Letters From Our Readers April 2011

Reinvestigate the Tu-154 Crash?

I am grateful that you found the crash of a Polish [Tupolev] Tu-154 worth an article (‘Clash of Motives’, February 2011). It is vital in light of demands expressed by some local politicians for a new investigation.

What looks to be a textbook example of a classic controlled flight into terrain, where violation of procedures led to the accident, is now gaining an increased number of supporters of a ridiculous assassination plot theory.

The political and historical background links the crash to the atrocities suffered by the Polish people at the hands of the Russians. Those circumstances cause the final report published by the Russian Interstate Aviation Committee to be considered false and rejected.

To stop the turmoil, sooner or later some independent international body will have to get involved to verify the findings. This is the only way all factors leading to the accident can be identified and accepted, and preventive actions made obligatory to make sure that such an accident will not happen again.

Martin Dzieciuchowicz

Doing Not Quite the Right Thing?

The photo of the two mechanics with the article “Do the Right Thing” (February 2011) may not be illustrating what the article recommends.

The mechanic on the engine has no fall protection or fall restraint. The U.S. Occupational Health and Safety Administration (OSHA) requires general industry to have fall protection or fall restraint for work above 4 feet [1.2 meters]. And the individual below does not have eye protection on, but the one above on the engine does. So what is the policy in this workplace and who is looking out for whom? Compliance or noncompliance … or a little of both?

John Baxt
Director of Safety, Koch Aviation

TERPS Changes

I have read with interest the article “Dangerous Approaches” (ASW, 2/11, p. 38). I believe your effort to promote more knowledge of approach design criteria is very important.

I would like to bring to your attention that the U.S. Federal Aviation Administration TERPS [U.S. Standard for Terminal Instrument Procedures] has changed over the years and to highlight especially change 21, effective from June 5, 2009. One part of the revision was the radius to draw the circling area. Table 1 in the article (p. 42) refers to the old version of TERPS, which defines a smaller radius, a constant per given aircraft category.

Change 21 of TERPS introduces a radius that is a function not only of the fixed parameters of indicated airspeed, bank angle and straight segment, but also introduces the true airspeed, dependent on airport elevation and the height above the airport.
The radius calculated by the formula of change 21 will be larger than the fixed one provided in change 18, but still smaller than the one calculated by International Civil Aviation Organization PANS-OPS [Procedures for Air Navigation Services — Aircraft Operations] due to the different bank angle assumptions and the use of higher visual maneuvering indicated airspeeds for the calculation.

It may not be clear whether published procedures have been revised to reflect the latest changes to TERPS.

Tzvetomir Blajev
Eurocontrol