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                                                                 Exhibit 4.1.4  

                             SUPPLEMENTAL INDENTURE


         SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated as of
January 25, 1999, among Empire Air Systems, Inc. a New York Corporation (the
"Guaranteeing Subsidiary"), a subsidiary of Numatics, Incorporated (or its
permitted successor), a Michigan corporation (the "Company"), the other
Guarantors (as defined in the Indenture referred to herein) and First Trust
National Association, as trustee under the indenture referred to below (the
"Trustee").

                               W I T N E S S E T H

         WHEREAS, the Company has heretofore executed and delivered to the
Trustee an indenture (the "Indenture"), dated as of March 23, 1998 providing for
the issuance of an aggregate principal amount of up to $215,000,000 of 9-5/8%
Senior Subordinated Notes due 2008 (the "Notes");

         WHEREAS, the Indenture provides that under certain circumstances the
Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental
indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally
guarantee all of the Company's Obligations under the Notes and the Indenture on
the terms and conditions set forth herein (the "Subsidiary Guarantee"); and

         WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is
authorized to execute and deliver this Supplemental Indenture.

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guaranteeing Subsidiary and the Trustee mutually covenant and agree for the
equal and ratable benefit of the Holders of the Notes as follows:

         1. Capitalized Terms.  Capitalized terms used herein without definition
shall have the meanings assigned to them in the Indenture.

         2. Agreement to Guarantee. The Guaranteeing Subsidiary hereby agrees as
follows:

                  (a) Along with all Guarantors named in the Indenture, to
         jointly and severally Guarantee to each Holder of a Note authenticated
         and delivered by the Trustee and to the Trustee and its successors and
         assigns, irrespective of the validity and enforceability of the
         Indenture, the Notes or the obligations of the Company hereunder or
         thereunder, that:

                           (i) the principal of and interest on the Notes will
                  be promptly paid in full when due whether at maturity, by
                  acceleration, redemption or

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                  otherwise, and interest on the overdue principal of and
                  interest on the Notes, if any, if lawful, and all other
                  obligations of the Company to the Holders or the Trustee
                  hereunder or thereunder will be promptly paid in full or
                  performed, all in accordance with the terms hereof and
                  thereof; and

                           (ii) in case of any extension of time of payment or
                  renewal of any Notes or any of such other obligations, that
                  same will be promptly paid in full when due or performed in
                  accordance with the terms of the extension or renewal, whether
                  at stated maturity, by acceleration or otherwise. Failing
                  payment when due of any amount so guaranteed or any
                  performance so guaranteed for whatever reason, the Guarantors
                  shall be jointly and severally obligated to pay the same
                  immediately.

                  (b) The obligations hereunder shall be unconditional,
         irrespective of the validity, regularity or enforceability of the Notes
         or the Indenture, the absence of any action to enforce the same, any
         waiver or consent by any Holder of the Notes with respect to any
         provisions hereof or thereof, the recovery of any judgment against the
         Company, any action to enforce the same or any other circumstance which
         might otherwise constitute a legal or equitable discharge or defense of
         a guarantor.

                  (c) The following is hereby waived: diligence presentment,
         demand of payment filing of claims with a court in the event of
         insolvency or bankruptcy of the Company, any right to require a
         proceeding first against the Company, protest, notice and all demands
         whatsoever.

                  (d) This Subsidiary Guarantee shall not be discharged except
         by complete performance of the obligations contained in the Notes and
         the Indenture.

                  (e) If any Holder or the Trustee is required by any court or
         otherwise to return to the Company, the Guarantors, or any Custodian,
         Trustee, liquidator or other similar official acting in relation to
         either the Company or the Guarantors, any amount paid by either to the
         Trustee or such Holder, this Subsidiary Guarantee, to the extent
         theretofore discharged, shall be reinstated in full force and effect.

                  (f) The Guaranteeing Subsidiary shall not be entitled to any
         right of subrogation in relation to the Holders in respect of any
         obligations guaranteed hereby until payment in full of all obligations
         guaranteed hereby.

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                  (g) As between the Guarantors, on the one hand, and the
         Holders and the Trustee, on the other hand, (x) the maturity of the
         obligations guaranteed hereby may be accelerated as provided in Article
         VI of the Indenture for the purposes of this Subsidiary Guarantee,
         notwithstanding any stay, injunction or other prohibition preventing
         such acceleration in respect of the obligations guaranteed hereby, and
         (y) in the event of any declaration of acceleration of such obligations
         as provided in Article VI of the Indenture such obligations (whether or
         not due and payable) shall forthwith become due and payable by the
         Guarantors for the purpose of this Subsidiary Guarantee.

                  (h) The Guarantors shall have the right to seek contribution
         from any non-paying Guarantor so long as the exercise of such right
         does not impair the rights of the Holders under the Subsidiary
         Guarantee.

                  (i) Pursuant to Section 11.03 of the Indenture, after giving
         effect to any maximum amount and any other contingent and fixed
         liabilities that are relevant under any applicable Bankruptcy or
         fraudulent conveyance laws, and, to the extent relevant, after giving
         effect to any collections from, rights to receive contribution from or
         payments made by or on behalf of any other Guarantor in respect of the
         obligations of such other Guarantor under Article XI of the Indenture,
         the Subsidiary Guarantee shall not result in the obligations of such
         Guarantor under its Subsidiary Guarantee constituting a fraudulent
         transfer or conveyance or being improper or prohibited under applicable
         state law.

         3. Execution and Delivery. Each Guaranteeing Subsidiary agrees that the
Note Guarantees shall remain in full force and effect notwithstanding any
failure to endorse on each Note a notation of such Subsidiary Guarantee.

         4.       Guaranteeing Subsidiary May Consolidate Etc. on Certain Terms.

                  (a) The Guaranteeing Subsidiary may not consolidate with or
         merge with or into (whether or not such Guarantor is the surviving
         Person) another corporation, Person or entity whether or not affiliated
         with such Guarantor unless:

                           (i) subject to Section 11.05 of the Indenture, the
                  Person formed by or surviving any such consolidation or merger
                  (if other than a Guarantor or the Company) unconditionally
                  assumes all the obligations of such Guarantor, pursuant to a
                  supplemental indenture in form and substance reasonably
                  satisfactory to the Trustee, under the Notes, the Indenture
                  and the Subsidiary Guarantee on the terms set forth herein or
                  therein; and

                           (ii) immediately after giving effect to such
                  transaction, no Default or Event of Default exists.

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                  (b) In case of any such consolidation, merger, sale or
         conveyance and upon the assumption by the successor corporation, by
         supplemental indenture, executed and delivered to the Trustee and
         satisfactory in form to the Trustee, of the Subsidiary Guarantee
         endorsed upon the Notes and the due and punctual performance of all of
         the covenants and conditions of the Indenture to be performed by the
         Guarantor, such successor corporation shall succeed to and be
         substituted for the Guarantor with the same effect as if it had been
         named herein as a Guarantor. Such successor corporation thereupon may
         cause to be signed any or all of the Subsidiary Guarantees to be
         endorsed upon all of the Notes issuable hereunder which theretofore
         shall not have been signed by the Company and delivered to the Trustee.
         All the Subsidiary Guarantees so issued shall in all respects have the
         same legal rank and benefit under the Indenture as the Subsidiary
         Guarantees theretofore and thereafter issued in accordance with the
         terms of the Indenture as though all of such Subsidiary Guarantees had
         been issued at the date of the execution hereof.

                  (c) Except as set forth in Articles IV and V of the Indenture,
         and notwithstanding clauses (a) and (b) above, nothing contained in the
         Indenture or in any of the Notes shall prevent any consolidation or
         merger of a Guarantor with or into the Company or another Guarantor, or
         shall prevent any sale or conveyance of the property of a Guarantor as
         an entirety or substantially as an entirety to the Company or another
         Guarantor.

         5.       Releases.

                  (a) In the event of a sale or other disposition of all of the
         assets of any Guarantor, by way of merger, consolidation or otherwise,
         or a sale or other disposition of all of the capital stock of any
         Guarantor, then such Guarantor (in the event of a sale or other
         disposition, by way of merger, consolidation or otherwise, of all of
         the capital stock of such Guarantor) or the corporation acquiring the
         property (in the event of a sale or other disposition of all or
         substantially all of the assets of such Guarantor) will be released and
         relieved of any obligations under its Subsidiary Guarantee. The
         obligation to apply the Net Proceeds of such sale or other disposition
         in accordance with the applicable provisions of the Indenture,
         including without limitation Section 4.10 of the Indenture, shall
         continue to be enforceable. Upon delivery by the Company to the Trustee
         of an Officers' Certificate and an Opinion of Counsel to the effect
         that such sale or other disposition was made by the Company in
         accordance with the provisions of the Indenture, including without
         limitation Section 4.10 of the Indenture, the Trustee shall execute any
         documents reasonably required in order to evidence the release of any
         Guarantor from its obligations under its Subsidiary Guarantee.

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                  (b) Any Guarantor not released from its obligations under its
         Subsidiary Guarantee shall remain liable for the full amount of
         principal of and interest on the Notes and for the other obligations of
         any Guarantor under the Indenture as provided in Article X of the
         Indenture.

         6. No Recourse Against Others. No past, present or future director,
officer, employee, incorporator, stockholder or agent of the Guaranteeing
Subsidiary, as such, shall have any liability for any obligations of the Company
or any Guaranteeing Subsidiary under the Notes, any Subsidiary Guarantees, the
Indenture or this Supplemental Indenture or for any claim based on, in respect
of, or by reason of, such obligations or their creation. Each Holder of the
Notes by accepting a Note waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Notes. Such waiver may
not be effective to waive liabilities under the federal securities laws and it
is the view of the Commission that such a waiver is against public policy.

         7. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE BUT WITHOUT
GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT
THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

         8. Counterparts. The parties may sign any number of copies of this
Supplemental Indenture. Each signed copy shall be an original, but all of them
together represent the same agreement.

         9. Effect of Headings. The Section headings herein are for convenience
only and shall not affect the construction hereof.

         10. The Trustee. The Trustee shall not be responsible in any manner
whatsoever for or in respect of the validity or sufficiency of this Supplemental
Indenture or for or in respect of the recitals contained herein, all of which
recitals are made solely by the Guaranteeing Subsidiary and the Company.

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         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed and attested, all as of the date first above
written.

Dated:
                                 EMPIRE AIR SYSTEMS, INC., a New York 
                                 corporation



                                 By: Robert P. Robeson
                                    -----------------------------------         
                                     Robert P. Robeson
                                     Secretary/Treasurer

                                 U.S. BANK TRUST NATIONAL ASSOCIATION, 
                                 formerly known as FIRST TRUST NATIONAL 
                                 ASSOCIATION, as Trustee


                                 By: James D. Khami
                                    ------------------------------------
                                 Name: James D. Khami
                                 Title:  Vice President

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