| for personal lights | 7 | purpose |
| always | 4 | degree |
| aircraft → be → required | 32 |
| aircraft → be → necessary | 11 |
| aircraft → be → need | 5 |
| aircraft → be → requirement | 4 |
| negative | neutral | positive |
| 0.177 | 0.732 | 0.091 |
| Raw frequency | 52 |
| Normalized frequency | 0.527 |
| Modifier score | 0.722 |
| Perplexity | 466.304 |