Crash of the Polish Air Force One, 2014 Status Report
By Maria Szonert Binienda, J.D.
SCNDMSB2014SR

II. Air Navigation

Landing Charts & Glide Path

Another significant contradiction presented in the Russian Report relates to the analysis of landing charts. A test flight was performed at the Severny Airport on March 15, 2010, with the glide path angle of 2°40'. This glide path angle was used on the approach cards that were made available to the pilots of the Polish Air Force One flight on April 10, 2010. After the crash, on April 15, 2010, the Russian side performed a second fly-around test at the Severny airfield with the glide path angle of 3°12.3’. This second glide path angle was then selected for further calculations by the IAC. In its comments, the Polish side points out that “there has been no analysis regarding the path of 2°40' (±30) valid for the approach cards. The explanation for changes in the path of 2°40' to 3°12.3' may be an attempt to explain the lack of response from KSL [Landing Zone Controller] to the deviation of the Polish Air Force One position from the valid glide path outside the permissible tolerance.”³¹

The lack of response of the Landing Zone Controller to the wrong position with respect to the glide path is further justified by the Russian Report as follows: “Thus, in the accident flight the landing zone controller saw the aircraft blip on the radar as being referenced to glide path of ~3°10’. The inaccuracy was about 0.5°, which is equal to the tolerance area range.”

The analyses of the glide path of 3°10' do not correspond with the valid and published path of 2°40'. Furthermore, the information presented by IAC indicates that “the aircraft blip was outside of the permissible error area of the linear deviation, even for the path of 3°10’, [the problem] which is not commented by the authors of the [Russian] Report.” However, calculations carried out by the Polish side that take into account the position of the aircraft in relation to the glide path of 3°10’ show that “at a distance of 3.3 km to the DS26 the permissible error of linear deviation is ± 28 m, i.e. with a tolerance of 1/3 of the value that is below - 9.33 m, KSL should have informed the crew of its wrong position on the path. The conclusion is that even before reaching 3 km, KSL continued to inform the crew of their correct position 'on the course and path', when in fact the flight of the aircraft was lowering, increasing its vertical distance from the path.” ³²

The Russian Report also includes the following statement: “At 10:39:10 the controller informed the crew that they were 10 km from the runway threshold and had reached the glide path entrance point.” According to the Polish side, “informing the crew that at a distance of 10 km the aircraft had reached the glide path entrance point [means] that the KSL guided the aircraft according to the approach glide path angle 2°40' that was in force on cards.”

In analyzing the last phase of the flight, the IAC decided to change the glide path angle from 2°40' to 3°12’. In fact, three different glide path angles 2°40', 3°10' and 3°12.3, are used throughout the Russian Report. According to the Polish Response, in the Russian Report “various angles of the descent path are referred to depending on the need for conducting the analysis, which gives the impression that the choice of path was dictated by the need to prove that on the radar screen the blip of the aircraft was always “on course.” In addition, there is a statement saying that in fact the flight crew performed the flight with an angle of 5°.” Therefore, the Polish side was forced to ask: what angle of the path should be used here if even the path of 5° did not cause distress and reaction of radar guidance controllers?“

According to the Polish side, when using the gliding angle of 2°40' the airplane was on gliding path only at a distance of 10 km from the landing beam and at a distance of 2.78 km while crossing the gliding path. At all other times in a distance from 9 km to 2.78 km from the landing beam, the margin of error was in the range from 200% to 600%. At a distance from 2.78 km to 1.48 km, the airplane was below the gliding path with the error ranging from 300 to 600%.

Even assuming the incorrectly applied gliding path angle of 3°10' used by the IAC, the airplane would have remained 75% of the time outside the gliding path. At a distance of 3 km from the airport beam, it was dangerously below the gliding path, exceeding the accepted margin of error by 10% and at 2.5 km to 1.95 km by 1000%. The Flight Control group reacted only at 1.45 km from the airport beam where the accepted error exceeded 1600%.

When the crew crossed 'level 101' the FCG did not alert the pilots about the problem but instead reassured the crew that they were on course and on the correct path, misleading the crew about the actual distance from the runway beam. The FCG did not correct this misleading information for at least 30 seconds.

Although the aircraft was for 29 seconds outside the zone – below the gliding path – Landing Zone Controller did not give the crew information about its incorrect position relative to the path, still incorrectly informing them of the correct position “on course and on path. ” The command “Level 101” (10:40:53.4) was given about 14 seconds after informing the crew that they were “two, on course, on the glide path.” (10:40:39.9) The command “Level 101” was issued by Landing Zone Controller too late, when the aircraft's marker had already disappeared from the indicator (according to the testimony).

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Footnotes:

³¹ Polish Response in English.

³² Ibid.