$re = '/^([A-Z]-[A-Z0-9]{4})_([A-Za-z0-9]+(?:_)?(?:[A-Za-z0-9]+)_[A-Za-z0-9]+(?:-[A-Za-z0-9]*)?)/';
$str = 'D-EBCB_Cessna_172-K
I-ZARY_Maule_MXT-7
I-ESML_Husky_A1
I-9865_P92_Echo_80CV
I-8982_P92_Echo_100CV
I-BLAE_PA28_Cadet
I-PIDR_PA28_Archer';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php