This report covers flight evaluation of composite inboard ailerons on the L-1011 under Contract NAS 1-15069 for a period of five years. This is the fourth annual report of the maintenance evaluation program, and covers the period from May 1985 when the third yearly inspections were completed, through July 1986. Four shipsets of graphite/epoxy composite inboard ailerons were installed on L-1011 aircraft for this maintenance evaluation program. These include two Delta aircraft and two TWA aircraft. A fifth shipset of composite ailerons was installed in 1980 on Lockheed's flight test L-1011. One instance of minor damage was observed on one of the composite ailerons and was repaired. No other maintenance actions have occurred on any of the composite parts except for repainting of areas with paint loss. Flight hours on the airline components at the time of inspection ranged from 12,051]en1] to 14,046 hours, after approximately 4 years of service

Stone, R. H.

English

NASA Technical Reports Server

NASA Contractor Report 1781 70 
Flight Service Evaluation of 
Advanced Composite Ailerons 
on the L - I  01 I Transport 
Aircraft 
Fourth Annual Flight Service Report 
R.H. Stone 
LOCKHEED-CALIFORNIA COMPANY 
BURBANK, CALIFORNIA 
CONTRACT NAS 1-1 5069 
July 1986 
(NASA-CR- 178179) P L I G H T  SERVICE E V A L U A T I O N  Nd 7- 1 6 S & 3  
C F  A D V A H C b D  C C A E C S I T E  A I L E i C b S  C h  THE L-1011 
X B A N S P O R T  A I B C R A F l  A n n u d l  E l i q h t  Service 
1 4  P CSCZ 11D G3/24 4 3 3 7 9  
B e g o r t  ( L o c k h e e d - C a l i f o r n i a  Co., Eurbank.) Uuclas 
National Aeronautics and 
Space Administration 
Langley Research Center 
Hampton, Virginia 23665-5225 
https://ntrs.nasa.gov/search.jsp?R=19870007450 2020-03-20T12:49:40+00:00Z
FOREWORD 
This report was prepared by Lockheed-California Company, Burbank, 
California under Contract NAS 1-15069. It is the fourth annual report 
covering flight service evaluation of composite inboard ailerons on the L-1011 
from May 1985 when the third yearly inspections were completed, through July 
1986. The program is sponsored by the National Aeronautics and Space 
Administration (NASA), Langley Research Center. 
Project Engineer for NASA. 
Mr. Marvin B. Dow is the 
C. F. Griffin is the Lockheed Engineering Program Manager and is being 
assisted in the flight service evaluation by R. H. Stone. 
Use of commercial products or names of manufacturers in this report does 
not constitute official endorsement of such products or manufacturers, either 
expressed or implied, by the National Aeronautics and Space Administration. 
i 
TABLE OF CONTENTS 
Sect ion 
FOREWORD 
SUMMARY 
INTRODUCTION 
F L I G H T  S E R V I C E  EVALUATION PLAN 
AILERON F L I G H T  S E R V I C E  EXPERIENCE 
REFERENCES 
i i i  
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i 
V 
1-1 
2-1 
3-1 
R- 1 
SUMMARY 
Four shipsets of graphitelepoxy composite inboard ailerons were installed 
on L-1011 aircraft in March through May 1982 for a five-year maintenance 
evaluation program. These include two Delta aircraft and two TWA aircraft. A 
fifth shipset of composite ailerons was installed in 1980 on Lockheed's flight 
test L-1011. 
Results of the fourth annual inspection of these five shipsets of 
components are reported herein. 
exterior surfaces. 
These were visual inspections of the aileron 
One incident of minor damage was observed on one of the composite 
ailerons and was repaired. 
the parts except for repainting of areas with paint loss. 
airline components at the time of inspection ranged from 12,051 to 14,046 
hours, after approximately four years of service. 
No other maintenance action has occurred on any of 
Flight hours on the 
V 
SECTION 1 
INTRODUCTION 
R 
In 1977 the Lockheed-California Company initiated a program to demon- 
strate the weight and cost-saving potential of secondary aircraft structures 
constructed of advanced composite materials. The component selected for this 
demonstration was the inboard aileron of the L-1011 transport aircraft. The 
program is sponsored by the National Aeronautics and Space Administration as 
part of the Aircraft Energy Efficiency (ACEE) Composite Structures Program. 
The program scope included the evaluation of alternate designs and 
materials for the aileron; detail design and analysis; fabrication and test of 
subcomponents for design verification; fabrication and testing of two ground 
test ailerons; fabrication of five shipsets of ailerons for installation on 
L-1011 aircraft; flight testing of one shipset on Lockheed's flight test 
aircraft; and the 5 year flight service evaluation discussed herein. The 
overall program is summarized in the executive summary report (Ref. 1) .  
Lockheed's team member on this program was Avco Aerostructures Division of 
Avco Corporation. Avco was responsible for fabrication of the composite 
ailerons. 
The composite aileron design, shown in Figure 1, is a multirib config- 
uration with single piece upper and lower covers mechanically fastened to the 
substructure. Three basic materials were utilized in the aileron design: 
Narmco 5208/T300 graphite/epoxy unidirectional epoxy tape; Narmco 5208/T300 
graphitelepoxy bidirectional fabric: and Hysol ADX 819 syntactic epoxy core. 
The aileron covers, ribs, and front spar were fabricated using standard 
vacuum bag autoclave molding procedures. The aileron covers are thin sandwich 
plates with graphitelepoxy tape facesheets and a syntactic epoxy core. 
r i b s  and spars are constant thickness channel sections, laid up and cured on 
male tools. The intermediate ribs are fabricated of bidirectional graphite1 
The 
1-1 
BACK4P FITTINGS 
SYNTACTIC CORE 
FRONT SPAR/ RIBS 
GRlEP TAPE GRlEP FABRIC 
Figure 1. - Advanced Composite Aileron Assembly 
epoxy fabric. The main ribs which react hinge and actuator loads are fabri- 
cated of graphite/epoxy fabric, with the caps reinforced with graphite/epoxy 
tape. The front spar is fabricated of graphitelepoxy tape laid up in approx- 
imately a quasi-isotropic orientation. 
The complete aileron assembly includes an aluminum leading edge shroud, 
aluminum bathtub €€ttings at the spar to main rib joints, fiberglass/epoxy 
fairings, aluminum hinge/actuator fittings, and a Kevlar 49/epoxy trailing 
edge. The composite aileron design is 26% lighter than the metal aileron and 
is predicted to be cost competitive since the composite aileron has 50% fewer 
parts and fasteners than the metal aileron. 
n 
The inboard aileron is located on the wing trailing edge between the 
outboard and inboard trailing edge flaps. It is supported from the wing at 
two hinge points and is actuated by three hydraulic actuators. 
shaped, one-cell box, thinning slightly from root t o  tip. At the front spar 
the aileron is 233.7 cm (92 in.) in length and approximately 25.4  cm (10 in.) 
It is a wedge- 
1-2 
deep. 
and spars are permanently fastened using titanium Triwing screws and stainless 
steel Hi-Lok collars. 
end fairings are attached with the same type screws but with nut plates at- 
tached to the structure with A286 Cherry Rivets. 
with sealant. The aileron i s  primed and painted with standard aircraft 
materials. 
The width of the aileron is 127 cm ( 5 0  in.). The upper surface, ribs, 
The removable lower surface, trailing edge wedge, and 
All fasteners are installed 
1-3 
SECTION 2 
FLIGHT SERVICE EVALUATION PLAN 
The final phase of the inboard aileron program is a five-year flight 
service evaluation. 
new L-1011 aircraft. 
Delta Air Lines, and the two others were delivered to Trans World Airlines. 
The Delta aircraft were the standard L-1011-1 model, while the TWA aircraft 
were longer range L-1011-100s. 
A left-hand and right-hand aileron were installed on four 
Two of these aircraft were subsequently delivered to 
The evaluation agreement between Lockheed and the two participating 
airlines consisted of the following elements: 
The evaluation period is five years. 
An exterior visual inspection will be performed by airline personnel 
and witnessed by Lockheed personnel at annual scheduled "C"-check 
inspections closest to the anniversary of installation. 
An interior inspection, requiring removal of the lower cover, will be 
conducted at the end of the five-year evaluation by airline 
personnel, witnessed by Lockheed personnel. 
The airlines will provide a written report to Lockheed on the results 
of each inspection. This report will include inspection results, a 
description of any maintenance o r  repair actions, flight hours, 
number of landings, and utilization rate for the year. 
In the event visible damage is observed, the airlines will determine 
the extent of damage by ultrasonic inspection using standards pro- 
vided by Lockheed. After notification of Lockheed, the airline will 
repair the damage in accordance with the L-1011 Structural Repair 
Manual, which was revised to incorporate specific repair procedures 
for the composite ailerons. 
A fifth shipset of ailerons were installed on the Lockheed flight test 
airplane as part of FAA certification. These flight tests are described in 
the Task IV Final Report (Ref. 2 ) .  A visual inspection of the exterior and 
interior aileron surfaces was conducted by Lockheed personnel after the first 
2-1 
and second years of flight service, but the third-year inspection was can- 
celled since there had been only 10 1 / 2  hours flight-time during the previous 
year. This aircraft has recently undergone additional flights prior to deli- 
very in late July 1986 to Aviation Sales Co. of Miami, Florida. 
Sales will use the aircraft for spares, and will thus acquire the composite 
ailerons. A final visual inspection was therefore performed by Lockheed 
personnel prior t o  delivery. 
Sales to monitor future disposition of these components. 
Aviation 
Lockheed will maintain contact with Av€ation 
c 
Y 
2-2 
SECTION 3 
AILERON FLIGHT SERVICE EXPERIENCE 
The first, second and third annual flight service inspections of the five 
ailerons shipsets were conducted in March through July of 1983 ,  April through 
July of 1984 and April and May of 1985. the results of these inspections are 
given in the First, Second and Third Annual Flight Service Reports (Refs. 3 ,  4 
and 5 ) .  
those inspections. 
No damage or defects were observed in any of the ten ailerons in 
The inspection results for the fourth year of flight service are summar- 
ized in Table 1, along with utilization rate and aircraft flight-hours and 
landings as of the inspection date for the composite ailerons. A total of 
106,066 component flight-hours were accumulated through July 1986 on the ten 
installed ailerons. 
hours in four years. 
The high time ailerons have accumulated 14,046 flight 
The fourth annual visual inspections of the composite ailerons revealed 
only one minor damage incident on the ten components. This was an area of 
delaminated and loose surface fibers on either side of one fastener along the 
forward edge of the left-hand aileron lower surface on the Lockheed flight 
test airplane. This fastener was near the area where the outboard hinge 
actuators attach to the front spar and main rib. The delaminations were 
approximately 3 .8  cm. ( 1  1/2 inches) long by 1 . 3  cm. (1 /2  inches) wide, and 
were evenly spaced on either side of the fastener equidistant between it and 
the adjacent fasteners. This damage was of minor nature and was repaired by 
application of an epoxy resin to bond the fibers back into place followed by 
repainting . 
Minor paint loss was observed on all the ailerons, and touch-up paint was 
applied in some cases. Extensive paint loss (15-20%) was noted on the lower 
surface of one TWA component and on the upper surface of one of the Lockheed 
components. In addition, Delta reported repainting of all surfaces of one 
3-1 
aileron shipset in November 1985, after poor paint surface condition was 
noted. Paint chipping around fasteners was noted on most surfaces to varying 
degrees. There was also evidence of Skydrol exposure in most cases, parti- 
cularly along the main rib attachment locations directly aft of the actuators. 
Paint loss of this type is a fairly common occurrence on metal or 
fiberglass components. The significance for the graphite/epoxy ailerons is: 
1) paint loss indicates that the ailerons are being exposed to hydraulic 
fluid, and the lack of damage verifies the resistance of graphite/epoxy to 
aircraft fluids; 2)  the upper surface is exposed to ultraviolet, and epoxy 
resins are known to be affected by ultraviolet with significant weight losses 
after extended exposure. Lockheed and airline maintenance personnel were 
advised of the need for repainting of exposed graphite/epoxy, particularly on 
the upper surface. 
There was one instance of minor damage to components which are part of 
the inboard aileron assembly, but which are not made of graphite composite 
material. A small damage area was noted on a fiberglass end fairing on one of 
the Delta components. This was repaired by scarfing 3.8 cm. ( 1  1 /2  inches) 
around the damage, and applying two layers of 181 glass cloth impregnated with 
epoxy resin. The repair was cured at room temperature, and then finished to 
match the component. This incident does not reflect on the graphite aileron 
serviceability, but is indicative of the potential for in-service damage of 
this component and also illustrates a suitable repair scheme for repair of 
negligible damage on the graphite components. 
These results indicate that the graphite/epoxy components perform 
satisfactorily in the high utilization environment of commercial transports. 
The satisfactory structural performance of the ailerons and the absence of 
major damage or defects verifies the structural and durability data obtained 
in the composite aileron test program. 
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REFERENCES 
1. G r i f f i n ,  C.F. and Dunning, E.G., "Development of An Advanced Composite 
A i l e r o n  f o r  t h e  L-1011 Transpor t  A i r c r a f t , "  NASA c o n t r a c t o r  Repor t  3517, 
February  1982. 
2. G r i f f i n ,  C.F., "Advanced Composite A i l e r o n  f o r  L-1011 T r a n s p o r t  
A i r c r a f t  - Ground T e s t s  and F l i g h t  E v a l u a t i o n , "  NASA C o n t r a c t o r  Report  
165664, February 1981. 
3 .  S t o n e ,  R.H. ,  " F l i g h t  S e r v i c e  Eva lua t ion  of Advanced Composite A i l e r o n s  on 
t h e  L-1011 Transpor t  A i r c r a f t  - F i r s t  Annual F l i g h t  S e r v i c e  Repor t , "  NASA 
C o n t r a c t o r  Report  172246, September 1983. 
4. Stone ,  R .H. ,  " F l i g h t  S e r v i c e  Eva lua t ion  of Advanced Composite A i l e r o n s  on  
t h e  L-1011 Transpor t  A i r c r a f t  - Second Annual F l i g h t  S e r v i c e  Repor t , "  
NASA Con t rac to r  Report  172483, December 1984. 
5 .  S t o n e ,  R.H. ,  " F l i g h t  S e r v i c e  Evalua t ion  of Advanced Composite A i l e r o n s  on 
t h e  L-1011 Transpor t  A i r c r a f t  - T h i r d  Annual F l i g h t  S e r v i c e  Repor t , "  NASA 
C o n t r a c t o r  Report 177960, July 1985. 
R- 1 
1. Report No. 
NASA CR-178270 
7. Authorls) 
R.  H .  Stone 
2. Government Accession NO. 
9. Performing Organization Name and Address 
Lockheed-California Company 
P.O. Box 551 
Burbank, Ca l i fo rn ia  91520 
19. Security Clruif. (of this report) 20. Security Clruif. (of this paw) 21. NO. of Pages 
Unclass i f ied  Unc las s i f i ed  1 5  
- 
2. Sponsoring Agency Name and Address 
National  Aeronautics and Space Adminis t ra t ion 
Washington, DC 20546 
22. Price' 
A02 
3. Recipient's Catalog No. 
5. Report Date 
6. Performing Organization Code 
J u l y  1986 
~ 
8. Performing Organization Report No 
LR 31032 
10. Work Unit No. 
11. Contract or Grant No. 
NAS 1- 15069 
13. Type of Report and Period Covered 
Contrac tor  Report 
14. Sponsoring Agency Code 
534-06-23-0 1 
~~ 
5. Supplementary Notes 
Langley Technical Monitor: Marvin B. Dow 
Fourth Annual Fl ight  Serv ice  Report 
16 Abstract 
This  r e p o r t  covers f l i g h t  s e r v i c e  eva lua t ion  of composite inboard a i l e r o n s  on t h e  
L-1011 under Contract NAS 1-15069 f o r  a per iod of f i v e  years .  This  is the  f o u r t h  
annual r e p o r t  of the maintenance eva lua t ion  program, and covers  t h e  per iod  from May 
1985 when t h e  th i rd  year ly  in spec t ions  were completed, through J u l y  1986. 
Four s h i p s e t s  of graphi te /epoxy composite inboard a i l e r o n s  were i n s t a l l e d  on 
These inc lude  two Del ta  L-1011 a i r c r a f t  f o r  t h i s  maintenance eva lua t ion  program. 
a i r c r a f t  and two TWA a i r c r a f t .  
i n  1980 on Lockheed's f l i g h t  tes t  L-1011. 
A f i f t h  s h i p s e t  of composite a i l e r o n s  were i n s t a l l e d  
One in s t ance  of minor damage w a s  observed on one of the  composite a i l e r o n s  and 
w a s  r epa i r ed .  
p a r t s  except  f o r  repa in t ing  of a r e a s  wi th  p a i n t  l o s s .  
components a t  t h e  t i m e  of i n spec t ion  ranged from 12,051 t o  14,046 hours ,  a f t e r  
approximately 4 years of s e rv i ce .  
No o t h e r  maintenance a c t i o n s  have occurred on any of t h e  composite 
F l i g h t  hours  on the  a i r l i n e  
17. Key Words (Suggested by Authorhl 1 
Composites, Graphite/Epoxy ,Transports  
Aircraft  , Maintenance, F l igh t  Serv ice  
18. Distribution Statement 
Unclass i f ied  - Unlimited 
Subjec t  Category 24 


Flight service evaluation of advanced composite ailerons on the L-1011 transport aircraft

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