EXHIBIT 12.1

TRANSDIGM HOLDING COMPANY

COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

(Dollars in Thousands)

	Fiscal Year Ended September 30,									October 1, 2002 Through July 22, 2003			July 23, 2003 Through Sept. 30, 2003
	1999			2000		2001		2002
Earnings:
Total earnings (loss)	$	(16,917	)	$	10,779	$	14,358	$	30,629	$	(69,969	)	$	(2,788	)
Income tax provision (benefit)		(2,772	)		7,972		9,386		16,804		(40,701	)		(2,275	)
Pre Tax Earnings (loss)		(19,689	)		18,751		23,744		47,433		(110,670	)		(5,063	)
Fixed charges:
Interest charges		22,722			28,563		31,926		36,538		28,224			9,567
Interest factor of operating rents		227			323		365		419		408			163
Total fixed charges		22,949			28,886		32,291		36,957		28,632			9,730
Earnings as adjusted	$	3,260		$	47,637	$	56,035	$	84,390	$	(82,038	)	$	4,667
Ratio of earnings to fixed charges(1)		—			1.6		1.7		2.3		—			—

(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.