SecProbe.io

Mail Stop 4561
Via Fax (610) 646-0149
        A p r i l  1 0 ,  2 0 0 9
 John C. Long Chief Financial Officer Innovative Solutions and Support, Inc. 720 Pennsylvania Drive Exton, PA 19341
Re: Innovative Solutions and Support, Inc.
Form 10-K and Form 10-K/A fo r the Fiscal Year Ended
September 30, 2008  Filed December 11, 2008 and December 19, 2008
  Form 10-Q for the Fiscal Quarter Ended December 31, 2008
  Filed on February 6, 2009
File No. 000-31157

Dear Mr. Long:

We have reviewed your response letter dated March 27, 2009 in connection with
the above-referenced filings and have the fo llowing comments.  If indicated, we think
you should revise your document in response to these comments.  If you disagree, we
will consider your explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as deta iled as necessary in your expl anation.  In some of our
comments, we may ask you to provide us w ith supplemental information so we may
better understand your disclosure.  After re viewing this information, we may raise
additional comments.  Unless otherwise noted, where prior comments are referred to they
refer to our letter dated February 27, 2009.

Form 10-K and Form 10-K/A for Fi scal Year Ended September 30, 2008

General
1. We note from your response to prior comme nt 1 that the ''typographical errors"
did not result in a mathematical mist ake based on your consideration of the
definition of an error pursuant to SFAS  154. However, the typographical error of
using the wrong net loss figure resulted in an error in the pres entation of the cash
flow statement and caused the mathematical calculations of "net cash provided by
(used in) operating activities", "net decr ease in cash and cash equivalents", and

John C. Long
Innovative Solutions and Support, Inc.
April 10, 2009 Page 2
"cash and cash equivalents, end of year" to  be incorrect. As a result, it appears
that the typographical errors would meet  the definition of an  error and, assuming
these errors are cons idered material, the Company should have filed an Item 4.02
8-K and labeled the related cash flow info rmation as restated, In this regard,
please provide the Company's SAB 99 analysis in determining whether these errors were considered to be material.
 Item 5. Market for the Registrant’s Comm on Equity, Related St ockholder Matters and
Issuer Repurchase of Equity Securities
 Comparison of the Five Y ear Total Return, page 20

2. Your response to prior comment 4 states that you do not use a published industry or line-of-business index because you are not aware of any such index made of
companies that are comparable to you and that would be accessible to your security holders or is widely recognized and used.  However, we note that other
companies in the aerospace and aviation industry, under such SIC codes as 3721,
3728, 3812, and 3823, which appear to be comp arable to you have identified and
used such indices for comparison in th eir performance graphs; including the
SPADES Defense index, the Dow Jones US Aerospace Index, or the S&P Aerospace and Defense Index.  Please advise  as to why identification and use of
such industry or line-of-business indices  are not feasible or appropriate; or
alternatively why you are unable to construc t an index of peer issuer(s), which
need not be limited to direct competitors.
 Note 3. Summary of Significant Accounting Policies, Revenue Recognition, page 39

3. You state in your response to prior comment 6 that the Company has not
recognized any revenue under SOP 97-2 in the historical fina ncial statements.
However, from your response to prior co mment 4 of your letter dated March 2,
2007, it appears that revenue from some of your arrangements was recognized
pursuant to SOP 97-2. Please clarify this  discrepancy and te ll us whether you
subsequently concluded that the arrange ments discussed in your March 2, 2007
response letter should have been acc ounted for pursuant to SAB 104 from
inception.  Also, tell us the percentage of revenue recognized  pursuant to SOP 97-
2 for each period presented and if applying SAB 104 would have resulted in different revenue recognition. Additionall y, tell us when and if there was a
specific event that caused the Company to  change its determination that SAB 104
was the appropriate guidance for revenue recognition.
4. Additionally, explain in detail,  how  you determined whether or not the
subsequent evaluation of the Company’s products, which resulted in the change
from SOP 97-2 to SAB 104, should be c onsidered a correction of an error
pursuant to SFAS 154.

John C. Long
Innovative Solutions and Support, Inc.
April 10, 2009 Page 3  5. Please refer to prior comment 8. Tell us how you considered disclosing that your
customer contracts include provisions "requiring the payment of all revenue
earned and costs incurred through the date of contract termination" to make it clear that there is no risk with respect to  refundable fees associ ated with contract
termination rights.
6. Please refer to prior comment 9 and tell us in further detail the factors management considered to determine th at the Eclipse inventory would not be
used for other products in Q1'09.  Additionally, we note that the Company stopped recognizing revenue in August
 2008 “after you became aware of
Eclipse’s deteriorating fina ncial condition.”  Please tell us what information the
Company considered to determine that August 2008 was the a ppropriate month to
cease revenue recognition for Eclipse and te ll us exactly when this information
became known to you.  In this regard, considering you ceased recognizing revenue in August, it appears that mana gement may have known about Eclipse’s
problems prior to the meeting referred to  in your response. Also, tell us the
amount of accounts receivable due from Eclipse at June 30, 2008 and tell us
whether any of these receivables were out standing for more than the Company’s
normal payment term (45 days).

* * * * * * *

Please respond to these comments within  10 business days or tell us when you
will provide us with a response.  Please  submit all correspondence and supplemental
materials on EDGAR as required by Rule 101 of Regulation S-T.  If you amend your
filing(s), you may wish to provide us with marked copies of any amendment to expedite our review.  Please furnish a cover letter that keys your response to our comments and provides any requested information.  Detailed co ver letters greatly faci litate our review.
Please understand that we may have addi tional comments after reviewing any
amendment and your response to our comments.
 You may contact Melissa Fe ider, Staff Accountant, at  (202) 551-3379 or me at
(202) 551-3499 if you have any questions regarding comments on the financial statements and related matters.  Please addre ss questions regarding all other comments to
Kevin Dougherty, Staff Attorne y, at (202) 551-3271 or Mark P. Shuman, Legal Branch
Chief, at (202) 551-3457.
       S i n c e r e l y ,           Kathleen Collins
Accounting Branch Chief