| Disaggregation of Revenue | 
 The following table presents our revenue disaggregated by Market Segments as follows: 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
 | 
 | 
Nine Months Ended | 
 | 
Three Months Ended | 
 
| (In thousands) | 
 | 
September 26, 2020 | 
 | 
September 28, 2019 | 
 | 
September 26, 2020 | 
 | 
September 28, 2019 | 
 
| Aerospace Segment | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
Commercial Transport  | 
 | 
$ | 
214,390  | 
 | 
 | 
$ | 
393,721  | 
 | 
 | 
$ | 
44,067  | 
 | 
 | 
$ | 
122,212  | 
 | 
 
Military  | 
 | 
50,329  | 
 | 
 | 
57,753  | 
 | 
 | 
18,164  | 
 | 
 | 
17,255  | 
 | 
 
Business Jet  | 
 | 
45,259  | 
 | 
 | 
49,555  | 
 | 
 | 
14,711  | 
 | 
 | 
12,432  | 
 | 
 
Other  | 
 | 
16,213  | 
 | 
 | 
19,461  | 
 | 
 | 
5,606  | 
 | 
 | 
5,803  | 
 | 
 
| Aerospace Total | 
 | 
326,191  | 
 | 
 | 
520,490  | 
 | 
 | 
82,548  | 
 | 
 | 
157,702  | 
 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Test Systems Segment | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
Semiconductor  | 
 | 
3,407  | 
 | 
 | 
7,815  | 
 | 
 | 
585  | 
 | 
 | 
2,219  | 
 | 
 
Aerospace & Defense  | 
 | 
58,186  | 
 | 
 | 
45,985  | 
 | 
 | 
23,373  | 
 | 
 | 
17,097  | 
 | 
 
| Test Systems Total | 
 | 
61,593  | 
 | 
 | 
53,800  | 
 | 
 | 
23,958  | 
 | 
 | 
19,316  | 
 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Total | 
 | 
$ | 
387,784  | 
 | 
 | 
$ | 
574,290  | 
 | 
 | 
$ | 
106,506  | 
 | 
 | 
$ | 
177,018  | 
 | 
 
  
The following table presents our revenue disaggregated by Product Lines as follows: 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
 | 
 | 
Nine Months Ended | 
 | 
Three Months Ended | 
 
| (In thousands) | 
 | 
September 26, 2020 | 
 | 
September 28, 2019 | 
 | 
September 26, 2020 | 
 | 
September 28, 2019 | 
 
| Aerospace Segment | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
Electrical Power & Motion  | 
 | 
$ | 
148,500  | 
 | 
 | 
$ | 
255,007  | 
 | 
 | 
$ | 
32,481  | 
 | 
 | 
$ | 
78,428  | 
 | 
 
Lighting & Safety  | 
 | 
90,973  | 
 | 
 | 
139,502  | 
 | 
 | 
25,320  | 
 | 
 | 
44,127  | 
 | 
 
Avionics  | 
 | 
57,381  | 
 | 
 | 
79,414  | 
 | 
 | 
16,104  | 
 | 
 | 
19,871  | 
 | 
 
Systems Certification  | 
 | 
5,596  | 
 | 
 | 
9,050  | 
 | 
 | 
605  | 
 | 
 | 
3,384  | 
 | 
 
Structures  | 
 | 
7,528  | 
 | 
 | 
18,056  | 
 | 
 | 
2,432  | 
 | 
 | 
6,089  | 
 | 
 
Other  | 
 | 
16,213  | 
 | 
 | 
19,461  | 
 | 
 | 
5,606  | 
 | 
 | 
5,803  | 
 | 
 
| Aerospace Total | 
 | 
326,191  | 
 | 
 | 
520,490  | 
 | 
 | 
82,548  | 
 | 
 | 
157,702  | 
 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Test Systems | 
 | 
61,593  | 
 | 
 | 
53,800  | 
 | 
 | 
23,958  | 
 | 
 | 
19,316  | 
 | 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
| Total | 
 | 
$ | 
387,784  | 
 | 
 | 
$ | 
574,290  | 
 | 
 | 
$ | 
106,506  | 
 | 
 | 
$ | 
177,018  | 
 | 
 
  
 |