DG Flugzeugbau GmbH 76646 Bruchsal Subject Effectivity

Accomplishment

Reason

[nstructions

Material

Weight and ba lance Remarks

nruchsal , date : 30.08.2011 Author: W. Dir ks 

### Technical note**No~** 

### 500/04 Bulkheads of the C.G. tow hook page I from 1

Instructions 1 and 2: DG-500 all variants (sailplanes and motorglidcrs) , all ser. No.'s. Instruction 3: Ser. No.'s 5EI up to 5E23**In~1ruction** 1 : Prior to next winch launch Instructi ons 2 and 3: Mandatory lat est March 31.2012 Damage ofthe bulkheads of the C.G. tow hook and their glued joints to the fuselage shell has been reported. This damage may be due to a wheel up landing. If this damage is not de tected, the glued joint may later fai I completely during a winch launch. To overcome this potential loss of safety the bulkheads must be reinforced to minimize the risk ofdamage after a wheel up landing. I. Check the bu lkheads of the C. G

. tow hook according t o working instruction No. 1 tor TN500/04. In case of damage instruction 2 must be perf o rmed immediately. 2. Reinforce the bulkheads of the C.G. tow hook according to working instruction No. 1 for TN500/ 04. 3. Ser. No. 's 5El up to 5E23: exchange the C. G. tow hook access cover. Working instr uction No. 1 for TN5 00/04 2 GFRP

- reinforcement plates 5R308 Scr. No.'s 5El up to 5.£23: tow hook access cover 5RU32/7 E poxy resin/hardener Momcntive EPIKOTE TM Resin MGS LR 285 with EPIKURE TM Curing /\gent MGS LH 286 Cotton flocks Glasfibre fabric Interglas 92140 FK144 influence negl i gib le Instruction No. I may be executed by the pilot/owner himself and is to be inspected and entered in the aircraft logs by a licensed in s pector at the latest with the next annual inspection. Instructions No.2 and 3: I. EASA co untries: The actions have to be performed in a Part -145 approved organisation, or in a Part M, Subpart F approved organisation according to the regulations of the Part M and re leased according to M.A.80 I

. 2. Non EASA countries: The actions have to be performed in a licensed workshop. All instructions are to be inspected and entered in the aircraft logs by a licensed inspector.

Modifications approved by EASA Date 22.09.20 II under Approval No. 10036611

### DG Flugzeugbau Working instruction No. l for 1N500/04 Seite 1 

### von2 Reinforcement of the bulkheads of the C.G. tow hook 1) 

### Remove the height adjustable rear seat shell. 

### 2) Remove 

### the tow hook 

### access cover. . 3) Check ifthe bulkheads of the C.G. tow hook (5RU44/45) or their glued joints to the fuselage she ll are damaged. Ifthis is the case repa ir (glassfibre fabric 3 x 92140) or exchange the bulkheads. 4) 

### The bulkheads of the C.G. tow hook shall be reinforced with GFRP-rei.nforcement plates 5R308, 8 mm thick. To accomplish this roughen the areas D at the bulkheads and the fuse lage shell area 

### E between the bulkheads with abrasive paper 60 grit, areas**se~**

### sketc~ I. Don ' t damage the tow hook! Remove any excess glue resin at the

### glue**'!)** ofthe bulkheads to the fuselage as far as possible.

### ~ !

# ~

# ~

E

0



### Sketch 1

# ~**D~' ~~''U**  5) Roughen all**surfaces~~** 

### GFRP-reinforcement plates 

### F and scarf the contact surface of the**pia~ ~** 

### step-up ofthe bulkheads according to sketch 2. If the excess glue resin (see

### it~ •.

### ~ouldn't be removed sufficiently, scarf the GFRP plates accordingly.**~\0tlre** 

### plates at the lower i·ear end to match the recess ofthe fuselage shell in**fr~1t** 

### (011e tow hook. 6) Ser..**~~~~up** 

### to 5E23: Ifthe GFRP-reinforcement plates F interfere with the**rec:_~ ~~**  

### main bulkhead for the tow hook access cover, grind matchjng cut outs into**~ss.** 

### ·

# ~ I

F Schaftungl 

### scarf**------ ----** **----- ·** 



### Sketch 2

Issued: 30.08.2011DG Flugzeugbau Working instruction No. 1 for TN500/04 Seite 2 von 2 Reinforcement of the bulkheads of the C.G. tow hook



# F

---__

I Sketch 3 only tow-hook Bulkhead with GFRP-plate 

### F shown (_ 

### --·· - - --- - - - --··"'"'" 

### ·- · . .......... .. ...

## ~-**-- --** **----·- ·----** **-- ~** **::.::--: .:~---·** **""** - -- -- - 7) Preparing the reinforcement glasfibre fabric G: Mix Epoxy- re sin/hardener Momentive EPlKOTE TM Resin MGS LR 285 with EPIKURE 

### TM C uring Agent MGS 

### LH 286 (mixing ratio 100:40 by weight). Laminate 3 layers of Interglas 92140, ±45° on a plastic foil. Cut exactly according to sketch 4. 64

Sketch 4 202

# ~ FlugrichtunW, dlrectlon of fl1ght

8) Apply the resin/hardener mix (see item 7) to all gluing surfaces. 9) Thicken the resin/hardener mix with cotton-flocks and apply t his mix to the g lui ng smfaces of the GFRP-plates. 10) Place the GFRP-plates to the bulkheads and press. Apply the pre-laminated reinforc ement glasfibre fabric G according to sketch 5. 11) Let cure at room temperature 12) Post cure this fuselage section at min. 54° C for 18 hours. 13) Sand off excess glasfibre

. fabric. 14)From ser. no . 

### 5E24 on : reinstall the tow hook access cover Ser

. no. 

### 5El + 

### 5E23: Trim the new tow hook access cover 5RU32/7, drill the holes and install. 

### 15) Reinstal l the height adjustable rear seat shel l.

Issued: 30.08.2011