Overhead obstructions in modern airliners

Date:         10 Sep 97 19:38:46 
From:         Cass Alexander <cassa@ausnet.net.au>
Organization: ATC Systems Consultant
Followups:    1
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On 28 Aug 97 22:33:34 , Bob Mann <rwmannco@interport.net> wrote:

>As far as the elevation of the window belt-line goes, it's based on
>structural considerations and sited around 50th percentile passenger
>ergonomics -- well below 6' "average" heights.

Although Bob's reference was in relation to airliner windows, his
mention of the 50th percentile basis for ergonomic determination raises
the question of overhead obstructions in some modern airliners,
specifically those television monitors which are angled down several
inches (many centimetres) below the nominal over-aisle roof line.

I am 185 cm (6'2") tall and have occasionally bumped my head on the
lower edge of one of these monitors during normal de-planing. I have
also noticed tall cabin attendants having to "duck" the monitors during
their normal in-flight duties.

I have always been concerned that during an evacuation (when the cabin
may be dark and/or smoke filled) the monitors may present a safety
hazard to passengers and - most particularly - tall cabin crew members.

It seems that the 50th percentile may also have come into play in the
approval process for these monitors; as a result, they remain a source
of concern to me.

Any thoughts on this ?

And does anyone have indication of the crash-worthiness of the monitors;
are they likely to remain intact and in situ following a heavy landing ?

--
Cass Alexander
(The views expressed herein are my own; they are not necessarily)
(those of any organisation for which I may presently be working.)