Who doesn’t want to cut costs?  Particularly in these times of supply chain stress, inventory holding costs rising, price increases, and the drive to do more with less as staff shortages bite.

How would you like to cut a cost in half AND do more with less?  Impossible you say?

Well, think again.  Device Technologies (DTi) has a simple, non-controversial component and process suggestion for any OEM that could save them $1 MILLION per year and make far better more efficient use of your production techs.

Here’s How DTi Saves OEMs Money:

Switch from the MS21266 nylon grommet edging and its required adhesive- to the higher performance Spring-Fast® M22529/2 grommet edging. It is simply a far better product that offers best-in-class performance.

Grommet edging is a simple product – it protects aircraft wiring from chafe.  Since the 1940’s the SOP has been to use a nylon grommet MS21266 and keep it in place with adhesive. I will walk you through the inherent issues that OEMs face with MS21266 that once you switch help drive the savings.  We know from working with clients that using Spring-Fast saves them at least 49% of their total install costs but that saving can go higher depending on your own shop labor rate.

applying grommet edging

How did we come up with $1 Million?

This $1m savings estimate is based on a trade study format with 3 key assumptions:

  • 300 aircraft per year,
  • 100 penetrations per aircraft
  • A burdened wrap rate of $130

Obviously, these probably don't tally with your internal numbers but call us and we’ll walk you through it. The savings summary is below. See Table 1 for the breakdown of the direct labor & material costs.

Aircraft /yearPenetrations/aircraftGrommets neededDirect Labor /Material Cost Per GrommetAnnual Cost
MS21266 Nylon30010030,000$54.62$1,638,625
TotalSAVINGS --> $1,040,650

M22529/2 is fully qualified as an FAA-approved replacement part and already has NAVAIR approval.

 Why the Savings Are So Significant

The designed-in features of the M22529/2 grommet drive a far lower direct labor install cost than MS21266

  • Snap-in-place installation without adhesive
  • Superior retentive strength without adhesive
  • Immediate wire/harness routing – no fixturing or cure time delays

An Operational Impact Far Greater Than Its Size

Grommets are small components but their EWIS impact is far larger than their size.

They protect aircraft wiring from chafe and abrasion.  In extreme cases chafe can cause dangerous arcing, sparking, and fires.  However, even before those more dangerous issues, chafe creates widespread problems even at relatively low levels.

NAVAIR data shows that when aircraft were designated as AOG (Aircraft on Ground) or NORS (Non-Operational Ready Status), the biggest single reason at 37% was wiring discrepancies due to chafe.

As a result, chafe is a significant drag on readiness, availability, & efficiency and will impact medium to long-term operational costs.  Operational reliability and performance are powerful selling points to end users.

This is older data but as MS21266 is used consistently there is no reason to assume these underlying trends have changed.

Legacy Grommet Issues

Our experience in aerospace and with the military has shown that the legacy glued nylon MS21266 caterpillar grommet has fundamental process issues:

  • Preparation and application involve a costly, labor-intensive and multi-step process.
  • Multiple items for application & safety have to be gathered in the preparation phase.
  • Edge preparation is required: light abrasion with Scotch-Brite and cleaning with IPA or an acetone wipe is needed to ensure proper glue adhesion.
  • The MS21266 grommet has no inherent retentive strength or static friction so is glued to the penetration using Pliobond –a single-stage, MEK solvent-based, air-cure adhesive. While Pliobond is considered a contact cement, in almost all cases, MS21266 requires “fixturing”-securing with pieces of masking tape- to hold it in place until the adhesive cures.
  • Any excess adhesive after curing has to be cleaned with a MEK solvent, cloths, and elbow grease.
  • Dis-bonding issues mean the work often has to be redone – adding to the cost of poor quality. Also, over time, the nylon and adhesive are more prone to failure from flight stresses and embrittlement

The glued nylon grommet was invented in the 1940s and while it was state-of-the-art for its time, technology has moved on from this slow, messy, and costly process.

Why M22529/2 Is A Better Choice

  • M22529/2 is a high-performance grommet that has a polymer coating on an ultra-thin CRES substrate that snaps into place with finger pressure. It has proven its performance across multiple aero platforms (see Appendix 2)
  • It is a caterpillar-style grommet with opposing finger-like castles that exert a compression force that creates static friction for retention without glue.
  • It has passed 20/20/20 G static load tests – even when 4 castles are removed to provide clearance for a p-clamp riveted clip used for select penetrations by some platforms.
  • M22529/2 virtually eliminates the large FOD footprint of shop consumables required for the glued nylon grommet – gloves, cheesecloth, IPA wipes, adhesive, tape, solvent, masks, etc.

Cost Breakdown

The pivotal data in the savings model are a comparison of the time and cost impact of the installation of MS21266 and M22529/2. See Table 1 for the detailed cost breakdown.

Installation Cost per grommet MS21266                               $54.62
Installation Cost per grommet M22529/2                              $19.93

These were generated by estimating the time taken for each operation needed to install the grommets and calculating the cost using the WRAP rate.  The time estimates are based on our extensive experience with many aerospace/military clients.  The lower number for M22529/2 is driven by its far simpler installation process and reduced production tech involvement.

Additional Savings Not Included in the Estimate

Scrap:  The model compares 12.75” strips, however in practice MS21266 –supplied only as precut strips- has to be cut to fit which means that for a 3″ penetration/9.4″ circumference, it yields 3.35″ or 26% of scrap. In contrast, M22529/2 is supplied on reels & cut to length with minimal scrap for a far higher yield.

Nylon vs. Teflon: The model assumes the use of 100% nylon grommets. However, if Teflon grommets are used the savings will increase as Teflon costs 10x to 28x ($3.50/$9.95) more than nylon per strip.

Consumables: MS21266 requires consumables of adhesive, IPA wipes, solvents, fixturing tape, gloves, masks & clean-up cloths. M22529/2 needs only IPA wipes. Fewer consumables yield less general overhead as well as a far smaller FOD footprint. Less to carry in means less to carry out/

Efficiency/Productivity Improvements: M22529/2 frees up tech time which can be allocated to other tasks.  With it you will save 17.2 minutes/grommet.  If the tech is fitting 100 grommets that is a saving of 28.7-man hours.  If you extrapolate that to 300 planes it comes to a saving of 8610 tech hours.  That is 4.13-man years.   How could this not be a strong contributor to efficiency, doing more with less and helping with any backlog reduction?

Aerospace Weight Comparison

In the past, some of DTi’s clients have expressed concerns that because Spring-Fast had a metal substrate it would immediately be ruled out because of weight.  However, we assured them that switching from MS21266 to NASM22529/2 has no weight penalty and the savings to be gained from such a simple low-tech, minimal change are significant.  And we proved it.

The Spring-Fast grommet is designed with a metal substrate and is fit for purpose without any additional product being needed.  However, nylon grommets have no inherent retentive strength so have to be glued into place so that they stay on the edge as explained earlier.  They need this secondary product -the adhesive- to perform their assigned task.

The methodology used to apply the adhesive to the nylon grommets varies by OEM.  As a result, it is a non-standard task with uncontrolled variability. However it is done, the adhesive adds to the weight of the nylon grommet and must be included in any weight comparison against the “glue-less” Spring-Fast.

Regular Validation

DTi does regular validation testing of the weight comparison.  DTi samples its Spring-Fast product and weighs it to make sure it is within spec. We also periodically apply adhesive to nylon grommets and use the recommended 3/16″ bead along one side of the 12.75″ grommet.  In our experience, this is very conservative as considerably more adhesive is used in practice which adds even more weight. We also use the Pliobond for the adhesive.  Note: CB200 -the other most commonly used adhesive- is 17.8% heavier than Pliobond.

Note also that if you are using MS21266 Teflon grommets (1T/2T/3T/4T) these weigh 89% to 107% more than their nylon versions (1N/2N/3N/4N) so they will be much heavier than their nylon counterparts even without adhesive.

The key findings from this weight validation testing are as follows:

  1. After installation, Spring-Fast grommets on average weigh 12.8% less than the nylon MS21266 equivalents and the applied adhesive.  This surprises most people as they often forget about the adhesive.
  2. In reality, the absolute weight of either style of grommet is negligible. Weights range from 0.015 to 0.026 lbs. per grommet.  100 grommets would weigh ~2.6 lbs.  However, weight is such an important factor for flying that we wanted to prove it to clients who raise it as an issue.  Most OEMs are enthusiastic about the savings in weight and install cost.

Below are the backup charts and tables so that you can see the methodology for the savings estimates.  We would be happy to discuss this with you. Your numbers will likely be different for example many companies have a shop labor rate higher than the $130/hr we used.

DTi knows it has a better grommet “mousetrap” It saves you time & money and yields a higher quality, more aesthetic result.

New Developments

Device Technologies’ (DTi) mission is to help OEMs improve their efficiency and profitability by providing components that facilitate fast and efficient manufacturing, maintenance, and refits.  This is particularly important in this current environment of labor shortages and trying to do more with less.

Our mission is to develop new products and seek out industry approvals and certifications so that the new products always have the appropriate testing, permissions, and certifications that meet OEM's needs.

MilSpec for Flanged Edges

DTi received mil-spec and FAA approval for M22529/3 in late Q3 2023.  This new product complements DTi’s two current FAA-approved mil-spec grommets Spring-Fast® M22529/1 (M/1) and M22529/2 (M/2).  M/1 and M/2 are for 2-axis applications like straight edges without any edge treatment. M22529/3 accommodates roll-formed and flanged penetrations by offering 3-axis flexibility.

It rounds out the product range as flanged lightening holes and penetrations are a significant part of the wire routing in many older -and frequently retrofitted- aircraft.

In keeping with our mission, DTi has a pending PMA (Parts Manufacturer Approval) which, once granted, is official recognition by the FAA that the Spring-Fast product is as good if not better than existing components. This will facilitate its use in the field.

This PMA will greatly aid DTi’s penetration into both the MRO market and retrofitting.  It may not have been specified originally but it can now be used freely.  We plan to insert it into announcements and manuals so that it can be easily used in place of the old messy and costly nylon grommet.

Other Considerations- Greener and Safer Product

Spring-Fast is applied with finger pressure, not glue.  This means workers are not exposed to VOCs from the adhesive or clean-up solvents that are routinely used.  This often requires ventilation for techs working in the area with masks and fans being used to protect the workers and to minimize their VOC exposure.  Spring-Fast avoids these health and safety and possible hazmat issues.

We would happily walk you through the spreadsheet and see how high we can get your savings.

In the meantime, if you want to see for yourself please request some free samples here.

Table 1        Breakdown of Installation Costs of MS21266 and M22529/2

MS21266 NylonMS21266 NylonM22529/2M22529/2
OperationTime/minsCost $
Time/minsCost $
Sub Operation set up
Gather all safety equipment5$10.852$4.34
Gather all materials grommet/glue etc5$10.852$4.34
Total set up time/$10$21.704$8.68
Batch size for amortization
Amortized batch costs (sub op above)
Measure/cut to fit3$6.513$6.51
Prefit /trim as needed1$2.171$2.17
Deburr/sand edge1$2.1700
Clean with MEK/IPA wipe2$4.341$2.17
Cut 8 pieces of tape for fixturing3$6.5100
Apply adhesive to edge5$10.8500
Apply Grommet -apply tape5$10.851$2.17
Remove tape-clean up MEK
Inspect fit/finish
Labor cost25$54.277.8$16.93
Grommet cost$0.35$3.00
Total Costs$54.62$19.93
Wrap Rate $130/hr

Appendix 2        Proven Performance on Many Platforms

M22529 has proven performance on a wide range of military and commercial platforms which have high performance requirements.

Sikorsky UH-60M                                                                M22529/2
Grumman E2C Hawkeye                                                    M22529/2
EADS Eurofighter Typhoon                                                 M22529/2
Lockheed US101                                                                M22529/2
Boeing T 38 Trainer                                                            M22529/2
Boeing CH-46                                                                     M22529/2
Boeing CH-47 Chinook                                                       M22529/2
Boeing C17 Transport                                                         M22529/2
Sikorsky CH-53 Super Stallion                                            M22529/2
Eurocopter Sea Lynx                                                           M22529/2
Leonardo A109 Power -1R-100                                           M22529/2
US Coast Guard H-65 Dauphin                                            M22529/2

Military Tactical Applications
BAE-Ohio M1114 Humvee                                                  M22529/2
BAE Systems Land & Armaments ILAV                               M22529/2
General Dynamics IMSE                                                     M22529/2

Civil Aircraft
Pilatus PC 12                                                                       M22529/2
Sukhoi Superjet 100                                                            M22529/2
Adam Aircraft A700 Adamjet                                               M22529/2
Adam Aircraft A500                                                              M22529/2
Quest Kodiak S/N 001                                                          M22529/2
Eclipse Aviation 500 VLJ                                                     M22529/2

Also available through a licensed distributor like Aircraft Spruce