Royal Maroc AT72 at Al Hoceima on Jul 9th 2018, hard landing in water short of runway

Last Update: July 13, 2020 / 07:36:02 GMT/Zulu time

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Incident Facts

Date of incident
Jul 9, 2018

Classification
Accident

Flight number
AT-439

Aircraft Registration
CN-COH

Aircraft Type
ATR ATR-72-200

ICAO Type Designator
AT72

A Royal Maroc Avions de Transport Regional ATR-72-212A, registration CN-COH performing flight AT-439 from Tangier to Al Hoceima (Morocco) with 54 passengers and 4 crew, was on final approach to AL Hoceima's runway 17 at about 20:04L (19:04Z) when the crew decided to go around due to missing visual cues. During the rotation for go around the aircraft touched down hard on the water about 2630 meters ahead of the runway. The aircraft climbed to FL090 and diverted to Nador (Morocco) for a safe landing. There were no injuries, the aircraft received substantial damage.

Morocco's AIB reported there were no injuries, the damage to the aircraft is being assessed. The occurrence was rated a serious incident (damage unknown) and is being investigated.

The occurrence aircraft had been involved in another hard landing earlier the year, see Incident: Royal Maroc AT72 at Al Hoceima on Apr 25th 2018, hard touchdown during go around.

The occurrence aircraft remained on the ground in Nador for about 10 weeks.

On Jul 12th 2020 Morocco's BEA released their final report in French only (Editorial note: to serve the purpose of global prevention of the repeat of causes leading to an occurrence an additional timely release of all occurrence reports in the only world spanning aviation language English would be necessary, a French only release does not achieve this purpose as set by ICAO annex 13 and just forces many aviators to waste much more time and effort each in trying to understand the circumstances leading to the occurrence. Aviators operating internationally are required to read/speak English besides their local language, investigators need to be able to read/write/speak English to communicate with their counterparts all around the globe).

The report concludes the probable causes of the accident were:

- non compliance with operational procedures, in particular the shut down of the GPWS and the continuation of an unsable approach below the stabilization level and the descent below minimum descent altitude without visual reference.

- due to the undue shutdown of the GPWS resulting in the absence of advisory call announcements during the approach the crew deprived themselves of any opportunity to become aware of and manage the situation developed by the "controlled flight towards terrain", the aircraft was in until touch down.

- Item 038-42-02-01 of the Dispatch Deviation Manual did not provide operation instruction O for the total failure of the GPWS, although the instructions would likely have caused the crew to not shut the GPWS down.

- deficiencies in the cockpit resource management amongst the flight crew, in particular communication, coordination and balancing the captain's authority gradient and the first officer's assertiveness, caused the first officer to act with delay against the instructions by the captain, which were incompatible with the stabilization criteria and the minimas of the approach.

The fact remains that the first officer's actions though delayed made it possible to limit the outcome to damage to the aircraft only.

The aircraft and crew had been dispatched for four sectors Casablanca-Al Hoceima-Tangier-Al Hoceima-Casablanca. The captain (61, ATPL, 13,487 hours total, 193 hours on type) was pilot flying on the first sector, the remaining three sectors were assigned to the first officer (25, CPL, 1063 hours total, 815 hours on type) as pilot flying.

Enroute at FL160 during the first sector the crew received a "TERRAIN" warning message on the EWD1 and an amber "TERRAIN FAULT" warning light. The warning indications disappeared after 6:38 minutes (and were probably caused by degradation of the GPS signal). The crew performed an RNAV approach to Al Hoceima's runway 17 in ceilings of 800 feet. Descending through the MDA (1030 feet MSL) the captain did not acquire the needed visual references but decided to continue the descent at 1000 fpm. About a minute later the TAWS activates "TERRAIN HEAD PULL UP!" and "AVOID TERRAIN" - the aircraft was at 60 feet MSL and 1760 meters ahead of the runway threshold at that time. The captain trims nose up and applies power to climb back to 108 feet MSL, minimum altitude was 45 feet MSL, and maintains 108 feet MSL until the runway came in sight, then completed the landing.

The aircraft subsequently continued to Tangier. Before departure from Tangier to Al Hoceima, due to the short duration of the flight, the crew briefed the approach to Al Hoceima. This time the crew would perform a VOR/DME approach to Al Hoceima's runway 17 (MDA 760 feet MSL). The captain explains that if the runway is not in sight at MDA they would descend to 400 feet MSL and maintain this altitude until the runway is in sight or the VOR/DME shows 2nm with the runway not in sight, then they would go around. After consultation with the dispatch deviation manual the captain agrees with the first officer's suggestion to shut the GPWS down to avoid alarms during approach and landing - the alarms encountered on the first sector were deemed invalid.

The aircraft performed a VOR/DME approach to runway 17. Descending through 4500 feet MSL the captain shut the GPWS down and reminded the first officer that at 2nm they needed to be at 700 feet, gear and flaps were needed for higher rate of descent. Desending to 2100 feet MSL on autopilot the first officer selects the speed to 170 KIAS. The latest weather information "Winds calm, visibility 4000 meters, mist, overcast at 006, temperature 23, dew point 23, QNH 1016" was acknowledged by the captain "we continue the approach". Descending through 2260 feet the altitude capture activates at which point the captain selected the altitude to 400 feet, the aircraft is 6.4nm from the runway threshold at 188 KIAS reducing. The crew selected vertical speed mode at -1200 fpm. At 1800 feet MSL the flaps are extended to 15 degrees, the speed is selected to 140 KIAS. The captain reports they were fully established and received the landing clearance. The landing gear is extended. The captain instructs "go to the limit", the vertical speed is increased to -1800 fpm, the aircraft descends through 1260 feet MSL at 155 KIAS.

The flaps were extended to 30 degrees 3.3nm before the runway threshold, the selected speed set to 119 KIAS and at the same time the altitude capture activates. The selected speed is further decreased to 106 KIAS, the aircraft levels off at 400 feet MSL, the captain announces "we continue" (assessing they were able to see 1000 feet and had the ground visual at 500 feet). At 2nm before the runway threshold vertical speed is set to -1800 fpm, the aircraft descends through 310 feet at 121 KIAS, the vertical rate is reduced to 1400 fpm when the aircraft descended through 135 feet radio altitude at 128 KIAS.

The first officer commented in his mother tongue "it's not normal" and subsequently "I'll take it manual". The autopilot is disengaged at 80 feet AGL and 130 KIAS, the first officer applies nose up inputs however the captain applies nose down inputs, the force differential between the inputs reach 68 daN three times. 2 seconds after descending through 80 feet AGL the first officer advances the thrust levers to 74 degree position, another 2 seconds later the landing gear indicates compressed.

The aircraft struck the water surface twice due to the captain's nose down inputs stronger than the first officer's nose up inputs. On second water contact the aircraft was 3 degrees nose down and experienced +3.92G vertical acceleration and 0.42G deceleration. The captain still applies a force of 40daN nose down while the first officer applies 28daN nose up, the captain's inputs reduces and the first officer's inputs increase and the aircraft climbs. A takeoff configuration warning "PWR MGT" activates for a second, the thrust levers are reduced to 64 degrees, and the pitch reaches 17 degrees nose up. The flaps are retracted, the aircraft climbs through 250 feet AGL about 1.03nm before the runway threshold climbing at 1900 fpm, the speed decays to a minimum of 103 KIAS. The landing gear is being retracted, the captain indicates the go around and requested the diversion to Nador, the aircraft climbs through 500 feet at 118 KIAS increasing about 0.61nm before the runway threshold. The aircraft continued for a landing in Nador without further incident.

The aircraft sustained damage to the aft belly and structural damage to stringers (deformations). In addition there was evidence the left and right hand RAM air intakes had been penetrated by seawater. Due to exceeding the structural limits the gear struts had to be replaced.

The BEA analysed the captain had only recently qualified for the ATR-72 after a long career as Boeing 737NG captain and instructor, the first officer was at the beginning of his career. The crew had agreed the captain would fly the first sector to demonstrate how to fly the approach into Al Hoceima, the remaining three sectors would be flown by the first officer.

Following the warnings enroute the TAWS activated during the approach with "TERRAIN AHEAD PULL UP" and "AVOID TERRAIN" warnings, the captain only reacts by climbing the aircraft to 108 feet AGL and continue the approach. Both crew reported that first improvised and unstable approach was not debriefed.

The second approach to Al Hoceima was unstabilized too with the airspeed significantly above stabilized speed passing the final approach fix at 75 knots above required speed. The aircraft descended through 1000 feet AGL at an appropriate speed but excessive rate of descent.

The Dispatch Deviation Manual permits for the GPWS to be inoperational but does not mandate operational procedures. However, later in the same chapter with respect to the advisory calls the manual stipulates that operational procedures are to be applied requiring announcements by the crew depending on the situation, configuration and mode. These announcements are necessary to compensate for the system failure and establish awareness of the situation between both pilot monitoring and pilot flying. The procdure would likely have stopped the crew decision to shut the GPWS down during the approach briefing prior to departure from Tangier.

The VOR/DME runway 17 procedure required weather minima of 3200 meters horizontal visibility and MDA of 760 feet, the prevailing weather conditions were 4000 meters horizontal visibitly and overcast cloud ceiling at 600 feet.
Incident Facts

Date of incident
Jul 9, 2018

Classification
Accident

Flight number
AT-439

Aircraft Registration
CN-COH

Aircraft Type
ATR ATR-72-200

ICAO Type Designator
AT72

This article is published under license from Avherald.com. © of text by Avherald.com.
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