Tangled in the Details, Part 2
Author’s Note: This is the second of a three-part article that compares U.S., British and Pakistani safety board reports--followed by the conclusion in part three. As you read them, see if you can discern where I might be going with these articles. The reports are, for the most part, directly quoted, but I have inserted comments and cut portions for clarity and the purpose of proving my point.
Our second incident report concerns a British-registered Airbus A320 that was attempting a night landing in a sandstorm in the Sudan.
The commander was aware of the descent path shown on the chart and therefore expected to see the autopilot command a descent at KTM 5 DME, but instead the aircraft continued to fly level. (There were two different databases involved. One had been updated.) The commander stated that, at the time, he then mistakenly thought the flight control unit (FCU) was set to TRK/FPA. (This would be a mistake given the definition of a managed non-precision approach.) Approximately 4 nm from the threshold, the vertical speed/flight path angle knob on the FCU was pulled. This disengaged the managed final descent autopilot mode, in which the rate is controlled by the flight management and guidance system, and engaged the selected vertical speed mode, in which the rate is controlled by the VS/FPA.
The pilot stated that as the aircraft passed through KTM 5 DME, he set the autopilot to commence what he believed was a flight-path angle of 3.0 deg. down, whereas he later realized that he had commanded a descent at 300 fpm.
The aircraft began its descent and entered blowing sand with forward visibility reducing rapidly. The commander described the effect of the sand as like watching iron filings flying past the windscreen. The aircraft continued its descent. The copilot stated that the altitude check at 4 DME revealed the aircraft was about 200 ft. above the published descent profile. The commander stated that as the aircraft approached 3 DME it became apparent that it was not closing with the vertical profile, so he increased the rate of descent to about 2,000 fpm.
The aircraft then reached the minimum descent altitude (MDA). It has not been possible to establish exactly what was said between the pilots at this time. However, it is apparent that at some stage late in the approach the commander asked the copilot if he could see the approach lights. The copilot mistook this question to be the commander stating that he could see the lights. As a result, the copilot informed ATC that they could see the approach lights and requested confirmation that they were cleared to land. The commander, hearing the copilot’s transmission, took this to mean that the copilot had the approach lights in sight and looked up to see “running rabbit” strobe lights and some other lights in his one o’clock position. The confusion between the two pilots then became apparent and it was quickly realized that the lights seen just to the right of the aircraft were not the approach lights. This, combined with the disorientating effect of the aircraft’s landing lights reflecting off the blowing sand, caused the commander to order a go-around.
Our third report is from the Pakistan Aircraft Accident Investigation Board referencing the crash of Pakistani International Airlines (PIA) Flight 8303 on May 22, 2020. I should note that this is a preliminary report; therefore my comments must be considered to be for discussion purposes only as there have been no official causes enumerated to date.
The investigation so far into the available evidence--i.e., FDR/CVR readouts (preliminary assessment), footage from CCTV/security cameras at Jinnah International Airport (JIAP), and “Karachi Approach” radar data, etc.--has revealed and validated the preliminary findings: The reported weather at origin, en route and at destination airfields was fit to undertake the flight.
PIA Flight 8303, an Airbus A320, took off from Allama Iqbal International Airport (OPLA), Lahore at 1305 (as per the Lahore ATC recording/transcript). The departure from Lahore and cruising flight were uneventful. The crew did not follow standard callouts and did not observe CRM aspects during most parts of flight.
Area Control Karachi East cleared Flight 8303 for the Nawabshah 2A arrival procedure (STAR, Standard Terminal Arrival Route) and advised them to expect the ILS approach for Runway 25L at JIAP. The flight was later cleared at the pilot’s discretion to report direct to MAKLI (a waypoint 15 nm at a radial of 075 deg. from Karachi VOR) and descend to FL 100, and later re-cleared for FL 050. The aircraft changed over to Karachi Approach and was cleared to descend farther to 3,000 ft. by the time it reached MAKLI.
The Airbus ended up higher than the required descent profile. At MAKLI it was at 9,780 ft. and at about 245 KIAS. In order to manage the descent and lose the additional height, “OPEN DES” mode was selected via the FCU, both autopilots were disengaged and speed brakes were extended. Karachi Approach inquired “Confirm track mile comfortable for descend” and later advised the aircraft to take an orbit, so that it could be adjusted on the required descent profile. No orbit was executed and the effort to intercept the glideslope and localizer (of ILS) was continued. The FDR indicated lowering of the landing gear at 7,221 ft. approximately 10.5 nm from Runway 25L.
Karachi Approach advised repeatedly (twice to discontinue the approach and once cautioned) about excessive height. The landing approach was not discontinued. However, the FDR shows raising of the landing gear at 1,740 ft., followed by retraction of the speed brakes (at a distance slightly less than 5 nm from Runway 25L). At this time, the aircraft had intercepted the localizer as well as the glideslope. Flaps 1 was selected at 243 KIAS; the landing gear and speed brakes were retracted. Over-speed and EGPWS warnings were then triggered. Since the approach to land was continued, Karachi Approach, instead of changing over the aircraft to Aerodrome Control, sought telephonic landing clearance from Aerodrome Control. The tower conveyed a landing clearance of the aircraft (without observing the abnormality that the landing gear was not extended) to Karachi Approach. Subsequently Karachi Approach cleared the aircraft to land.
At 500 ft., the FDR indicates landing gear retracted, slat/flap configuration 3, airspeed of 220 KIAS and a descent rate of 2,000 fpm. According to the FDR and CVR recordings, several warnings and alerts, such as over-speed, landing gear not down and ground proximity alerts, were disregarded. The landing was undertaken with landing gear retracted. The aircraft touched the runway surface on its engines. The flight crew applied reverse engine power and initiated braking action. The engines scrubbed the runway at various locations, causing damage to both of them. Pictures show the engines touching the runway as well as sparks due to the scrubbing. Other shots show marks on the runway.
The tower observed the engines scrubbing on the runway but did not covey this abnormality to the aircraft. It was conveyed to Karachi Approach via telephone, however. Karachi Approach also did not relay this problem to the aircraft. The landing was discontinued and a go-around was executed. The FDR recording indicates a brief action of selection of the landing gear lever to the down position, which was immediately followed by its movement to the up position. The intention to undertake another ILS approach for landing on Runway 25L was conveyed; however, shortly after the go-around both engines failed. Ram air turbine (RAT) was deployed to power the essential systems.
The FDR stopped recording during this time frame (as per the design limitation). The aircraft was unable to maintain its required height. The flight crew declared the emergency situation that both engines were lost, and transmitted a mayday call. Evidence from the wreckage indicates reasons for the right engine failure; however, the left engine requires further examination, and the landing gear in the extended position did not demonstrate any malfunction of that system. The aircraft crashed about 4,396 ft. short of Runway 25L. It was a slow-speed impact with a high angle of attack, with the aircraft configuration indicating landing gear extended, slats at step/position 1, and flaps retracted. This configuration was ascertained and documented from the wreckage at the crash site (as the FDR data recording had stopped earlier). The aircraft was reportedly serviceable for this flight; necessary scrutiny of the maintenance records/documents is under way. The captain and first officer were adequately qualified and experienced to undertake the flight; scrutiny of the flight crew records/documents also is under way.