Airblue Flight 202 Accident Report

Airplane Airbus A321-231, registration AP-BJB, serial number 1218, manufactured in 2000.

ACCIDENT

On 28 July 2010 the flight 202 took off from Karachi OPKC at 0150 UTC (0750 local time) destined to Islamabad OPRN.

The ATC lost contact with the aircraft at 0343 UTC (0943 local time). Information from ATC stated that 13 minutes earlier (I assume 0330 UTC) the airport was informed below minimums and therefore the landing was delayed.

METAR OPRN 0300 05016 2000 RA FEW 015 FEW TCU 030 SCT 040 BKN 100 24/23 1006.5 HPa

Which means Aviation Routine Observation Message from 0300 UTC (0900 local time) stating: Wind  050º at 16 Knots, Visibility 2,000 Meters, Rain, few clouds (1 to 2 octas) at 1,500 Feet, few Towering Cumulus clouds at 3,000 Feet, scattered clouds (2 to 5 octas), Broken clouds (6 to 8 octas) at 10,000 Feet, Temperature 24º C, Dew Point 23º C, Altimeter setting (QNH) 1006.5 HPa.

According to the ILSDME IAL for runway 30, the minima for initiating a CIRCLING APPROACH to runway 12 (runway in use at the moment) for Category C airplanes (case of the A321) is Ceiling 2,510 Feet and Visibility of 4,000 Meters (see the red dots and red underline in the provided figure 1).

The METAR clearly stated visibility of 2,000 Meters which is 2,000 Meters less than the minimum for initiating a CIRCLING APPROACH for runway 12.

One may also observe that the East/North and West sectors within the 10 Nm circle of the chart of the airport have numerous obstacles (hills) ranging from  2,115 Feet (lowest) to 3,100 Feet (highest). It’s also noticeable that there is a Prohibited Area (Presidential Palace) just beneath the “would be” flight path for a CIRCLING APPROACH. That area over flight must be avoided flying to the north (more close to the highest grounds).

The flight got into a CFIT  (Controlled Flight Into Terrain) whilst performing the CIRCLING APPROACH procedure to runway 12.

Observing  the Figure 2 one may notice that the airplane flew much more than needed to perform the CIRCLING APPROACH maneuver and hit high ground on a CFIT.

Did the Captain deliberately flew a longer distance in order to avoid the Prohibited Area (Presidential Palace)?

That’s the first question.

Another interesting speculation would be the notoriously difficulty handling characteristics of the Airbus airplanes when manually flying or when a pilot tries an abrupt maneuver in order to maintain terrain clearance, for instance.

Usually the Auto Pilot logic from those airplanes do not allow full pilot intervention even to avoid a potentially dangerous situation.

Airbus  aircraft past events have already proven in several occasions that pilots were prevented by the Auto Pilot logic to intervene when the need arose.

Figure 1

Figure 2

Go Around Procedure after an aborted Circling Approach:

Initiate a go around procedure any time during the CIRCLING APPROACH if or when of the following occurs:

1. Vertical visibility lost
2. Runway reference is lost
3. Any airplane abnormal condition that requires both pilots to deviate from the intended flight profile.
4. Non stabilized approach after initiating the final approach phase of the CIRCLING APPROACH.

Procedure:

Initiate a normal go around procedure banking the airplane towards the runway and intercept the standard Go Around Procedure published by the IAL (see figure 1).

  

Airblue 202 possible factors

- Rush to arrive as the flight was already 13 minutes late thanks to the weather.

- Low Ceiling

- Poor visibility (below the minimums for CIRCLING APPROACH according to the latest METAR)

- Lost track of the runway during CIRCLING APPROACH maneuver followed by improper Go Around procedure

- Overflight restrictions for the CIRCLING APPROACH maneuver due to the existence of  the Prohibited Area (Presidential Palace), therefore, requiring an extended flight right into the higher ground terrain.

- SOP factors

- Emergency during the Circling Approach

- Spatial Disorientation

- Aircraft Handling Issues after a Ground Proximity Warning Signal (if triggered). AIRBUS’ Auto Pilot known logic idiosyncrasies.

- The wind 050/16 had only a 4 Kt tail component for a direct landing on RWY 12 (unless that was not the actual wind condition during the flight final approach on the ILS). 
Why not proceed to a direct approach (SOPs rule or ATC instruction)?

A CIRCLING APPROACH maneuver provides an excellent opportunity to make a fatal mistake with respect to the stall margin. With flaps and gear extended, lots of additional power is required when leveling off to maintain airspeed.

Distractions outside the cockpit can easily divert the pilot's attention, compromising airspeed control and eroding the margin above stall speed.

Handling difficulties on the airplane such as trying to overcome an AUTO PILOT idiosyncrasy would be a major concern.

Loss of visual clues or the runway environment chiefly in a hilly and rugged terrain are also factors that need to be considered.

References

- Wikipedia: http://en.wikipedia.org/
- IFR Refresher article, 1997
- Robert Rossier; ATurn for the Worse, November 2003

- © Antonio Carlos Arantes De Biasi