Splicing an array from an array of arrays (a 2-D array) is no different than splicing an element from an array of scalars (a 1-D array). That's because an AoA is really just an array of array references, and references are stored as scalars. For example:

use strict;
use warnings;

use Data::Dumper;

my @aoa = ( [ qw( CR 161508 111847 151085 190251 ) ],
            [ qw( CR 161509 111847 190251 190252 ) ],
            [ qw( CR 161510 111847 190252 190150 ) ],
            [ qw( CR 161511 111847 190150 190153 ) ] );

print "orig aoa: @aoa\n";
print Dumper( \@aoa ), "\n";

my @spliced = splice( @aoa, 1, 1 );

print "spliced aoa: @aoa\n";
print Dumper( \@aoa ), "\n";

print "spliced: @spliced\n";
print Dumper( \@spliced ), "\n";
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The output from this code is as follows:

orig aoa: ARRAY(0x183f064) ARRAY(0x18350e8) ARRAY(0x1835190) ARRAY(0x1
+835238)
$VAR1 = [
          [
            'CR',
            '161508',
            '111847',
            '151085',
            '190251'
          ],
          [
            'CR',
            '161509',
            '111847',
            '190251',
            '190252'
          ],
          [
            'CR',
            '161510',
            '111847',
            '190252',
            '190150'
          ],
          [
            'CR',
            '161511',
            '111847',
            '190150',
            '190153'
          ]
        ];

spliced aoa: ARRAY(0x183f064) ARRAY(0x1835190) ARRAY(0x1835238)
$VAR1 = [
          [
            'CR',
            '161508',
            '111847',
            '151085',
            '190251'
          ],
          [
            'CR',
            '161510',
            '111847',
            '190252',
            '190150'
          ],
          [
            'CR',
            '161511',
            '111847',
            '190150',
            '190153'
          ]
        ];

spliced: ARRAY(0x18350e8)
$VAR1 = [
          [
            'CR',
            '161509',
            '111847',
            '190251',
            '190252'
          ]
        ];
[download]

HTH