Ab-initio pilots' performance using T-VASIS versus PAPI - 2011

[PEREZGONZALEZ Jose D et al [eds] (2013). Ab-initio pilots' performance using T-VASIS versus PAPI. Knowledge (ISSN 2324-1624), 2013, pages 94-96.] [DOI] [Printer friendly]

T-VASIS versus PAPI

Lewis (20111) compared the accuracy with which a group of ab-initio pilots tracked the correct approach-to-landing glide path when using two different approach lighting systems (T-VASIS4 and PAPI5). Results (see illustration 1) show that pilots were better at tracking the correct glide slope in 8 scenarios out of 10 when using T-VASIS and in 2 scenarios out of 10 when using PAPI. On average, ab-initio pilots performed better with T-VASIS (mean difference = 6), a sensible difference of moderate magnitude (when attending to the unstandardized effect size).

Illustration 1. Average deviation from glide slope*
Scenario I II III IV V VI VII VIII IX X Mean StDev
PAPI 51 47 59 79 71 82 57 62 46 47 60 13
T-VASIS 43 46 61 63 59 72 47 52 53 45 54 9
Difference 8 1 -2 16 12 10 10 10 -7 2 6
Unstandardized effect size3 small 2 medium 6 large 9
(* Angular deviation from 0, multiplied by 100)

When questioned about their perception of fit-for-purpose and preference for one lighting system or the other, most pilots perceived T-VASIS as being a better visual system when flying on the glide slope or when above it, but perceived PAPI as being a better visual system when flying below the glide slope. Irrespective of perception, though, most preferred PAPI over T-VASIS.

Illustration 2. Assessment of best-fit-for-purpose and preference for approach lighting system
Number (%) of pilots who think best displays when Number (%) of pilots
On glide slope Above glide slope Below glide slope Who prefer
PAPI 6 (42%) 3 (21%) 8 (57%) 9 (55%)
T-VASIS 8 (57%) 11 (79%) 6 (43%) 5 (35%)

Editors

Jose D PEREZGONZALEZ (2013). Massey University, Turitea Campus, Private Bag 11-222, Palmerston North 4442, New Zealand. (JDPerezgonzalezJDPerezgonzalez).
dotwikifan (2012). (dotwikifandotwikifan).

Peer-reviewers

Steve GEDDES (2013). Massey University, New Zealand. (Steve GeddesSteve Geddes).
Sarah ROSS (2013). Massey University, New Zealand. (Sarah215Sarah215).
David ATKINSON (2013). Massey University, New Zealand. (DAtkinsonDAtkinson).

Want to know more?

LEWIS (2011) original article
The original article provides full detail about the research.
Skybrary - VASIS
This Skybrary page offers a small introduction to different visual approach slope indicators (such as T-VASIS and PAPI).

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License