EXHIBIT 12.1



TRANSDIGM HOLDING COMPANY

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(Dollars in Thousands)



|                                      |  | Fiscal Year Ended September 30, |         | October 1,2002ThroughJuly 22,2003 |      |   | July 23,2003ThroughSept. 30,2003 | 
|------------------------------------- |  | ------------------------------- | ------- | --------------------------------- | ---- | - | -------------------------------- | 
|                                      |  | 1999                            |         |                                   | 2000 |   | 2001                             | 
|Earnings:                             |  |                                 |         |                                   |      |   |                                  | 
|                                      |  |                                 |         |                                   |      |  
|Total earnings (loss)                 |  | $                               | (16,917 | )                                 |      | $ | 10,779                           | 
|Income tax provision (benefit)        |  |                                 | (2,772  | )                                 |      |   | 7,972                            | 
|                                      |  |                                 |         |                                   |      |   |                                  | 
|Pre Tax Earnings (loss)               |  |                                 | (19,689 | )                                 |      |   | 18,751                           | 
|                                      |  |                                 |         |                                   |      |   |                                  | 
|Fixed charges:                        |  |                                 |         |                                   |      |   |                                  | 
|                                      |  |                                 |         |                                   |      |  
|Interest charges                      |  |                                 | 22,722  |                                   |      |   | 28,563                           | 
|Interest factor of operating rents    |  |                                 | 227     |                                   |      |   | 323                              | 
|                                      |  |                                 |         |                                   |      |   |                                  | 
|Total fixed charges                   |  |                                 | 22,949  |                                   |      |   | 28,886                           | 
|                                      |  |                                 |         |                                   |      |   |                                  | 
|Earnings as adjusted                  |  | $                               | 3,260   |                                   |      | $ | 47,637                           | 
|                                      |  |                                 |         |                                   |      |   |                                  | 
|Ratio of earnings to fixed charges(1) |  |                                 |        |                                   |      |   | 1.6                              | 
|                                      |  |                                 |         |                                   |      |   |                                  | 

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|(1) | For purposes of computing the ratio of earnings to fixed charges, earnings consist of earnings before income taxes plus fixed charges. Fixed charges consist of interest expense,
amortization of debt issuance costs and the portion (approximately 33%) of rental expense that management believes is representative of the interest component of rental expense. Earnings were insufficient by $19,689, $110,670 and $5,063 to cover
fixed charges for the fiscal year ended September 30, 1999, the period October 1, 2002 through July 22, 2003, and the period July 23, 2003 through September 30, 2003, respectively.
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