**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page i 

# FAA discussion of the cargo testing as described in the final rule comments

Supplement to Docket No. FAA

- 2014

- 0780

Prepared by:

Steven Fox, P.E. Federal Aviation Administration Senior Aerospace Engineer Airframe Branch, ANM

- 120S Seattle Aircraft Certification Office Work (425) 917

- 6425**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page ii 

## General i ssues related to the industry testing and issues raised by the commenters

As stated in t he final rule preamble :
Opposition to NPRM (79 FR 71037, December 1, 2014): Inadequate Testing

Cargo Airline Association, Atlas Air, NACA, IATA, Kalitta, and the Michigan Senate criticized the tests discussed in the NPRM (79 FR 71037, December 1, 2014) that confirmed the FAA’s de termination that loading containers in the offset position is an unsafe condition, arguing they were unrealistic or inconclusive. In general, the commenters claimed that the tests used configurations of intermodal containers and their restraints that are d ifferent from those used in service and applied pass

- fail criteria that were unnecessarily stringent.

We do not agree that the tests were unrealistic or inadequate. A detailed discussion of the commenters’ technical concerns regarding the tests is included in the AD docket.

========================================== ======= ====================

The followin g is a discussion of the testing methods used by the industry team of eng ineers from Atlas Air, Kalitta A ir (Kalitta)

, United Parcel Service ( UPS )

, and Boeing (hereafter referred to as the industry team)

. This discussion is limited to aspects of the testing necessary to address issues raised by commenters, and is not intended to be a comprehensive discussion of the relevant tests. Also included is an FAA response to the specific concerns of several commenters about the validity of the testing

.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page iii 

### Contents Background

................................ ................................ ................................ ................................ ..... 1 What is a ULD and how is it certified for use on the Boeing Model 747?

................................ . 1

What is the “Offset Method” for loading intermodal containers?

................................ .............. 1 What prompted the industry team to start testing?

................................ ................................ ..... 1 What are some of the requirements for showing compliance?

................................ ................... 2 What are the CG effects used for testing?

................................ ................................ .................. 3 What is the method to develop a test configuration to assess the CG for critical loading conditions for cargo inside the intermodal container?

................................ ................................ 5

What was learned from the baseline testing of an empty intermodal container offset and restrained only by a net to a pallet in Oscoda, Michigan?

................................ .......................... 7

What Further Testi ng Was Done?

................................ ................................ ............................... 7

Comments on the rule

................................ ................................ ................................ ................... 11 The lateral CG testing method

................................ ................................ ................................ .. 11 Lack of testing an offset intermodal container strapped directly to the airplane

...................... 11 Use of too many straps in the Arlington testing

................................ ................................ ....... 12 Testing nonconformance to NAS 3610

................................ ................................ ..................... 12 The effect of shifting comparisons

................................ ................................ ........................... 12 Testing not reflective of typical airline loading

................................ ................................ ........ 13 Lack of consideration for energy

- absorbing straps and nets during testing

............................. 13 Test results not made public permitting adequate comments

................................ ................... 14**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 1 

## Background

What is a ULD and how is it certified for use on the Boeing Model 747?

As discussed in the final rule preamble , t he Boeing 747 cargo airplanes are equipped with a cargo loading system, which is part of the airplane’s type design and consists of roller trays, guides, latches, and locks that restrain the cargo to the airplane for flight loads. A u nit l oad d evice (ULD) is a device for grouping and re s t r aining cargo for transit. The types of ULDs permitted by the Boeing weight and balance manuals ( WBMs ) meet the standards of National Aerospace Standard (NAS) 3610 (“Cargo Unit Load Devices

– Specification For”). In accordance with NAS 3610, the ULD pallet

- net combination rest rains the cargo to the pallet. The airplane guides, latches, and locks restra in the pallet to the airplane.

The final rule preamble has a comp lete discussion of this topic. NAS 3610 defines the configurations and test requirements for these permitted ULDs. In the case of a netted pallet, NAS 3610 prescribes applied loads that the netted pallet must be capable of withstand ing and the locations ar ound the perimeter of the pallet where the restraints are to be used

. NAS 3610 also prescribe s test parameters for the specified limits for the c enter of g ravity (CG) ( Section 3.10.1) to be used for the testing. These NAS 3610 configurations, load cases, a nd CG limits were used by Boeing to design the capability of the Boeing Model 747 cargo loading system (CLS) and to develop the requir e d instructions in the Boeing Model 747 WBM s for loading these ULDs. The final rule preamble discuss es this subject

, including that an intermodal container does not meet the requirements of NAS 3610 and is not allowed as a certified ULD under the Boeing WBMs

.

What is the “ Offset Method” for l oading i ntermodal c ontainers?

The FAA has become aware that some operators, bot h domestic and foreign, are not loading intermodal containers in the center of the airplane, but rather in the standard left and right pallet positions. When loaded in this manner, t he 8

- foot, 6

- inch, height of the intermodal container interferes with the fuselage, so some operators have been transporting these intermodal containers shifted inboard

, off of the FAA

- approved TSO pallets

, and attached to the pallet only with a net and/or straps. This method of transport is referred to as the “offset method.” T he practice of offsetting the intermodal containers results in the certified pallet

- net combination having slack in the net by the amount of the offset.

What prompted the industry team to start testing?

The Seattle Aircraft Certification Offic e (SACO) firs t became aware of offset intermodal container s bei ng transported on Boeing 747s in September 2013, and reached preliminary conclusions that the method was non compliant and unsafe in October 2013. The SACO then issued a memo randum concerning this practice o n November 8, 2013. A copy of this memo was submitted to the docket by Kalitta as background ( Kalitta comment, Appendix A )

. This**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 2 prompted the industry to perform tests to show that using the offset method could be shown to comply with the applicable airworthiness standards.

What are some of the requirements for showing compliance?

As discussed in the November 8, 2013

, SACO memorandum

, t he intermodal container loaded using the offset method does not comply with the Boeing WBM s . The intermodal container loaded using the offset method does not comply with NAS 3610 because of slack in the net. Th e offset method precludes “ adequately encompass [ing] the cargo ” and does not provide for “ proper support and restraint of the cargo ” ( NAS 3610 par a graph 3.4). NAS 3610 has no provisions to meet the standard by supplementing the required net with straps. Demonstrating that the intermodal container complies with NAS 3610 is not possible

, for the reasons stated above.

As discussed in the final rule preamble , carry ing i ntermodal container s u sing the offset method would require either restraining the container s directly to the airplane , which is the only currently approved method, or changing the type certificate with a n associated WBM supplement shown to comply with the applicable airworthiness standards

.

The industry team attempt ed to demonstrate that th e offset practice could be shown to be compliant with the applicable airworthiness standards : those listed on the Type Certificate Data sheet fo r the Boeing 747 (A20WE)

.

Some of these requirements for showing compliance are restated be low:

§25.301 Loads.

. . . (b) Unless otherwise provided, the specified air, ground, and water loads must be placed in equilibrium with inertia forces, considering each item of mass in the airplane. These loads must be distributed to conservatively approximate or closely represent actual conditions. Methods used to determine load intensities and distribution must be validated by flight load measurement unless the met hods used for determining these loading conditions are shown to be reliable.

. . . §25.305 Strength and deformation.

(a) The structure must be able to support limit loads without detrimental permanent deformation. At any load up to limit loads, the defor mation may not interfere with safe operation.

(b) The structure must be able to support ultimate loads without failure for at least 3 seconds. However, when proof of strength is shown by dynamic tests simulating actual load conditions, the 3

- second limit does not apply. Static tests conducted to ultimate load must include the ultimate deflections and ultimate deformation induced by the loading. When analytical methods are used to show compliance with the ultimate load strength requirements, it must be show n that

—**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 3 (1) The effects of deformation are not significant;

. . . §25.307 Proof of structure.

(a) Compliance with the strength and deformation requirements of this subpart must be shown for each critical loading condition. Structural analysis may be used only if the structure conforms to that for which experience has shown this method to be reliable. I n other cases, substantiating tests must be made to load levels that are sufficient to verify structural behavior up to loads specified in §25.305

.

. . .

For the intermodal container restrained using the offset method

, an applicant must show that the inten ded payload will remain attached to the airplane’s cargo loading system during all loads specified in subpart C of Title 14 Code of Federal Regulations ( 14 CFR ) part 25 so that the container can not impact the fuselage frames , which c ould cause them to fail , contrary to the requirement of 14 CFR 25.305(b)(1). These loads must be applied in all directions

– that is, vertical, lateral, and longitudinal

– because airplanes may encounter all of these loads during operations. For showing compliance, i n this case, where experience has not shown analysis to be reliable, 14 CFR 25.307(a) requires substantiating test s

.
As stated in 14 CFR 25.301(b), t hese loads must be distributed to “ conservatively approximate or closely represent actual conditions. ” In this case, c losely represent ing actual conditions would require testing each individual intermodal container loaded with the contents that are to be transported on each flight. Then for each flight flown, the actual cargo (container and contents) would have to conform to those configurations tested and certified. This is impracti cal

. Therefore

, typically, applicants ch o ose to perform tests using a “ conservatively approximate ” method.

The intended total gross weight of the intermodal container loaded using the offset me thod on a pallet can readily be determined for certification. T he distribution of that weight inside the intermodal container must also be investigated because the CG of the cargo within the container can have a significant effect on the applied loads at the locations on the airplane where the container is restrained

. This change in location of the CG could result in failures of the cargo loading system ’s restraints

. An industry standard procedure for conservatively approximating these effects is to test l oading ob j ect s with approximately uniform density within the container, and then vary the locations of the object s to produce a change in the CG for the intended certifiable weights.

What are the CG effects used for testing ?

For certification testing, t he CG for the cargo used in testing must vary in the lateral, longitudinal

, and vertical directions of the airplane to address a range of realistic flight scenarios

.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 4 Different centers of gravity are critical for different flight load cases (14 CFR 25.307(b)) and must be addressed in the testing

.

There are two different CG effects that must be addressed in testing intermodal containers loaded using the offset method:

(1) t he airline’s offset placement of the int ermodal container 9 inch es inboard on the pallet

, whic h creates a 9

- inch lateral shift in the CG for the intermodal container itself and its cargo ; and

(2) the unknown and potentially shifting CG of the cargo inside the intermodal container

.

These e ffects must be considered in combination

. Because the intermodal containers are typically locked before the operators receive them

, operators ha ve no means to determine, or control during flight , the CG of the cargo within the locked container.

Figure 1 : Photograph showing shifted cargo during transport , which can ch ange the CG locations**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 5 Figure 2 : Photo graph show ing carriage of liquid cargo , which can move within the plastic containers, changing the CG during flight

What is the method to develop a test configuration to assess the CG for critical loading conditions for cargo ins ide the intermodal container?

Since operators ha ve no ability to control the cargo inside the locked intermodal container

, it is nearly impossible to predict the CG of those contents

. A simple method to address this uncertainty is to test using a triangular shaped distribution of cargo. This is analogous to a pile of gravel inside the intermodal container sloped to the top on one side and tapering off to the bottom on the other. The FAA has approved the use of this m ethod.

The diagram below shows the location of the CG ( ⊕ inside the triangle) for this triangular

shaped assumed cargo as defined by simple plane geometry

.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 6 Figure 3 : Lo cation of the CG ( the ⊕ inside the triangle) for triangular

- shaped cargo

When the cargo is distributed in the shape of a right triangle, the CG is one

- third the distance from the right angle

. 1 In this diagram, the base of the triangle is the 8

- foot widt h of the intermodal container. In an 8

- foot wide intermodal container

, t he C G of uniformly distributed cargo is in the center of the container, 48 inches from the edges of the container

. The triangular distribution of cargo results in a CG that is 16 inches from the center of the container (the CG of cargo uniformly distribut ed in an 8

- foot wide intermodal container )

.

1 Timoshenk o, Stephen, and James M. Gere. “ Appendix B, Properties of Plane Areas. ” Mechanics of Materials. New York: Van Nostr and Reinhold, 1972. 503. Print.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 7

Width of the intermodal 8 f ee t x 12 inches/f oo t = 96 inches

CG for uniform distribution 1⁄2 of 96 inches = 48 inches

CG for triangular distribution 1⁄3 of 96 inches = 32 inches Triangular d istribution distance from center 48 inches

– 32 inches = 16 inches

When the two effects described previously are combined, the resulting shift of the CG is 25 inches (9 inches for the offset of the container, and 16 inches for the potential shift of the cargo inside the container)

. What was learned from the baseline testing of an empty intermodal container offset and restrained only by a net to a pallet in Oscoda , Michigan?

One of the first tests explored by Kalitta in Oscoda, Michigan, in late 2013 involved restrain ing

an empty in termodal container loaded using the offset method and using onl y the restraints defined in NAS 3610 : a pallet and net combin ation. Again, t he restraints described in NAS 3610 do not have provisions for additional straps ; in fact, the word “strap” does not appear in the document. Also, the CG of an empty intermodal container is in the center of the container, so this test did not address the seco nd effect discussed previously.

Kalitta’s test was a lateral outboard test. This test simulated the airpl ane encountering a gust on the side of the airplane so that , because of its inertia, the offset container shifted outboard. This test involve d gradually tilting the offset container, restrained to the pallet only by a net, in a test rig to an angle that im pose d a side load on the container that is comparable to the gust load referenced in the airworthiness standards. Thi s test failed early on, well before the required side load was achieved. The test demonstrated that the slack in the net introduced underne ath the offset intermodal container on the inboard side renders the net ineffective

. Based on this failure, the offset container restrained using the pallet

- net combination described in NAS 3610 was shown not to co mply with 14 CFR 25.305(b)(1). Similarly, the test demonstrated that the requirement for “proper support and restraint of the cargo” (NAS 36 10 par a graph 3.4) was not

met.

Although the FAA , Boeing, and the other airline engineers had not participated in this Kalitta testing, the FAA, Boeing

, and the other airline engineers accepted the test failure results as shown by Kalitta. T he industry team subsequently abandoned t he use of the pallet

- net combination for all future testing referenced in the preamble of the final rule

. The FAA agreed with the industry team to delete the ineff ective net for future testing. The result of this decision is that the NAS 3610 standard was no longer applicable for these tests.

What Further Testin g Was Done?

Two more sets of test s of offset intermodal containers were accomplished by an industry team consisting of engineers f r om Atlas Air, Boeing, Kalitta , and UPS. O ne set of tests was performed in March 2014, in Oscoda

, Michigan, and another in May 2014 at Arlington, Washington. These**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 8 tests explore d the use of car go straps to restrain the offset intermodal container to a pallet without the net required by NAS 3610 and without restraints from the container to the airplane itself (the cargo loading system restrained the pallet to the airplane)

. The purpose of these t ests was to determine whether using straps to restrain the offset intermodal container only to a pallet could be shown to comply with the applicable airworthiness requirements.

March 2014 t esting in Oscoda , Michigan

The industry team chose to address the C G effect of the cargo inside the locked intermodal container using the industry practice described above as the triangular distribution of cargo. For the testing in Oscoda, Michigan

, the two CG effects (9 plus 16 inches) add ed up to 25 inches

. This is docu mented in the industry test plan prepared by Kalitta in Report 13

- 0160 ER, Revision 3, Section 2.2:

The test weight Center of Gravity (CG) within the ISO 1CC container will be adjusted to accommodate a lateral CG shift up to 16 inches. The longitudinal and vertical CG locations are unplanned, but will be determined during testing. The ISO 1CC container shall then be restrained on the TSO

- C90 PGA pallet with the 16 inch CG shift oriented in the same direction as the 9 inch lateral shift of the container on th e pallet. The final configuration of weight, center of gravity, shoring and restraint straps will be documented in a final test report which will contain all of the data results from the testing o utlined within in the document.

After several test failures, the industry team reconsidered using the test method involving the triangular distribution of cargo and elected to attempt a vertical load test with NO CG shift of the

cargo wi thin the intermodal container. A vertical load test simulates a gust that pushe s the airplane down, so that, because of its inertia, the offset container shifts upward. Only the CG effect of offset ting the container was tested . The objective of this test was to better understand

, by comparison, the effects of the CG distribution of c argo inside the container . This test failed by breaking the vertical locks of the cargo loading system , result ing in the container being

un restrained . After this test failure, the industry team in Oscoda ceased further testing until new test procedures wer e developed.

As discussed previously, for certification testing, the CG for the cargo used in testing must vary in the lateral, longitudinal, and vertical directions of the airplane to address a range o f realistic flight scenarios. The required l ongitudina l and vertical CG shifts used in the Oscoda testing were

not adequately tested for this purpose because the testing was incomplete when test s w ere halted after multiple failures. The industry team did not create a report documenting the failed results.

May 2014 testing in Arlington, Washing ton

T he industry team conducted a nother set of tests of offset containers that also failed. B ecause intermodal containers are typically locked when operators receive them, operators cannot determ i ne or adjust the CG of th eir contents. To address this, t he industry team decided to attempt to develop a method to predict the direction of the deviation from the container’s centerline of the lateral CG of the cargo inside the container

. The industry team balance d the**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 9 intermodal container on a fulcrum located along the longitud in al center line of the intermodal container and document ed whether the intermodal container tipped, and in which direction

. This direction c ould then be placarded on the container as “outboard” on the airplane for loading. This method could be used to counteract the CG effect of the offset container and reduce the combined CG effect s discussed previously

. When the industry team used this method to perform a vertical load test of an offset intermodal

con tainer, the vertical locks of the cargo loading system failed. The reason for the failure wa s that the offset of the container result ed in slack in the straps located in the center of the container. Because of this slack, the straps located at the ends of the container carried most of the load imposed by restraining the container to the pallet . (See F igure s 4

, 5 , and 6 .) The locks that failed first were those that were closest to the end of the pallet where these straps were attached. These failures resulte d in cascading failures of adjacent locks. In flight, this would result in the container be com ing unrestrained.

The effects of the cargo shifting in flight inside the intermodal container were not explored. Further, the required range of changes in the lon gitudinal and vertical centers of gravity was not inve stigated by the industry team. After the vertical testing failures

, the industry team ele cted to stop further testing. The industry team did not create a report documenting the failed results.

Figure 4: Computer drawing showing intermodal container offset on a pallet and restrained by straps to the pallet**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 10 Figure 5 : Photo taken in Oscoda, Michigan, showing intermodal container strapped to a pallet , and inverted to prepare for vertical testing

Figure 6 : Photo taken in Arlington, Washington , showing intermodal container strap ped to a pallet , and inverted to prepare for vertical testing**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 11 

## Comments on the rule

The l ateral CG testing method

Several commenters (Atlas Air

, Cargo Airline Association ( CA A )

, and Kalitta) asserted that the

test by the industry team in March 2014, in Oscoda, Michigan

, used a container that was of fset on a pallet, with a CG shift exceeding the limit allowed by the WBM by nearly three times

, which caused a grossly imbalanced load, which then caused the test to fail. The WBM limits the CG lateral deviation to 10 percent of the width of the pallet (9.6 inches). Kalitta stated that the load packed inside the container was actually 16 inches off

- center, and the container was set nine inches off the pallet. Kalit t a stated that the total CG deviation was, therefore, 25 inches.

The commenters are correct that the test used a 25

- inch lateral CG offset ; however

, they fail to acknowledge the combined e ffect described above resulting from the carriage of the offset intermodal container with an unknown CG of the contents of the container

. T he testing did use the industry team’s CG deviation as defined in the team’s test plan in its attempt to show that this configuration complies with the airworthiness standards, even though it exceeds the limits specified in the WBM. B ut the vertical tes t failure in Oscoda occurred during a test of a container with the CG of its contents loc ated in the center of the container. Therefore, the second CG effect was eliminated

.

Lack of t esting an offset intermodal container strapped directly to the airplane

The CAA stated that the Arlington test ing was not conducted with the intermodal container configured within the CG allowable limits of TSO C

- 90 and did not use the original strap configuration tested in Oscoda

. The CAA and NACA also stated that the test did not consider the configuration actually used by the airlines. For example, there was never a test conducted with the ULD tied directly to the aircraft.

The CAA ’s conclusions are incorrect. By design, the Arlington test was not conducted in accordance with the TSO standard and did not use the original strap configuration tested in Oscoda be cause the industry team was attempting to show that it is possible to load offset containers in a manner that complies with the applicable airworthiness standards, even though they do not comply with the TSO

. As discussed previously, the strap configur atio n tested in Oscoda failed. No testing was conducted with the ULD tied directly to the aircraft because that is not the retention method the industry team was attempting to show compliant . The industry team was attempting to substantiate its desired configu ration of an offset intermodal container restrained only to a pallet that, in turn, is restrained only by the carg o loading system

. The industry team did not propose to test the configuration that operators may have previously used

.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 12 Use of too many straps in t he Arlington testing

Kalitta asserted that t he test in Arlington used 65 percent more cargo straps ( a total of 96) than

are normally used ( 58 ), which caused local areas of higher stress that caused the pallet to bend and the cargo loading system locks to break.

The commenter is correct regarding the number of straps used

. However, the failure of the locks was not attributable to the number of straps. As discussed previously, the locking failure was caused by overloading of the carg o loading system locks located near the corners of the pallet ; straps in the cen ter of the container were unable to perform their function of carrying loads because of slack in those straps

. Testing nonconformance to NAS 3610

Th re e commenters (CAA, Kalitta

, and the Michigan Senate) stated that the first test in Oscoda

was not performed in accordance with the NAS 3610/AS36100 2 s tandards, which govern the loading of ULDs , and the results are, therefore, invalid

.

The commenter s are correct that the tests were not performed in accordance with the referenced standards

. As described in the background section of this document, t he intermodal container loaded using the offset method is not a ULD as defined in NAS 3610

. Therefore

, the testing

req uirements for a ULD are not applicable

. The industry team chose not to test in accordance with the NAS 3610/AS36100 standards

, because the intermodal container would have to be concentrically loaded on the pallet and restrained only with the corresponding net. The use of straps to restrain cargo to the pallet is not permitted in NAS 3610

. The objective of the industry team’s testing was to show that using the offset intermodal container complies with the applicable regulations descri bed in the B ackground section of this document

. This practice could then be the basis for a Supplemental Type Certificate (STC) Weight and Balance supplement

. As discussed previously, the testing was unsuccessful.

The effect of shifting comparisons

The CAA asserted that the excessive shifting of the offset intermodal containers was not compared to the shifting of an intermodal container restrained by a certified pallet

- net ULD. The CAA further stated that Kalitta has performed such additional testing, and t he shifting of cargo restrained by a net far exceeds that of the same cargo also restrained by straps. The CAA asserted that t he strap configuration is superior to the net configuration with respect to shifting and is therefore a preferable, safer method for transporting intermodal containers than using just nets alone.

The FAA disagrees with the CAA’s assertions

. As discussed in the NPRM, a pallet

- net combinati on restraining a concentrically loaded intermodal co ntainer can be located only on the

2 AS36100 is a later version of NAS 3610.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 13 centerline of the airplane because it would otherwise interfere with the fuselage frames. At this location, the container is at least four feet from the fuselage frames. The testing of offset intermodal containers was per formed to determine whether intermodal containers could be loaded using the offset method to the left or right of the centerline and still enable the airplane to meet the applicable airworthiness standards. At these locations, much smaller shifting could

r esult in the container impacting the fuselage frames.

T esting not reflective of typical airline loading

Several commenters ( Atlas, CAA, Kalitta, and the Michigan Senate) contend ed that t he FAA has reached conclusions from the cargo load te sting conducted l ast year based on atypical loading of the cargo

.

The commenters are in correct. As discussed in the B ackground section of this document, the industry team ’s testing was intended to demonstrate that loading offset intermodal containers can be shown to comply with the applicable airworthiness standards , which require that testing “conservatively approximate” actual conditions

. The industry team chose the weight of the cargo inside the container to be tested based on the team’s desired payloads

. The team determ ined t he CG deviation for that cargo by using the triang u l ar distribution method because the actual loading of the locked containers is uncontrolled

.

Lack of consideration for energy - absorbing straps and nets during testing

IATA asserted that the loads tha t might impact the fuselage frames would be reduced by the energy absorbed by the net, thus the impact dam a ge to the fuselage frames would be reduced. IATA further stated that i n

- flight observations confirm that the net acts as a de facto braking device wh ile it absorbs energy through elongation, so that irrespective of the type of cargo carried, it sometimes comes in soft contact with the fuselage, but never to impact. IATA also stated that c argo l oading s ystem (CLS) failure is not specified a s a case for ULD certification, which considers only ULD failure

, and that a CLS failure certainly ju stifies complete investigation.

The FAA found that IAT A provided no data to substantiate its claims and no evidence of how much energy would be absorbed by the net elongation such that it would eliminate the unsafe condition. It is unknown whether IATA conducted i n

- flight observations

, including observations of any offset intermodal container configurations. Further, the offset method introduces slack in the net
, which is not accounted for in NAS 3610 ULD testing. A ny reduction in energy absorbed by the net would occur only after the intermodal container shifted sufficiently to eliminate the slack

. Following the first test failure in Oscoda, t he industry team determined that the slack in the

net was so great that the net was ineffective, and the team did not use the net in later testing. In all vertical tests the industry team completed, the cargo loading system vertical locks f ailed, which result ed in the off set intermodal container becom ing unrestrained . This is unsafe.**Docket No. FAA 2014 0780 FAA Discussion of Offset Intermodal Container Testing** 

July 9, 2015 Page 14 T est results not made public permitting adequate comments

IATA commented that since the test results were not made public, IATA did not have full opportunity to review and comment.

As noted previously, the industry team did not document the failed testing in a test report; therefore, there is no test report to make public. However, IATA represents two of the industry team members, Atlas Air and UPS. Additional information regarding the tests may be available from them.