Slippery runway & more so the safety area at Kozhikode may be a leading cause of the Air India Express crash

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RESA  The entire state machinery is on overdrive to defend the Calicut Airport stating that it was completely safe for flight operations. There are two significant points to focus on while determining the causes of the accident.  1. Previous safety audits have pointed to vegetation on the runway end safety area (RESA). 2. The rubber deposits at the ends of the runway may have been a contributory cause of the accident. Comparison A comparison of the runway friction values indicates a possibility of higher rubber deposits or poor runway friction levels at both ends of the runways. A friction level below 0.47 requires maintenance action as per the Indian Aeronautical Information Publication. The combination of runway friction and vegetation on the RESA may have been a significant factor that may have caused the Air India Express 1344 runway overrun at Kozhikode on 7th Aug 2020. Must note that the runway has a pronounced crown close to the middle and drops more than 25 feet on either side.

Much defended, Kozhikode Runway RESA & Runway Strip do not meet ICAO standards

RESA
 

The Runway End Safety Area is mandated by ICAO in Annex 14 as a standard. Following is the definition:

An area symmetrical about the extended runway centre line and adjacent to the end of the
strip primarily intended to reduce the risk of damage to an aeroplane undershooting or overrunning the runway.


ICAO Annex 14 requirements



Kozhikode airport design of the RESA has used the width of the turn pad at both ends of the runway to meet the 90m, double the width of the runway requirement of ICAO Annex-14. Unfortunately, ICAO  Annex-14 as per definition specifically defines RESA with the terms Extended Centerline and Symmetrical.

This implies that RESA must extent 45m either side of the extended centerline all the way till 240m. The Kozhikode RESA does not meet the ICAO standard by 10 m.

Technically if 10 m is significant, Kozhikode is not a RESA as per ICAO standards. 

Recommendation.— The width of a runway end safety area should, wherever practicable, be equal to that of the graded portion of the associated runway strip.

 

 Runway Strip requirements ICAO Annex 14

ICAO Annex-14 Extract on width of the Runway Strip


Width:

Width of runway strips
3.4.3 A strip including a precision approach runway shall, wherever practicable, extend laterally to a distance of at
least:
140 m where the code number is 3 or 4

Legal meaning of Practicable means available and capable of being done after taking into consideration cost, existing technology, and logistics in light of overall project purposes.

Runway Excursion Risk Reduction ICAO Aerodrome Best Practice
 

Airport Authority of India has issued a tender in 2019 for grading of the area beyond the runway strip with 330 days set as the work period. This clearly indicates that a 140m runway strip as mandated by ICAO is practicable but was not implemented for reasons which need to be probed. The tender amount seems miniscule compared to the cost involved though.

Tender for grading work on the runway strip

Therefore the Kozhikode runway is compliant for 1&2 aircraft's only since the Runway strip is 75 m either of the centerline and the Annex 14 requirement is 70m.

The runway is non compliant for aircraft's like B-737, A-320 and bigger.

Consequences of non-compliance with ICAO Annex-14 Runway Strip width requirements

75m Runway Strip as in Kozhikode
 

 

SpiceJet incident at Kozhikode 4th Aug2017

A320 Aerodrome reference code




Practicable means available and capable of being done after taking into consideration cost, existing technology, and logistics in light of overall project purposes.
Practicable means available and capable of being done after taking into consideration cost, existing technology, and logistics in light of overall project purposes.
Practicable means available and capable of being done after taking into consideration cost, existing technology, and logistics in light of overall project purposes.

AAI AIP RESA, read here.




Comments

  1. They can reduce RW length by ten meters and add it to RESA. But that won't solve the problem of tailwind landing.

    ReplyDelete
    Replies
    1. RESA is a distraction, why is there a big debate about it. Focus on why SOP's don't work. If it is about RESA then technically, they are falling short of 10m width.

      Delete
  2. CCJ has RESA of 93*90 on one end and 92*90 on the other end which Is twice the Width of runway (45mts). 10 mts shortage ? It also looks symmetrical with 45 mts on either side of the centreline. Correct me if I am wrong.

    ReplyDelete

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