of the aircraft structure.

5. This TNS CT (Moth) No 32 Issue 2 supersedes TNS CT (Moth) No 32, Issue 1.

1. The instructions contained in this TNS CT (Moth) No 32 Issue 2 have been classified MANDATORY by the United Kingdom Civil Airworthiness Authority.

For aircraft requiring aerobatic and spinning clearance, the instructions contained in TNS CT(Moth) No 32 Issue 2 paragraphs 8A, 8C and 8D must be completed within 150 flying hours, 12 months or by the next annual inspection, whichever is the sooner, Paragraph 8B must be completed before the aircraft can resume aerobatic flight but no later than 150 flying hours, 12 months or by the next annual inspection, whichever is the sooner and from the date of issue of this Technical News Sheet at issue 2

For aircraft not requiring aerobatic or spinning clearance, paragraphs 8A, 8B, 8C and 8D must be completed within with 150 flying hours, 12 months or by the next annual inspection, whichever is the sooner.

Note:

Where the intent of the spar root inspection with bolts removed (paragraph 8B refers) has been carried out during restoration/overhaul work prior to the issue of TNS CT (Moth) No 32 Issue 2, and is substantiated by documented proof, compliance with paragraph 8B is not required.

2. Repeat applications of TNS CT (Moth) No 32, Issue 2 paragraph 8A must be carried out at intervals not exceeding 3 years.

The content of this TNS have been approved under the authority of the United Kingdom Civil Aviation Authority approval reference DAI/9402/92

• Relevant de Havilland Maintenance and Repair Manual (or equivalent)
• Civil Aviation Authority (CAA) Airworthiness Notice No 20 " Cotton, Linen and Synthetic Fabric-covered Aircraft"
• CAA Airworthiness Notice No 50 "Deterioration of Wooden Aircraft Structures"
• CAA Airworthiness Notice No 73 "Corrosion of Aircraft Structures"
• Civil Aviation Airworthiness Information Procedure (CAAIP) Leaflet 2-3 "Timber Conversion - Spruce"
• CAAIP Leaflet 2-8 "Fabric Covering"
• CAAIP Leaflet 2-9 "Doping"
• CAAIP Leaflet 6-1 "Inspection of Wooden Structures"
• CAAIP Leaflet 6-2 "Inspection of Metal Aircraft Structures"
• CAAIP Leaflet 6-4 "Repair of Metal Airframes"
• CAAIP Leaflet 6-5 "Rigging Checks on Aircraft"
• Civil Aviation Inspection Procedure (CAIP) BL/4-1 (Obsolescent) "Corrosion - Its Nature and Control"
• CAIP BL/4-2 (Obsolescent) "Corrosion - Removal and Rectification"
• CAIP BL/4-3 (Obsolescent) "Corrosion - Methods of Protection"
• CAIP BL/6-25 (Obsolescent) "Fabric Covering"
• CAIP BL/6-26 (Obsolescent) "Doping"
• Technical News Sheet CT (Moth) No 5 "Mandatory Modifications

Note:

The above CAA, CAIP and CAAIP referenced documents are attached. Further copies of the referenced CAA, CAIP and CAAIP documents may be obtained from:

6. PUBLICATIONS AFFECTED.

All aircraft except DH94 Moth Minor.

Aircraft Pilots Notes-

Remove hand amendment introduced by TNS CT (Moth) No 32, Issue 1.

DH94 Moth Minor.

Aircraft Pilots Notes-

Modify hand amendment introduced by TNS CT (Moth) No 32, Issue 1 to state that aerobatic and spinning manoeuvres are prohibited.

7. MATERIAL INFORMATION.

Woods 'Patent' Inspection Frame	Pt No 62268 (Alternate Pt No AGS 852 or,09-19200)
Fabric Patch 7" x 7" Spec (DTD 407 or equivalent)	Pt No 62269ND (Alternate Pt No 09-18750).
Drainage Eyelet	Pt No H19972 (Alternate Pt No AGS 840).

Note:

An alternate removable inspection panel or zip arrangement may be allowable in lieu of the 'Woods' patent inspection rings and patches on application, to the local airworthiness authority. Alternative modern material fabric patches may also be allowed if required in lieu of the patches detailed above on application to the local airworthiness authority

A. Structural Inspection.

1.Gain access to all areas of the flying surfaces of the aircraft. Reference should be made to the following figures for location and installation details:

Reinstate any inspection panels that may have been omitted or deleted subsequent to aircraft build.

2. Refer to Appendix 1 and CAAIP leaflets 6-1, 6-2 and 6-4. Using suitable light sources, mirrors, magnifying glasses, boroscopes, feeler gauges etc., carry out a Detailed Visual Inspection of the internal structure of all surfaces for evidence of:

• Glue Failure/disbonding. Fungal attack/Rot.
• Wood shrinkage.
• Water contamination/soakage.
• Oil contamination/soakage.
• Oxidation/Chemical conversion caused by corrosion of metallic mating components.
• Pre-existing damage (cracks, fractures, splits, bruising, warping/distortion, compression failures, crushing, hole elongation, etc.).
• Corrosion.
• Woodworm, insect or bacterial attack.
• Unacceptable wear and tear.
• Deterioration of the internal protective finish
• Condition of the Rib stitching

Pay particular attention to the following areas:

• Front and rear spars in the areas of ash doublers.
• Slat locking cable hole in both spars if applicable

Note: Some aircraft may have had the slats removed but the slat hole may still exist
• Spar root attachments.
• Interplane Strut attachments.
• Compression tube attachments.
• Slat hinges (if fitted).
• Leading edge ribs.
• Internal bracing wire attachments.
• Tip Bow attachments and Spar Tip tapers
• Rib joints
• Fin post and root attachments
• Control surface hinge attachments
• Base of rudder (especially steerable tailskid aircraft)

If any defects are found as a result of the inspection the appropriate conditional modification as detailed in paragraph 2.4 must be embodied on the DH82A (See also paragraph 2.4).
If similar defects are noted on other types of aircraft, an approved repair scheme should be installed.

Note 1:

Some spars are made from a block consisting of 19 laminations, others are of an 'I' section with an upper and lower capping section, extra vigilance for evidence of delamination must be taken where these types of spar are fitted.

Note 2:

Evidence gleaned from overhauls/rebuilds has shown that in some instances, glued joints may be intact in one position on a component but unsound a short distance away. Should glue line disbonding be found, the old glue must be removed completely and the surface of the timber refreshed by light sanding prior to re-gluing; where disbonding is evident on spars of laminated construction, the spar must be replaced. All repairs should be carried out in accordance with the relevant de Havilland Maintenance and Repair Manual (or equivalent).

B. Spar Root inspection.

1. At Spar Root attachments a bolt (and bush if fitted), should be removed from each spar and examined for evidence of corrosion. Examination of the spar timber within the bolt hole for evidence of oxidation (See appendix 1) should also be carried out. If damage is found, further disassembly to determine the extent of damage will be required.

2. Reinstall spar root bolt (and bush if required), using Zinc Chromate Jointing Compound and reprotect area.

C. Drainage Eyelet installation.

1. Refer to Figures 1 to 5 (dependant upon aircraft type) and ensure that the location and number of drainage eyelets in all flying surfaces correspond to the number and location detailed on the relevant diagrams.

2. Carry out a loose article inspection and restore fabric envelope in accordance with the relevant de Havilland Maintenance and Repair Manual (or equivalent), and CAAIP leaflets 2-8 and 2-9.

3. Carry out rigging checks if required in accordance with the relevant de Havilland Maintenance and Repair Manual (or equivalent), taking cognisance of CAAIP leaflet 6-5.

D. Labels.

1. Remove label(s) prohibiting aerobatic or spinning manoeuvres introduced by TNS CT (Moth) No 32, Issue 1

1. For all aircraft types except the DH94 Moth Minor, amend the recommended Maintenance Schedule to add the requirements of TNS CT(Moth) No 32 Issue 2 paragraph 3.2.

2. With the exception of the DH94 Moth Minor aircraft remove the hand amendment to the Aircraft Pilots Notes reflecting the prohibition of aerobatic and spinning manoeuvres (introduced by TNS CT (Moth) No 32, Issue 1) for the particular aircraft type.

3. For DH94 Moth Minor aircraft, the hand amendment introduced by TNS CT (Moth) No 32, Issue 1 should be amended to state that aerobatic and spinning manoeuvres are prohibited.

1. Record compliance with this TNS CT(Moth) No 32 Issue 2 together with the date and flying hours accomplished in the aircraft technical records.

Whenever a Technical News Sheet is issued or amended operators are required to hand amend the copy they hold of TNS CT(Moth) No 1 'Listing of Technical News Sheets' to ensure an up to-date index is maintained.

1. All damage must be rectified to an approved repair scheme. Damage which requires a repair outside the scope of the relevant Maintenance and Repair Manual may be repairable on submission of an appropriate repair scheme to the local airworthiness authority.

2. Report details of faults found or in cases where technical advice is required contact:-

Appendix 1 - Damage Identification

Fig1 DH60, DH82A, DH82C, DH83 and Queen Bee

Fig2 DH80

Fig3 DH85

Fig4 DH87

Fig5 Tailplane for all the above.

Fig6 Placard details