Exhibit 10.4

ACKNOWLEDGEMENT OF CONTINUING GUARANTY AND CONSENT

Navtech, Inc., a Delaware corporation (“Parent”), is a party to a Parent
Guaranty dated as of November 22, 2005 (the “Parent Guaranty”) in favor of ABRY
Mezzanine Partners, L.P., individually and as agent, and the other undersigned
entities are parties (directly or by means of a joinder) to the Subsidiary
Guaranty dated as of November 22, 2005 (the “Subsidiary Guaranty” and, together
with the Parent Guaranty, the “Guaranties”, and each a “Guaranty”) in favor of
ABRY Mezzanine Partners, L.P., individually and as agent .

As of the date hereof, Parent and Navtech Systems Support, Inc., a company
incorporated under the laws of Ontario (the “Company”), have entered into a
Purchase Agreement and Second Amendment to Note Purchase Agreement (the “Second
Amendment”) pursuant to which the Company may issue one or more of the 2007
Tranche B Notes referred to therein (the “2007 Notes”).

Each of the undersigned hereby acknowledges, consents and agrees to the Second
Amendment.  Specifically and without limitation, each of the undersigned
entities acknowledges and agrees that the 2007 Notes constitute “Notes” under
the Note Purchase Agreement, that the Company’s obligations in respect of the
2007 Notes constitute “Guaranteed Obligations” under Guaranty to which such
undersigned entity is a party, and that the Guaranty to which such undersigned
entity is a party is and remains in full force and effect as of the date hereof.

[The remainder of this page is intentionally left blank].

--------------------------------------------------------------------------------

IN WITNESS WHEREOF, each of the undersigned has executed this Acknowledgement of
Continuing Guaranty and Consent as of this 28th day of August, 2007.

 

NAVTECH, INC.

 

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

 

 

 

 

NAVTECH (UK) LIMITED

 

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

 

 

 

 

NAVTECH, LLC

 

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

 

 

 

 

EUROPEAN AERONAUTICAL GROUP UK LIMITED

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

 

 

 

 

EUROPEAN AERONAUTICAL GROUP SWEDEN A.B.

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

 

 

 

 

NAVTECH A.B.

 

 

 

 

 

 

 

 

By:

 

 

 

Name:

 

 

 

Title:

 

 

 

--------------------------------------------------------------------------------