Re: External inspection

Date:         29 Dec 98 03:12:30 
From:         Kees de LezenneCoulander <>
References:   1 2
Followups:    1
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Rob Montgomery <> wrote:

>Stephan Stephany LAC-CC wrote:
>>                     Preliminary investigation results showed that the
>>  aircraft's three static ports on the left side were obstructed by
>>  masking tape. The tape had been applied before washing and polishing >>
 of the aircraft prior to the accident flight."
>At the risk of sounding the fool, and admitting not to be an expert,
>wouldn't the prudent pilot abort the takeoff roll if airspeed
>indications were severly off the mark (i.e. at the cross-check)? I
>can't believe that any handling pilot would just eyeball the decision
>and rotation speeds.

     Certainly. But blocked static ports do not give any sign of an unusual
indication during the take-off roll. It is only when the aircraft gains
altitude that funny things start to happen (like strange altitude
indication, strange airspeed indication and strange rate of climb
indication all at the same time).
     Considering this happened in the middle of the night during a
departure out towards the sea, the crew did a pretty good job. They flew
the airplane for a considerable time and were on their way back to the
airport when they fell into the trap of believing the altitude the air
traffic controller gave them. Of course this was just the altitude as
reported by their transponder, which was also affected by the erroneous
static pressure.
                         Kees de Lezenne Coulander
  C.M. de Lezenne Coulander
  The Netherlands                    E-mail:

  Aircraft Development and Systems Engineering B.V.
  Schiphol-Rijk, The Netherlands