ENGINEEI2ING NUMIII?R 

SNOW ENGINEERING CO. 

WICHITA FALLS,TEXAS REPORT 

SERVICE LETTER #245 

nrcns 

SUBJECT: 

Split Sleeve Co1d Expansion of Lower Spar Cap Holes - Rework of ln-service 

Aircraft in the 8-hole Configuration 

MODELS: 

AT-802, AT-802A S/N 802-0092 through 802-0178 

REFERENCE: 

(1) - Fatigue Technology Inc. Process Specification 8101D 

(2) - Snow Engineering Co. Drawing 20995, sheet 1 

C.F.NF.RAT, • 

This Service Letter provides a set of detailed instructions for cold 

working the 2 outboard-most wing center splice block holes in the lower 

spar cap. This document addresses airplanes in the 8 hole block 

configuration. 

For clarification, the splice block bolt holes are numbered from inboard to 

outboard. The inboard-most hole is defined as the "#1 Hole" and the 

outboard-most hole is defined as the "#8 Ho1e". See Figure 1 below. The 

terms "#8 Hole" and "#7 Hole" will be used throughout this document to 

identify holes being cold worked. 

~n #2 ~ ® ® n~ 

Figure 1- 8 Hole Block Numbering Scheme 

CAUTION: 

A MIS-DRILLED OR MIS-REAMED HOLE WILL RUIN THE SPAR CAP. THERE IS NO 

FIX FOR AN OVERSIZED OR EGG-SHAPED HOLE. OVERSIZED OR EGG-SHAPED 

HOLES WILL REQUIRE SPAR CAP REPLACEMENT. REPLACING A DAMAGED SPAR 

CAP CAN LEAD TO SIGNIFICANT COST AND SIGNIFICANT AIRCRAFT DOWNTIME. 

EXERCISE EXTREME CAUTION AND GOOD AVIATION MAINTENANCE PRACTICES 

AND TECHNIQUE WHEN PERFORMING THE STEPS IN THIS SERVICE LETTER. 
ENGINEEItING """"""` SNOW ENGINEERING CO. 

WICHITn F,u.LS,'rsxns REPORT 

(1RT1F.R X ma ~ >iti. 

SERVICE LETTER #245 

nnre 

EQUIPMENT: 

The tools required to accomplish this rework are separated into 3 different 

tool kits and are color coded for ease of identification. The "Ye11ow" 

Tool Kit A is used when cold working the "4k8 Holes". The "Blue" Too1 Kit B 

is used when cold working the "#7 Holes". The "Red" Tool Kit C contains 

all other general tools used for this process. The instructions in this 

document specify that each hole size be worked separately. This is not 

only to eliminate opportunities for tool selection errors, but also to hold 

the spar cap stackup in place during the cold working process. While 

working from the "Yellow" tool kit, the "B1ue" tool kit should be closed, 

latched, and out of reach. While working from the "Blue" tool kit, the 

"Yellow" tool kit should be closed, latched, and out of reach. 

P/N DESCRIPTION 

CASR-62-1 Starting Reamer (Ref .379 Dia.) 

CAG-62 Combination Gage 

CAMG-62 Mandrel Gage 

CAS-62-36F Flared Sleeve (2 ea.) 

CAM-62-2-60-V2 Mandrel 

MEN-26B-1223F Nosecap Assembly 

CAR-62-1-.4062 IGage Finish Reamer 

raple 1-'1'001 xat A^Ye11Ow TOO1 Kit° - 13/32 Sinished Holes (STDN = 62) 

P/N DESCRIPTION 

CASD-80-1-C Starting Dri11 (Ref .453 Dia) 

CASR-80-1 Starting Reamer (Ref .470 Dia.) 

CAG-80 Combination Gage 

CAMG-80 Mandrel Gage 

CAS-80-40F Flared Sleeve (2 ea.) 

CAM-80-2-60-V2 Mandrel 

MEN-26B-1601F Nosecap Assembly 

CAR-80-1-.5000 Gage Finish Reamer 

raple L - '1'001 nit 1s "i6171e '1'ool Kit" - 112 r- lnisnea Holes (STDN = 80) 

P/N DESCRIPTION 

MB-30 Medium Brute Pu11er Unit 

FT-20 Power Pak 

PS200-1 120 microinch surface finish comparator plate 

SK398-1 Cold Work Tooling Fixture (See SK398-1 for 

complete list of parts) 

'i•anle 6-'POOl xat c'~ aea Toot xit- - General Tools 
SNOW ENGINEERING CO. 

I ENGINEERING I "°"""` " 

WICHITA FALLS, TEXAS REPORT n 

SERVICE LETTER #245 

unrr> 

4/25/05 

PERSONNEL QUALIFICATION: 

In order to perform the steps in this Service Letter, personnel must: 

a.) possess the tooling specified in the "Equipment" section of this 

document. 

b.) be trained and certified for eddy current inspection. 

c.) attend an Air Tractor sponsored training course and receive a 

certificate of completion for the Split Sleeve Cold Expansion 

process. This requirement may also be fulfilled by attending a 

Fatigue Technology Inc. training session and receiving a Certificate 

of Training after the completion of that training. 

PROCEDURE: 

SECTION A- CLEAN AND GAIN ACCESS TO REPAIR AREA 

B. 1. Before accomplishing this Service Letter, thoroughly clean the 

airplane, especially the hopper, gatebox, and wing splice area. 

B. 2. Gain access to the repair area as follows: 

B. 2.1. Remove hopper dump push rod mechanism 

B. 2.2. Remove spray pump to spray valve tube 

B. 2.3. Remove bottom load fill tube 

B. 2.4. Remove spray pump supply tube 

B. 2.5. Remove gatebox fairing 

B. 2.6. Remove gatebox 

B. 2.7. Remove fiberglass enclosure skin 

SECTION 8- REMOVE HARDWARE, INSPECT #7 AND #8 HOLES 

B. 1. Shore aircraft wings as follows: 

B. 1.1. Place wing jacks at wing tie-down ring locations. 

B. 1.2. Simultaneously raise both jacks until jack pads "just 

contact" the tie-down ring on both left and right wings. 

B. 1.3. Simultaneously raise both jacks an additional 11/16 + 1/16 

to unload the bolts in the lower cap splice connection and 

facilitate bolt removal. 

B. 2. Identify the spar lower cap "#7 and #8 hole" bolt locations. See 

Figure 1. 

B. 3. Remove nuts from the two 3/8 bolts, both left and right side, in the 

lower wing spar splice using good aviation maintenance practice. 

Use 1/4" aluminum pin punch to CAREFULLY tap bolts up and out of 

lower spar cap and splice blocks. 

NOTE: USE EXTREME CAUTION NOT TO SCRATCH INSIDE OF HOLES WITH PUNCH. 

B. 4. Remove nuts from the two 7/16 bolts, both left and right side, in 

the lower wing spar splice using good aviation maintenance practice. 
SNOW ENGINEERING CO. ENGINEERING """"""` 

WICHITA PA1.I.S, TEXAS REPORT 

C1R11RR x monit. 

SERVICE LETTER #245 

DKIII 

Use 1/4" aluminum pin punch to CAREFULLY tap bolts up and out of 

lower spar cap and splice blocks. 

NOTE: USE EXTREME CAUTION NOT TO SCRATCH INSIDE OF HOLES WITli PUNCH. 

B. 5. Clean #7 and #8 holes using solvent and a soft bristle brush or rag. 

Use compressed air to remove all solvent residue from the holes. 

B. 6. Eddy Current inspect 47 and #8 Holes" per Air Tractor PS 197. 

IA~iIZoIC7H7~.1`Y W 

IF BOTH #7 HOLES AND BOTH #8 HOLES PASS THE EDDY CURRENT INSPEC7'ION 

IN PS 197, PROCEED WITH THE STEPS IN THIS SERVICE LETTER. IF ANY HOLES 

FAIL THE EDDY CURRENT INSPECTION IN PS 197, DISCONTINUE THIS SERVICE 

LETTER. 

SECTION C- COLD WORK #7 AND #8 HOLES 

C. 1. Install and locate SK398-1 attach block Tooling Fixture (See SK398): 

C. I.I. Remove the two #3 5/8" dia. bolts from the center splice. 

Install the tooling fixture with two 5/8" dia. studs, nuts, 

and washers as shown on SK398. Tighten the stud nuts. 

C. 1.2. Install drill press onto the drill press mounting plate. 

Do not tighten 2 mounting bolts. 

C. 1.3. Lock Tapered Alignment Pin into drill chuck. 

C. 1.4. Position drill press so alignment pin slips into ho1e. 

C. 1.5. With Tapered Pin still in hole, tighten 2 mounting bolts. 

C. 1.6. Withdraw drill chuck from hole and remove alignment pin. 

C. 1.7. Dri1l fixture is now aligned with hole. 

COLD WORK "#8 HOLE" TO 13/32 (STANDARD TOOL DIAMETER NUMBER, STDN = 62) 

Note: Accomplish the following Cold Work steps concurrently for both 

the left hand and right hand '48 Holes". 

C. 2. Acquire "Yellow" Tool Kit A and inventory for proper tools using 

Table 1. 

C. 3. Ream the "#8 Hole" using the CASR-62-1 starting reamer. Sulfur based 

cutting oil should be used for starting hole ream and all subsequent 

ream steps. After reaming, move SK398-1 Tooling Fixture out of the 

way and clean the hole with solvent and dry with compressed air. 

See Figure 2. 
SNOW ENGINEERING CO. 

WICHITA FALLS, TEXAS 

SERVICE LETTER #245 

ENGINEERING """"""` 

REPORT _ 

ORDER X ntOD1' 

1)Y CHK9) 

Leland Snow 

mme 

oO 0 

Starting Reamer 

Figure 2 

C. 4. The starting hole diameter must be .379 -.382. Check the starting 

hole using the CAG-62 Go-No Go Combination Gage, or a ba11 gage and 

micrometer. When using the Go-No Go Combination Gage, a gage that 

can only be inserted to the first machined "step" identifies a 

properly reamed hole. The starting hole should be checked for 

ovality by inserting the gage a second time, rotated 90 ° . See Figure 

3. 

O 

O 

~ Accept 

~ 

Figure 3 

Reject 

C. 5. Select the CAM-62-2-60-V2 mandrel and inspect using the CAMG-62 GoNo Go gage or a micrometer. The mandrel major diameter shall be 

.3692 -.3702. The mandrel shall be checked at the beginning of 

each aircraft job because the mandrel diameter is critical for 

proper cold expansion of the hole. An excessively worn mandrel will 

pass through the CAMG-62 Go-No Go gage and shall be replaced. If 

the mandrel fails the diameter check, contact Air Tractor Customer 

Service Department for a replacement mandrel. See Figure 4. 

~

Mandrel Check Fixture 

O 

Accept Rejectand Discard Mandrel 

FiQure 4 

C. 6. Clean the hole using solvent and a soft bristle brush or rag. Use 

compressed air to remove all solvent residue from the holes. 
SNOW ENGINEERING CO. 

ENGINEERING """"""` 

WICHITA FALLS, TEXAS REPORT 

(1RT1RR % mour.i. 

SERVICE LETTER #245 

nnrc 

C. 7. Cold expand the hole. See Figure 5: 

C. 7.1. Select the CAS-62-32F split sleeve and slide it over the 

mandrel. orient sleeve so that the split is pointing along 

the spar cap centerline facing inboard and the flared end 

is toward the Puller nosecap. 

C. 7.2. Insert the mandrel and sleeve into the starting hole. 

Ensure sleeve orientation is correct per step 13.1 above. 

The sleeve should protrude from the topside of the hole 

1/32",or more. 

C. 7.3. Place nosecap firmly against and perpendicular to the lower 

surface of the splice block. 

C. 7.4. Activate Puller. Continue holding the trigger until 

mandrel is through the entire lower spar cap stackup. 

Release trigger when the mandrel is clear of the structure. 

C. 7.5. Remove sleeve from the cold worked hole and discard. 

Sleeves are used only once. 

0 

0 

SPLIT FACES 

INBOARD 

C. 8. Check the cold expanded hole diameter using the CAG-62 Go-No Go 

Combination gage. The gage will fit into a properly expanded hole. 

The cold worked hole should measure .3840 as a minimum before the 

finish ream process. If the Go-No Go Combination gage will not fit 
SNOW ENGINEERING CO. 

WICHITA FALLS,TEXAS 

SERVICE LETTER #245 

ENGINEERING N"A101" 

REPORT 

ORDER X nwula. 

IIV <:IIA'n 

Leland .CJnow yi'I""i' 

unT: 

into the hole, check for proper tool selection, check mandrel for 

proper diameter, then follow step 13 a second t- ime. NoL- e that a 

surface upset is created during the cold working process at each hole 

face. This surface upset is normal. See Figure 6. 

~~ ~ 

Go-No-Go Gage 

0 

a 

Combination Gage —\ 

NN 

Gage Finish Reamer 

Gage Finish Reamer~ 

NN 

NN 

or Hole has been 

cold expanded, 

NN 

KN 

or Hole has not been 

cold expanded. Li 

Fieure 6 

C. 9. Follow the Tooling Fixture alignment procedure previously described. 

C. 10. Finish ream the cold worked hole using the CAR-62-1-.4062 gage 

finish reamer. Finish reamed final hole must have a surface 

roughness of 120 microinches or smoother measured with surface 

finish comparator plates. See Figure 7. 

0 

0 

Finish Reamer 

Figure 7 

C. 11. Inspect finished hole. Finish reamed final hole must have a 

diameter of .4058 +-002 /-.000 and must have a surface roughness of 
I 

SNOW ENGINEERING CO. 

ENGINEERING ^ 

WICHITA FAi.7.s, TEXAS REPORT I 1 

SERVICE LETTER #245 

un n: 

120 microinches or smoother measured with surface finish comparator 

plates. Holes may be inspected using a ball gauge and micrometer, 

or air gauge with the proper calibrated hole standards. 

C. 12. Install new hardware in accordance with Drawing 20995, sheet 1. 

SECTION 3- REMOVE RARDWARE, INSPECT, COLD A)ORK 47 HOLE" TO 1/2 HOLE 

(STANDARD TOOL DIAMETER NOMIDER, STDN = 80) 

C. 13. Acquire "Blue" Tool Kit B and inventory for proper tools using Table 

2. 

C. 14. Identify the spar lower cap "#7 Hole" bolt locat- ions. See Figure 1. 

C. 15. Remove clamp bolts at #6 hole locations. 

C. 16. Clean holes using solvent and a soft bristle brush or rag. Use 

compressed air to remove all solvent residue from the holes. 

C. 17. Follow the Tooling Fixture alignment procedure previously described. 

C. 18. Drill the entire stackup of upper and lower blocks and lower cap at 

the "#7 Hole" location using CASD-80-1-C starting drill. Sulfur 

based cutting oil should be used for starting hole drill and all 

subsequent ream steps. 

C. 19. Ream the "#7 Hole" using the CASR-80-1 starting reamer. After 

reaming, move SK398-1 Tooling Fixture out of the way and clean the 

hole with solvent and dry with compressed air. See Figure 8. 

Starting Drill 

Starting Reamer Figure 8 

C. 20. The starting hole diameter must be .470 -.473. Check the starting 

hole using the CAG-80 Go-No Go Combination Gage, or a ball gage and 

micrometer. When using the Go-No Go Combination Gage, a gage that 

can only be inserted to the first machined "step" identifies a 

properly reamed hole. The starting hole should be checked for 

ovality by inserting the gage a second time, rotated 90 0 . See Figure 

9. 
SNOW ENGINEERING CO. 

WICHITA FALLS,TEXAS 

ENGINEERING I """'" 

REPORT n 

SERVICE LETTER #245 

DA'115 

0 

0 

~ Accept _ Reject - 

~ 

Figure 9 

C. 21. Select the CAM-80-2-60-V2 mandrel and inspect using the CAMG-80 GoNo Go gage or a micrometer. The mandrel major diameter shall be 

..4643-4653. The mandrel shall be checked at the beginning of each 

 aircraft job because the mandrel diameter is critical for proper 

cold expansion of the hole. An excessively worn mandrel will pass 

through the CAMG-80 Go-No Go gage and shall be replaced. If the 

mandrel fails the diameter check, contact Air Tractor Customer 

Service Department for a replacement mandrel. See Figure 10. 

~

Mandrel Check Fixture 

a 

~ )0 

Accept Reject and Discard Mandrel 

Figure 10 

C. 22. Clean the hole using solvent and a soft bristle brush or rag. Use 

compressed air to remove all solvent residue from the holes. 

C. 23. Cold expand the hole. See Figure 11: 

C. 23.1. Select the CAS-80-36F split sleeve and slide it over the 

mandrel. Orient sleeve so that the split is pointing along 
SNOW ENGINEERING CO. ENGINEERING NIIMIII11l 

WtCHrrn P,va.s, TexnS REPORT

x 

# 2 4 5 

ORDER Moulal. 

rrrce nv cnnIo See BelOW 

SERVICE LETTER #245 Leland Snow sl"`In'. 

nn•n; 

rn<a: or 

4/25/05 1n 12 

the spar cap centerline facing inboard and the end is 

toward the Pu11er nosecap. 

C. 23.2. Znsert the mandrel and sleeve into the starting hole. 

Ensure sleeve orientation per step 29.1 above. The sleeve 

should protrude from the topside of the hole 1/32" or more. 

C. 23.3. Place nosecap firmly against and perpendicular to the lower 

surface of the splice block. 

C. 23.4. Activate Puller. Continue holding the trigger until 

mandrel is through the entire lower spar cap stackup. 

Release trigger when mandrel is clear of the structure. 

C. 23.5. Remove sleeve from the cold worked hole and discard. 

Sleeves are used only once. 

SPLIT FACES INBOARD 

Figure 11 

C. 24. Check the cold expanded hole diameter using the CAG-80 Go-No Go 

Combination gage. The gage will fit into a properly expanded hole. 

The cold worked hole should measure .4780 as a minimum before the 

finish ream process. If the Go-No Go Combination gage will not fit 

into the hole, check for proper tool selection, check mandrel for 

proper diameter, then follow step 30 a second time. Note that a 
SNOW ENGINEERING CO. ENGINEERING NUMnNR 

WICHITA FALLs, TEXAs REPORT # 2 4 5 

ORDER x M°n"'• 

TrrLE nv r•nn'n See Below 

SERVICE LETTER #245 Leland Snow "`"'"'' 

nnTc 

rncaa oV 

4/25/05 17 12 

surface upset is created during the cold working process at each 

hole face. This surface upset is normal. See Figure 12. 

Combination Gage ~ 

NN 

Gage Finish Reamer-~ 

fzzq 

NN 

NN 

or 

0 

Go-No-Go Gage 

~0 

~ Gage Finish Reamer 

Hole has been 

cold expanded. 

or Hole has not been 

cold expanded. 

Fieure 12 

C. 25. Follow the Tooling Fixture alignment procedure previously described. 

C. 26. Finish ream cold worked hole using CAR-80-1-.5000 gage finish 

reamer. Finish reamed final hole must have a surface roughness of 

120 microinches or smoother measured with surface finish comparator 

plates. See Figure 13. 

0 

0 

Finish Reamer 

Figure 13 

C. 27. Inspect finished hole. Finish reamed final hole must have a 

diameter of .4995 +.002 /-.000 and must have a surface roughness of 

120 microinches or smoother measured with surfacefinish comparator 
SNOW ENGINEERING CO. 

I ENGINEERING NIIMIIISIt 

WICHITA FALLS, TEXAS REPORT n 

SERVICE LETTER #245 

nn•re 

5 

plates. Holes may be inspected using a ball gauge and micrometer, 

or air gauge with the proper calibrated hole standards. 

C. 28. Install new hardware in accordance with Drawing 20995, sheet 1. 

SECTION 4- REASSEMSLE AIRPLANE AND RETIIRN TO SERVICE 

C. 29. Reinstall gatebox and all equipment removed in accordance with 

Airplane Owners Manual. 

C. 30. Make the following maintenance log entry in aircraft logbook: 

"This aircraft, Air Tractor (model number)-(s/n), has been reworked 

in accordance with Snow Engineering Co. Service Let- ter #245 and is 

approved for return to service, this date (date), signed 

(signature), (certificate and number).