Very hard landing of a Boeing 737-4Q8 in Exeter

Date & Time: Jan 19, 2021 at 0237 LT
Type of aircraft:
Operator:
Registration:
G-JMCY
Flight Type:
Survivors:
Yes
Schedule:
East Midlands – Exeter
MSN:
25114/2666
YOM:
1994
Flight number:
NPT05L
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
15218
Captain / Total hours on type:
9000.00
Circumstances:
The crew were scheduled to operate two cargo flights from Exeter Airport (EXT), Devon, to East Midlands Airport (EMA), Leicestershire, and return. The co-pilot was the PF for both sectors, and it was night. The sector from EXT to EMA was uneventful with the crew electing to landed with FLAP 40. The subsequent takeoff and climb from EMA to EXT proceeded without event. During the cruise the crew independently calculated the landing performance, using the aircraft manufacturer’s software, on their portable electronic devices. Runway 26 was forecast to be wet, so they planned to use FLAP 40 for the landing on Runway 26, with AUTOBRAKE 3. With both pilots being familiar with EXT the PF conducted a short brief of the pertinent points for the approach. However, while they did mention that the ILS had a 3.5° glideslope (GS), they did not mention that the stabilized approach criteria differed from that on a 3° GS. From the ATIS they noted that the weather seemed to be better than forecast and the surface wind was from 230° at 11 kt. The ATC provided the flight crew with radar vectors from ATC to the ILS on Runway 26 at EXT. The landing gear was lowered and FLAP 25 selected before the aircraft intercepted the GS. FLAP 40 (the landing flap) was selected on the GS just below 2,000 ft amsl. With a calculated VREF of 134 kt and a surface wind of 10 kt the PF planned to fly the approach with a VAPP of 140 kt. At about 10 nm finals, upon looking at the flight management computer, the PM noticed there was a 30 kt headwind, so a VAPP of 144 kt was selected on the Mode Control Panel (MCP). The crew became visual with the runway at about 1,000 ft aal. The PF then disconnected the Auto Pilot and Auto Throttle; the Flight Directors remained on. As the wind was now starting to decrease, the VAPP was then reduced from 142 to 140 kt at about 600 ft aal. As the wind reduced, towards the 10 kt surface wind, the PF made small adjustments to the power to maintain the IAS at or close to VAPP. At 500 ft radio altimeter (RA) the approach was declared stable by the crew, as per their standard operating procedures. At this point the aircraft had a pitch attitude of 2.5° nose down, the IAS was 143 kt, the rate of descent (ROD) was about 860 ft/min, the engines were operating at about 68% N1 and the aircraft was 0.4 dots above the GS. However, the ROD was increasing and soon thereafter was in excess of 1,150 ft/min. This was reduced to about 300 ft/min but soon increased again. At 320 ft RA, the aircraft went below the GS for about 8 seconds and, with a ROD of 1,700 ft/min, a “SINK RATE” GPWS alert was enunciated. The PF acknowledged this and corrected the flightpath to bring the aircraft back to the GS before stabilizing slightly above the GS; the PM called this deviation too. As the PF was correcting back to the GS the PM did not feel there was a need to take control. During this period the maximum recorded deviation was ¾ of a dot below the GS. At about 150 ft RA, with a ROD of 1,300 ft/min, there was a further “SINK RATE” GPWS alert, to which the PM said, “WATCH THAT SINK RATE”, followed by another “SINK RATE” alert, which the PF responded by saying “AND BACK…”. The commander recalled that as the aircraft crossed the threshold, at about 100 ft, the PF retarded the throttles, pitched the aircraft nose down, from about 5° nose up to 4° nose down, and then applied some power in the last few feet. During these final moments before the landing, there was another “SINK RATE” alert. The result was a hard landing. A “PULL UP” warning was also triggered by the GPWS, but it was not audible on the CVR. The last surface wind transmitted by ATC, just before the landing, was from 230° at 10 kt. During the rollout the commander took control, selected the thrust reversers and slowed down to taxi speed. After the aircraft had vacated the runway at Taxiway Bravo it became apparent the aircraft was listing to the left. During the After Landing checks the co-pilot tried to select FLAPS UP, but they would not move. There was then a HYDRAULIC LP caution. As there was still brake accumulator pressure the crew were content to taxi the aircraft slowly the short distance onto Stand 10. Once on stand the listing became more obvious. It was then that the crew realized there was something “seriously wrong” with the aircraft. After they had shut the aircraft down, the flight crew requested that the wheels were chocked, and the aircraft be connected to ground power before going outside to inspect the aircraft. Once outside a hydraulic leak was found and the airport RFFS, who were present to unload the aircraft, were informed.
Probable cause:
The aircraft suffered a hard landing as a result of the approach being continued after it became unstable after the aircraft had past the point where the crew had declared the approach stable and continued. Despite high rates of descent being observed beyond the stable point, together with associated alerts the crew elected to continue to land. Had the approach been discontinued and a GA flown, even at a low height, while the aircraft may have touched down the damage sustained may have been lessened. While the OM did not specifically state that an approach was to remain stable beyond the gate on the approach, the FCTM was specific that, if it did not remain stable, a GA should be initiated. The commander may have given the co-pilot the benefit of doubt and believed she had the ability to correct an approach that became unstable in the final few hundred feet of the approach. However, had there been any doubt, a GA should be executed.
Final Report:

Crash of a Boeing 737-476SF in East Midlands

Date & Time: Apr 29, 2014 at 0228 LT
Type of aircraft:
Operator:
Registration:
EI-STD
Flight Type:
Survivors:
Yes
Schedule:
Paris-Roissy-Charles de Gaulle – East Midlands
MSN:
24433/1881
YOM:
1990
Flight number:
ABR1748
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
4279
Captain / Total hours on type:
377.00
Copilot / Total flying hours:
3900
Circumstances:
The aircraft was scheduled to operate three commercial air transport (cargo) sectors: from Athens to Bergamo, then to Paris Charles de Gaulle, and finally East Midlands. The aircraft’s flap load relief system was inoperative, which meant that the maximum flap position to be used in flight was 30, rather than 40º. This defect had been deferred in the aircraft’s technical log and it had no effect on the landing of the aircraft. Otherwise, the aircraft was fully serviceable. The co-pilot completed the pre-flight external inspection of the aircraft in good light, and found nothing amiss. The departure from Athens was uneventful, but a combination of factors affecting Bergamo (including poor weather, absence of precision approach aids, and work in progress affecting the available landing distance) led the crew to decide to route directly to Paris, where a normal landing was carried out. The aircraft departed Paris for East Midlands at 0040 hrs, loaded with 10 tonnes of freight, 8 tonnes of fuel (the minimum required was 5.6 tonnes), and with the co-pilot as Pilot Flying. Once established in the cruise, the flight crew obtained the latest ATIS information from East Midlands, which stated that Runway 27 was in use, although there was a slight tailwind, and Low Visibility Procedures (LVPs) were in force. They planned to exchange control at about FL100 in the descent, for the commander to carry out a Category III autoland. However, as they neared their destination, the weather improved, LVPs were cancelled, and the flight crew re-briefed for an autopilot approach, followed by a manual landing, to be carried out by the co-pilot. The landing was to be with Flap 30, Autobrake 2, and idle reverse thrust. The final ATIS transmission which the flight crew noted before landing stated that the wind was 130/05 kt, visibility was 3,000 metres in mist, and the cloud was broken at 600 ft aal. The commander of EI-STD established radio contact with the tower controller, and the aircraft was cleared to land; the surface wind was transmitted as 090/05 kt. The touchdown was unremarkable, and the autobrake functioned normally, while the co-pilot applied idle reverse thrust on the engines. As the aircraft’s speed reduced through approximately 60 kt, the co-pilot handed control to the commander, who then made a brake pedal application to disengage the autobrake system. However, the system remained engaged, so he made a second, more positive, brake application. The aircraft “shuddered” and rolled slightly left-wing-low as the lower part of the left main landing gear detached. The commander used the steering tiller to try to keep the aircraft tracking straight along the runway centreline, but it came to a halt slightly off the centreline, resting on its right main landing gear, the remains of the left main landing gear leg, and the left engine lower cowl. The co-pilot saw some smoke drift past the aircraft as it came to a halt. The co-pilot made a transmission to the tower controller, reporting that the aircraft was in difficulties, after which the co-pilot of another aircraft (which was taxiing from its parking position along the parallel taxiway) made a transmission referring to smoke from the 737’s landing gear. The commander of EI-STD had reached the conclusion that one of the main landing gear legs had failed, but as a result of the other pilot’s transmission, he was also concerned that the aircraft might be on fire. The commander immediately moved both engine start levers to the cut-off positions, shutting down the engines. Three RFFS vehicles had by now arrived at the adjacent taxiway intersection, and their presence there prompted the commander to consider that the aircraft was not on fire (he believed that if it were, the vehicles would have adopted positions closer by and begun to apply fire-fighting media). The RFFS vehicles then moved closer to the aircraft and fire-fighters placed a ladder against door L1, which the co-pilot had opened. Having spoken to fire-fighters while standing in the entrance vestibule, the commander returned to the flight deck and switched off the battery. The flight crew were assisted from the aircraft and fire-fighters applied foam around the landing gear and engine to make the area safe. The commander had taken the Notoc2 with him from the aircraft, and informed fire-fighters of the dangerous goods on board the aircraft.
Probable cause:
The damage to the flap system, fuselage, and MLG equipment was attributable to the detachment of the left MLG axle, wheel and brake assembly. The damage to the MLG outer cylinder, engine and nacelle was as result of the aircraft settling and sliding along the runway. The left MLG axle assembly detached from the inner cylinder due to the momentary increase in bending load during the transition from auto to manual braking. The failure was as a result of stress corrosion cracking and fatigue weakening the high strength steel substrate at a point approximately 75 mm above the axle. It is likely that some degree of heat damage was sustained by the inner cylinder during the overhaul process, as indicated by the presence of chicken wire cracking within the chrome plating over the majority of its surface. However, this was not severe enough to have damaged the steel substrate and therefore may have been coincidental. Although the risk of heat damage occurring during complex landing gear plating and refinishing processes is well understood and therefore mitigated by the manufacturers and overhaul agencies, damage during the most recent refinishing process cannot be discounted. The origin of the failure was an area of intense, but very localized heating, which damaged the chrome protection and changed the metallurgy; ie the formation of martensite within the steel substrate. This resulted in a surface corrosion pit, which, along with the metallurgical change, led to stress corrosion cracking, fatigue propagation and the eventual failure of the inner cylinder under normal loading.
Final Report:

Crash of a Boeing 737-301F in East Midlands

Date & Time: Jun 15, 2006 at 0502 LT
Type of aircraft:
Operator:
Registration:
OO-TND
Flight Type:
Survivors:
Yes
Schedule:
Liège - Stansted
MSN:
23515/1355
YOM:
1987
Flight number:
TAY325N
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
8325
Captain / Total hours on type:
4100.00
Copilot / Total flying hours:
1674
Copilot / Total hours on type:
1377
Aircraft flight hours:
45832
Aircraft flight cycles:
34088
Circumstances:
On a scheduled cargo flight from Liège Airport to London Stansted Airport the crew diverted to Nottingham East Midlands Airport due to unexpectedly poor weather conditions at Stansted. The weather conditions at EMA required a CAT IIIA approach and landing. On approach, at approximately 500 feet agl, the crew were passed a message by ATC advising them of a company request to divert to Liverpool Airport. The commander inadvertently disconnected both autopilots whilst attempting to reply to ATC. He then attempted to re-engage the autopilot in order to continue the approach. The aircraft diverged to the left of the runway centreline and developed a high rate of descent. The commander commenced a go-around but was too late to prevent the aircraft contacting the grass some 90 m to the left of the runway centreline. The aircraft became airborne again but, during contact with the ground, the right main landing gear had broken off. The crew subsequently made an emergency landing at Birmingham Airport (BHX).
Probable cause:
Causal factors:
1. ATC inappropriately transmitted a company R/T message when the aircraft was at a late stage of a CAT III automatic approach.
2. The commander inadvertently disconnected the autopilots in attempting to respond to the R/T message.
3. The crew did not make a decision to go-around when it was required after the disconnection of both autopilots below 500 ft during a CAT III approach.
4. The commander lost situational awareness in the latter stages of the approach, following his inadvertent disconnection of the autopilots.
5. The co-pilot did not call ‘go-around’ until after the aircraft had contacted the ground.
Contributory factors:
1. The weather forecast gave no indication that mist and fog might occur.
2. The commander re-engaged one of the autopilots during a CAT III approach, following the inadvertent disconnection of both autopilots at 400 feet aal.
3. The training of the co-pilot was ineffective in respect of his understanding that he could call for a go-around during an approach.
Final Report: