Boeing's written analysis of the GS/PAPI deviation -
Document 2 Materials Laboratory 15 - Factual Report 13-062 (with 6 embedded images) Filing Date August 27, 2013 5 page(s) of Image (PDF or TIFF) 0 Photos
Based on the glideslope intercept guidance, at 250 feet geometric altitude (3800 feet
prior to the runway threshold), the airplane was slightly below the glideslope beam
(Figure 5). As the descent continued, the airplane passed through the beam at 145
feet geometric altitude (1650 feet prior to the runway threshold) and began to deviate
above the beam. The airplane continued to deviate above the beam and passed
through the 1-dot high profile at approximately 125 feet geometric altitude (1050 feet
prior to the runway threshold), and passed through the 2-dot high profile at 115 feet
geometric altitude (650 feet prior to the runway threshold). Based on the PAPI
intercept guidance, at 250 feet geometric altitude (3700 feet prior to the runway
threshold), the pilot’s eye was below the approach path. As the descent continued, the
pilot’s eye passed through the approach path at 130 feet geometric altitude (1000 feet
prior to the runway threshold) and began to deviate above the nominal approach
path. The airplane continued to deviate above the approach path, and the crew would
have received the slightly high (3 white/1 red) visual PAPI cue at 120 feet
geometric altitude (650 feet prior to the runway threshold) and would have
received the high (4 white/0 red) visual PAPI cue at 105 feet geometric altitude
(200 feet prior to the runway threshold). At the runway threshold, both the glideslope
deviation and PAPI visual guidance indicated that the airplane was high. The airplane
was following a 2.1-degree glide path from approximately 1400 feet prior to the
runway threshold to touchdown and was high on the approach. Touchdown occurred
at 1425 feet beyond the runway threshold on the runway centerline