SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page TS-1 of TS-1 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

TRANSMITTAL SHEET

Original issue 

This page transmits Original issue of Service Bulletin No. ATR42-55-0014. 

General information concerning this document is available in Service Letter No. ATR42-00-5005. 

TITLE: Stabilizers - LH and RH elevators - Inboard hinge fittings - Inspection of lower 

stop fitting angles 

1 – TABLE OF CONTENTS 

TRANSMITTAL SHEET ...................................................................................Page TS-1 to TS-1 

ACCOMPLISHMENT REPORT ...................................................................... Page AR-1 to AR-2 

PLANNING INFORMATION............................................................................... Page PI-1 to PI-5 

MATERIAL INFORMATION.............................................................................. Page MI-1 to MI-2 

ACCOMPLISHMENT INSTRUCTIONS ............................................................. Page AI-1 to AI-7 

ILLUSTRATIONS................................................................................................ Page IL-1 to IL-2 

2 – REVISION SEQUENCES 

Issue or Revision Date Additional work 

 

Original issue May 11/10 - 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AR-1 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

ACCOMPLISHMENT REPORT 

SERVICE BULLETIN No. ATR42-55-0014 

Original issue 

Send this report to: 

ATR ENGINEERING 

SERVICE BULLETIN GROUP 

1 ALLEE PIERRE NADOT 

31712 BLAGNAC CEDEX 

FRANCE 

phone : +33 (0)5 62 21 62 21 

fax : +33 (0)5 62 21 69 41 

e-mail : techdesk@atr.fr 

Aircraft identification

Service Bulletin accomplished on aircraft MSN: 

Service Bulletin accomplishment date: 

Aircraft registration number: 

Number of flights: 

Flight hours: 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AR-2 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

Inspection results

Tick (3) the appropriate box 

 Item 1 Item 2 Remarks 

Which damaged angles have you found on 

the LH side elevator? 

 

Which damaged angles have you found on 

the RH side elevator? 

 

 

Performed actions 

Maintenance organisation identification

Maintenance organisation name: 

Name & Signature: 

Date: 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

Page PI-1 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

COMPLIANCE: MANDATORY INSPECTION: 002/2010 

TITLE: Stabilizers - LH and RH elevators - Inboard hinge fittings - Inspection of lower 

stop fitting angles 

1. PLANNING INFORMATION

A. EFFECTIVITY

(1) Aircraft models 

ATR42-200 ATR42-300 ATR42-320 ATR42-400 ATR42-500 

YES YES YES YES YES 

(2) Aircraft 

MSN Kit(s) 

003, 004, 005, 006, 007, 009, 010, 011, 013, 

014, 015, 016, 018, 019, 020, 021, 022, 023, 

024, 025, 027, 030, 031, 032, 033, 035, 036, 

038, 039, 041, 042, 043, 044, 045, 047, 049, 

050, 051, 052, 053, 054, 055, 057, 058, 059, 

060, 061, 062, 063, 064, 066, 067, 068, 069, 

070, 072, 075, 078, 079, 080, 081, 082, 085, 

086, 087, 088, 089, 090, 091, 092, 093, 095, 

096, 097, 102, 103, 104, 106, 107, 109, 110, 

112, 113, 115, 116, 117, 118, 119, 120, 121, 

122, 123, 125, 128, 130, 131, 132, 133, 134, 

135, 136, 137, 138, 139, 141, 142, 143, 148, 

149, 151, 152, 155, 158, 159, 161, 165, 166, 

169, 170, 172, 173, 176, 178, 179, 182, 187, 

188, 190, 191, 193, 194, 196, 197, 199, 200, 

202, 203, 205, 206, 208, 209, 211, 213, 214, 

None 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

Page PI-2 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

MSN (continued) Kit(s) 

216, 218, 219, 221, 225, 226, 228, 230, 231, 

233, 235, 236, 238, 240, 242, 243, 245, 247, 

250, 252, 254, 255, 257, 262, 264, 266, 268, 

269, 273, 275, 277, 278, 280, 282, 284, 286, 

287, 289, 291, 293, 295, 296, 298, 300, 304, 

306, 308, 310, 312, 314, 315, 317, 319, 321, 

323, 325, 327, 329, 331, 333, 335, 337, 340, 

343, 346, 348, 351, 354, 356, 358, 360, 363, 

366, 368, 371, 374, 376, 378, 380, 382, 384, 

386, 388, 390, 392, 394, 397, 400, 403, 406, 

409, 412, 415, 443, 445, 457, 462, 466, 471, 

474, 476, 480, 484, 487, 490, 491, 495, 497, 

500, 501, 502, 503, 504, 506, 507, 510, 511, 

512, 513, 514, 515, 516, 518, 520, 522, 524, 

526, 528, 530, 532, 534, 537, 539, 542, 544, 

546, 549, 551, 554, 556, 559, 561, 564, 566, 

569, 571, 574, 576, 579, 581, 584, 586, 589, 

591, 594, 596, 599, 601, 602, 603, 604, 605, 

606, 607, 608, 609, 610, 611, 612, 613, 614, 

615, 616, 617, 618, 619, 620, 621, 622, 623, 

625, 627, 629, 631, 633, 635, 637, 639, 641, 

643, 645, 647, 649, 651, 653, 655, 657, 659, 

661, 663, 665, 667, 669, 671, 673, 675, 689, 

691, 693, 695, 800, 801, 802, 803, 804, 807, 

815 

None 

(3) Spares 

The following stock items are modifiable (or not) according to the table below. 

None. 

B. REASON

At level of LH and RH side elevator front spars, some inner and/or outer angles of the 

lower stop fitting installed on inboard hinge fittings have been found cracked on several 

aircraft. 

This Service Bulletin consists in inspecting these angles and in replacing them if 

necessary. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

Page PI-3 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

COMPLIANCE: Accomplishment of this Service Bulletin is mandatory. 

An Airworthiness Directive will be issued by EASA. 

C. DESCRIPTION

Accomplishment of this Service Bulletin consists in carrying out the following jobs: 

(1) In zones 334 and 344, general visual inspection 

(2) In zones 334 and 344, detailed visual inspection of lower stop angles of inboard hinge 

According to inspection results: 

(3) In zones 334 and/or 344, removal of the concerned elevator(s) 

(4) On the bench, on the LH elevator, replacement of the damaged angle(s) 

(5) On the bench, on the RH elevator, replacement of the damaged angle(s) 

(6) In zones 334 and/or 344, re-installation of the removed elevator(s) 

D. APPROVAL

The technical content of this document is approved in accordance with 

CE 1702/2003 regulation and is rendered mandatory by an EASA Airworthiness Directive. 

E. MANPOWER

(1) Valid for aircraft on which there is no angle replaced 

Manhours 

Mechanic 4 

Electrician None 

Total manhours 4 

Elapsed time (hours) 2 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

Page PI-4 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

(2) Valid for aircraft on which there are four angles replaced 

Manhours 

Mechanic 60 

Electrician None 

Total manhours 60 

Elapsed time (hours) 30 

The above estimates are only provided for general guidance in operator's modification 

planning. 

NOTE: This Service Bulletin assumes that the aircraft has been placed in the appropriate 

maintenance configuration. The manhours/elapsed time estimates do not include 

preparation for the inspection, non-productive elapsed time or administrative 

functions. 

F. WEIGHT AND BALANCE

None. 

G. REFERENCES

The following publications have to be used during accomplishment of this Service Bulletin: 

AMM : 06-41-30 

 

AMM (JIC) : 24-40-00 EAD 10000

55-20-00 RAI 10000

 

NDTM : 51-90-00 

 

SRM : 51-22-03 

51-35-00 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

Page PI-5 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

H. AFFECTED PUBLICATIONS

The following publications will be updated after receipt of the Accomplishment Report by 

ATR. 

None. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page MI-1 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

2. MATERIAL INFORMATION

A. MATERIAL - COST AND AVAILABILITY

(1) Material 

Parts cost and availability, or any further commercial information about Service 

Bulletin, may be consulted through ATRactive or operator should contact ATR at the 

following addresses: 

www.atractive.com 

ATR CUSTOMER SERVICES 

SPARES SUPPORT 

1 ALLEE PIERRE NADOT 

31712 BLAGNAC CEDEX 

FRANCE 

phone : +33 (0)5 62 21 60 33 

fax : +33 (0)5 62 21 62 80 

e-mail : spares.quotations@atr.fr 

Or operator should contact the ATR center he is related to, according to his 

operational area, at the following addresses: 

ATR NORTH AMERICA 

45195 BUSINESS COURT, SUITE 450 

DULLES, VIRGINIA 20166 

USA 

phone : +1 571 203 6920 

fax : +1 571 203 6903 

e-mail : commercialservices@atrnorthamerica.com 

ATR EASTERN SUPPORT Pte Ltd. 

77 LOYANG WAY 

SINGAPORE 508765 

phone : +65 6542 0122 

fax : +65 6542 1047 

Operator should place his purchase order specifying parts reference through 

ATRactive or to the ATR center he is related to according to his operational area. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page MI-2 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

B. LIST OF COMPONENTS

Item Part Number Qty Description 

 

 Material 

 

1 S5527200021401 2 Angle 

2 S5527200021201 2 Angle 

5 S5527200021000 2 Shim 

10 NTA12250-5DD12 4 Rivet 

11 NTA12250-4DD12 4 Rivet 

15 MS21074L3 4 Nut 

16 NTA12350-3A3 8 Rivet 

NOTE: These quantities are maximum and are presented for the replacement of the four 

angles. 

C. LIST OF MATERIALS - OPERATOR SUPPLIED

Item Description Reference 

SRM 51-35-00 

Qty per 

aircraft 

 

 Polysulfide sealant 09-001F As required 

 Alodine 13-002 As required 

 Primer 16-001C As required 

 

NOTE: The above materials can be procured by means of a spares purchase order. 

D. SPECIAL TOOLS

Accomplishment of this Service Bulletin requires use of the following special tools: 

None. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-1 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

3. ACCOMPLISHMENT INSTRUCTIONS

A. GENERAL

The following instructions assume that work will be accomplished when the aircraft is in 

the appropriate maintenance configuration. 

B. JOB SET-UP

(1) De-energize the aircraft electrical network and connect the aircraft to ground as per 

AMM (JIC) 24-40-00 EAD 10000. 

(2) Display warning notice in flight compartment prohibiting operation of elevator control. 

(3) In zones 334 and 344, remove access panels 333CB and 343CB (Refer to 

AMM 06-41-30). 

(4) Maintain elevators in full nose up position (trailing edge upward). 

C. INSPECTION

(1) In zones 334 and 344, general visual inspection 

Perform a general visual inspection on inboard hinge fitting area at level of LH and RH 

elevator front spars as per NDTM 51-90-00. 

In case of findings, contact ATR for approved solution to: 

ATR ENGINEERING 

STRUCTURE DEPARTMENT 

phone : +33 (0)5 62 21 65 61 

fax : +33 (0)5 62 21 62 92 

e-mail : techdesk@atr.fr 

(2) In zones 334 and 344, detailed visual inspection of lower stop angles of inboard hinge 

fittings 

As per Figure 1 

Position a mirror behind lower stops installation and perform a detail visual inspection 

of lower stop angles Item 1 and Item 2 as per NDTM 51-90-00. 

Pay a particular attention to check absence of cracks in radius. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-2 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

If there is no damage, perform Para 3.F. 

In case of damage perform Para. 3.D., 3.E. and 3.F. 

Para. 3.D.(2) has to be performed in case of damage detected on LH elevator 

angle(s). 

Para. 3.D.(3) has to be performed in case of damage detected on RH elevator 

angle(s). 

D. MODIFICATION

(1) In zones 334 and/or 344, removal of the concerned elevator(s) 

Remove the concerned elevator(s) as per AMM (JIC) 55-20-00 RAI 10000. 

(2) On the bench, on the LH elevator, replacement of the damaged angle(s) 

(a) Removal of the stop 

Remove all the parts listed in the following table. 

REMOVAL 

Item Description Part Number Qty 

Discarded 

Qty 

Re-used Figure

 

3 Screw NAS1802-3-10 - 2 1 

4 Stop S5527200020000 - 1 1 

5 Shim S5527200021000 1 - 1 

 

(b) Removal of the damaged angle(s) 

As per Figure 1, sheets 1 and 2 

Remove the damaged angle Item 1, P/N S5527200021400 and/or angle Item 2, 

P/N S5527200021200 with rivet Item 10, P/N NTA12250-5DD (Qty 1 per angle) 

and rivet Item 11, P/N NTA12250-4DD (Qty 1 per angle). 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-3 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

(c) Perform a detail visual inspection of adjacent areas. 

In case of findings, contact ATR for approved solution to: 

ATR ENGINEERING 

STRUCTURE DEPARTMENT 

phone : +33 (0)5 62 21 65 61 

fax : +33 (0)5 62 21 62 92 

e-mail : techdesk@atr.fr 

(d) Installation of the new angle(s) 

As per Figure 1, sheets 1 and 2 

1 Put in position the new shim Item 5, P/N S5527200021000 on the stop 

Item 4, P/N S5527200020000 retained at removal Para. 3.D.(2)(a). 

Be careful to position the laminated portion of the shim Item 5 in contact with 

the stop Item 4. 

2 Install the stop/shim assembly on the hinge fitting Item 20. 

Take care to ensure flat contact between hinge fitting Item 20 and shim 

Item 5. 

Respect a gap of 0.3 mm ± 0.2 mm (0.0118 in ± 0.0078 in) between the 

stop/shim assembly and the elevator front spar horizontal flange. 

3 Put and maintain in position the stop/shim assembly on the hinge fitting 

Item 20. 

4 Put and maintain in position the new angle(s) Item 1, P/N S5527200021401 

and/or Item 2, P/N S5527200021201 in contact with the hinge fitting Item 20 

and the shim Item 5. 

5 Drill hole(s) A between 4.826 mm and 4.928 mm (0.190 in and 0.194 in). 

Remove stop/shim assembly and the angle(s). 

Protect hole(s) A with Alodine Material No. 13-002 and Primer Material 

No. 16-001C (Refer to SRM 51-35-00). 

6 Install new nut Item 15, P/N MS21074L3 (Qty 1 per angle), attach with rivet 

Item 16, P/N NTA12350-3A3 (Qty 2 per nut). 

7 As per Figure 1, sheet 2, section H-H (schematic for flat contact checking) put 

in position the angle(s) on the hinge fitting flanges Item 20. Using the stop 

Item 4, check the correct alignment between angles Items 1 and 2 and the 

hinge fitting flanges Item 20. 

The flange of angles does not protrude from hinge flanges. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-4 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

8 Install new angle Item 1, P/N S5527200021401 and/or new angle Item 2, 

P/N S5527200021201, attach with rivet Item 10, P/N NTA12250-5DD12 

(Qty 1 per angle) and rivet Item 11, P/N NTA12250-4DD12 (Qty 1 per angle). 

9 Install new shim Item 5, P/N S5527200021000 and stop Item 4, 

P/N S5527200020000 (retained at removal Para. 3.D.(2)(a)), attach with 

2 screws Item 3, P/N NAS1802-3-10 (retained at removal Para. 3.D.(2)(a)). 

Be careful to position the laminated portion of the shim Item 5 in contact with 

the stop Item 4. 

Tighten Item 3 at 3 N.m to 3.5 N.m (26.552 in.lbf to 30.978 in.lbf). 

(3) On the bench, on the RH elevator, replacement of the damaged angle(s) 

(a) Removal of the stop 

Remove all the parts listed in the following table. 

REMOVAL 

Item Description Part Number Qty 

Discarded 

Qty 

Re-used Figure

 

3 Screw NAS1802-3-10 - 2 1 

4 Stop S5527200020000 - 1 1 

5 Shim S5527200021000 1 - 1 

 

(b) Removal of the damaged angle(s) 

As per Figure 1, sheets 1 and 2 

1 If the replacement of angle Item 2 is necessary, remove and retain the nut 

Item 6, the screw Item 7 and the washers Items 8 and 9 in order to 

disconnect the two bonding leads. 

2 Remove the damaged angle Item 1, P/N S5527200021400 and/or angle 

Item 2, P/N S5527200021200 with rivet Item 10, P/N NTA12250-5DD 

(Qty 1 per angle) and rivet Item 11, P/N NTA12250-4DD (Qty 1 per angle). 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-5 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

(c) Perform a detail visual inspection of adjacent areas. 

In case of findings, contact ATR for approved solution to: 

ATR ENGINEERING 

STRUCTURE DEPARTMENT 

phone : +33 (0)5 62 21 65 61 

fax : +33 (0)5 62 21 62 92 

e-mail : techdesk@atr.fr 

(d) Installation of the new angle(s) 

As per Figure 1, sheets 1 and 2 

1 Put in position the new shim Item 5, P/N S5527200021000 on the stop 

Item 4, P/N S5527200020000 retained at removal Para. 3.D.(3)(a). 

Be careful to position the laminated portion of the shim Item 5 in contact with 

the stop Item 4. 

2 Install the stop/shim assembly on the hinge fitting Item 20. 

Take care to ensure flat contact between hinge fitting Item 20 and shim 

Item 5. 

Respect a gap of 0.3 mm ± 0.2 mm (0.0118 in ± 0.0078 in) between the 

stop/shim assembly and the elevator front spar horizontal flange. 

3 Put and maintain in position the stop/shim assembly on the hinge fitting 

Item 20. 

4 Put and maintain in position the new angle(s) Item 1, P/N S5527200021401 

and/or Item 2, P/N S5527200021201 in contact with the hinge fitting Item 20 

and the shim Item 5. 

5 Drill hole(s) A and B between 4.826 mm and 4.928 mm (0.190 in and 

0.194 in). 

Remove stop/shim assembly and the angle(s). 

Protect hole(s) A with Alodine Material No. 13-002 and Primer Material 

No. 16-001C (Refer to SRM 51-35-00). 

6 If angle Item 2 must be replaced, perform an electrical bonding at level 

of hole B on each side of the angle (see detail G, Figure 1) as per 

SRM 51-22-03. 

7 Install new nut Item 15, P/N MS21074L3 (Qty 1 per angle), attach with rivet 

Item 16, P/N NTA12350-3A3 (Qty 2 per nut). 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-6 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

8 As per Figure 1, sheet 2, section H-H (schematic for flat contact checking) put 

in position the angle(s) on the hinge fitting flanges Item 20. Using the stop 

Item 4, check the correct alignment between angles Items 1 and 2 and the 

hinge fitting flanges Item 20. 

The flange of angles does not protrude from hinge flanges. 

9 Install new angle Item 1, P/N S5527200021401 and/or new angle Item 2, 

P/N S5527200021201, attach with rivet Item 10, P/N NTA12250-5DD12 

(Qty 1 per angle) and rivet Item 11, P/N NTA12250-4DD12 (Qty 1 per angle). 

10 Install new shim Item 5, P/N S5527200021000 and stop Item 4, 

P/N S5527200020000 (retained at removal Para. 3.D.(3)(a)), attach with 

2 screws Item 3, P/N NAS1802-3-10 (retained at removal Para. 3.D.(3)(a)). 

Be careful to position the laminated portion of the shim Item 5 in contact with 

the stop Item 4. 

Tighten Item 3 at 3 N.m to 3.5 N.m (26.552 in.lbf to 30.978 in.lbf). 

11 If the angle Item 2 has been removed at Para. 3.D.(3)(b) and replaced, 

re-install, as per Figure 1 Detail G, the two bonding leads and attach them 

with the nut Item 6, the screw Item 7 and the washers Items 8 and 9 retained 

at Para. 3.D.(3)(b). 

Tighten the nut Item 6 at 2 N.m ± 0.2 N.m (17.701 in.lbf ± 1.770 in.lbf). 

Protect bonding lead terminals and associated fasteners with polysulfide 

sealant Material No. 09-001F (Refer to SRM 51-35-00). 

(4) In zones 334 and/or 344, re-installation of the removed elevator(s) 

Re-install the removed elevator(s) as per AMM (JIC) 55-20-00 RAI 10000. 

E. TESTS

Verify that tests required by maintenance documents (AMM (JIC) 55-20-00 RAI 10000) 

mentioned on previous paragraph "MODIFICATION" have been performed. 

F. CLOSE-UP

(1) In zones 334 and 344, install access panels 333CB and 343CB 

(Refer to AMM 06-41-30). 

(2) Remove warning notice in flight compartment prohibiting operation of elevator control. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page AI-7 ©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

(3) Re-energize the aircraft electrical network and disconnect the aircraft from ground as 

per AMM (JIC) 24-40-00 EAD 10000. 

(4) Fill the enclosed Accomplishment Report and send it to the address mentioned on the 

Accomplishment Report. 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page IL-1 

©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

ILLUSTRATIONS 

Inspection and removal/installation of angles 

Figure 1, sheet 1 of 2 
SERVICE BULLETIN ATR42 

Original issue - May 11/10 Service Bulletin No. ATR42-55-0014 

 Page IL-2 

©Copyright 2010 Avions de Transport Régional - ATR - All rights reserved. 

Printed in France 

Inspection and removal/installation of angles 

Figure 1, sheet 2