Two B738 and a B752 at Birmingham on Sep 8th 2020, landing with ladder on runway

Last Update: February 25, 2021 / 11:54:16 GMT/Zulu time

Bookmark this article

Photo of Ryanair EI-DPC, Boeing 737-800 — Ryanair EI-DPC, Boeing 737-800 (Photo credit: cvtperson / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Sep 8, 2020

Classification
Report

Airline
Ryanair

Flight number
FR-3902

Departure
Malta, Malta

Destination
Birmingham, United Kingdom

Aircraft Registration
EI-DPC

Aircraft Type
Boeing 737-800

ICAO Type Designator
B738

A Ryanair Boeing 737-800, registration EI-DPC performing flight FR-3902 from Malta (Malta) to Birmingham,EN (UK) with 35 passengers and 6 crew, landed on Birmingham's runway 33 at 23:25L (22:25Z) and vacated the runway.

A Jet2.com Boeing 737-800, registration G-GDFR performing flight LS-1244 from Chania (Greece) to Birmingham,EN (UK) with 181 passengers and 6 crew, landed on Birmingham's runway 33 at 23:27L (22:27Z), vacated the runway and reported they may have seen something on the runway in the touch down zone, they were not sure whether it was an object or something with the runway markings.

Following that report the crew of EI-DPC commented they may also have seen something just after the touch down markers.

A TUI Airways Boeing 757-200, registration G-OOBA performing flight BY-755 from Antalya (Turkey) to Birmingham,EN (UK) with 190 passengers and 8 crew, was on final approach to Birmingham's runway 33 when ATC queried whether they had heard the previous transmissions and whether they were happy to continue. The crew replied in the affirmative and continued the approach touching down at 23:29L (22:29Z). The aircraft vacated the runway, the crew reported they had seen a large object, possibly a ladder, on the runway in the touchdown zone just to the right of the center line.

Tower subsequently ordered a runway inspection which recovered a 7 ft A-frame step ladder from the runway.

On Feb 25th 2021 the UK AAIB released their bulletin concluding the probable causes of the serious incident were:

The ladder fell from WV4 during the drive along the runway, at the point where it accelerated in the touch down zone after the end of the supplementary lights. The means of securing the ladder in the rear of the open back vehicle using a bungee was not suitable. The bungee was available for use within the maintenance organisation’s facility, but its provenance was not known. More suitable securing equipment was available although not readily to hand.

The airport operator and the CAA have taken several safety actions to prevent reoccurrence.

The AAIB reported (times mentioned are in UTC/Z):

The last runway inspection was completed at 2128 hrs with nothing found on the runway.

The last aircraft movement before the three subsequent landings was a departure from Runway 15 at 2135 hrs.

The airport has surface movement radar (SMR) and all the airfield vehicles were fitted with transponders that identify the vehicle and its position on the SMR display in the ATC tower.

The SMR at Birmingham is not designed to detect foreign object debris (FOD).

...

WV4, the vehicle from which the ladder fell, was an all-wheel drive crew cab pickup truck with an open load bay and latched tail gate. The load bay was fitted with a rigid black plastic liner and there were two fixed cargo restraint rings attached towards the front and rear of the load side panels.

The vehicle was also fitted with two-way radio communication and external
work spotlights mounted on a roof rail on the left side.

...

When the technicians arrived for their shift there was a list of items for them to complete during the night if there was sufficient time available. This included some routine maintenance tasks on the Runway 33 approach lights and some of the centreline lights. They also needed to complete a check of all the runway lights in both directions. Technician 2 went out to complete a small job whilst Technician 1 remained at the engineering base. When Technician 2 returned, he rang ATC to ask when it might be possible to access the runway to perform the all lights check, work on the approach lights and the centreline lights task. He was informed that there would be a gap of around an hour beginning at 2130 hrs. The two technicians then began to prepare their equipment for the tasks and to load the WV4 which they had selected.

Technician 2 loaded the ladder, which would be required to access the approach lights, into the back of WV4. Having collected all their equipment, they set off for the runway with Technician 1 driving and Technician 2 in the front passenger seat. The routing from the engineering base to the runway required the vehicle to pass in front of the airfield fire station. The front of the fire station had a CCTV camera fitted (Figure 8). Although it was dark, the camera did capture the vehicle each time it passed. WV4 was seen passing the fire station at 2133 hrs.

At 2135 hrs WV4, having gained permission from ATC, entered Runway 33 from holding point S1. The vehicle then parked at the edge of the grass in the undershoot of the runway.

Once the vehicle was parked, Technician 2 got out of the vehicle, took the ladder from the back and proceeded down to the approach lights. Technician 1 remained in the vehicle. The maintenance work took approximately 15 minutes and upon returning to WV4, Technician 2 stated he secured the ladder in the back using the bungee, before returning to the passenger seat. WV4 then proceeded along the runway whilst the technicians checked the lights. This involved inspecting the centreline lights, edge lights and the supplementary lights in the touch down zone. This was the only time from when they left the engineering base at 2133 hrs to begin the work on the approach lights that they passed the point on the runway where the ladder was subsequently found; WV4 was calculated to be travelling at about 45 mph at the time when the ladder fell from the vehicle. The time was 2154 hrs.

Having driven to the end of Runway 33, WV4 was then turned around and headed for the first centreline light they were to attend to, which was number 104 (see Figure 3). The scheduled maintenance requirements for the centreline lights was to check the torque on the bolts holding the lights in position. To do this the technicians had a wireless Bluetoothequipped electronic torque wrench. This indicated to the technician doing the work when the correct torque was applied, and also transmitted the data to a mobile device which recorded the date and time of the work. When they reached centreline light 104, Technician 2 again got out the vehicle to complete the work. When he attempted to wirelessly connect the torque wrench with the mobile device, he found it would not do so and they therefore had to return to the engineering base in order to get it to work as required. WV4 vacated the runway at 2159 hrs. To drive to the engineering base, WV4 passed the front of the fire station and was captured on CCTV. Figure 11 is a CCTV image of WV4 with the tailgate of
the truck up, but the ladder not present.

When WV4 reached the engineering base, Technician 2 exited the vehicle and proceeded inside to get the torque wrench and mobile device to communicate. Technician 1 remained in the driver’s seat waiting for his colleague. At 2204 hrs they passed the front of the fire station en route to continue the maintenance on the runway centreline lights.

WV4 asked for and received ATC permission to enter Runway 33 from holding point T1. They proceeded to centreline light 104 and began to work their way towards the end of the runway from centreline light to centreline light. Again Technician 2 was completing the work whilst Technician 1 was driving the vehicle to the right of the centreline in support of his colleague. The vehicle exterior side spotlights were illuminating the work area for Technician 2.

At 2218 hrs Technician 1 was informed by ATC that the first inbound aircraft was 20 nm from touchdown. This was acknowledged by Technician 1, and Technician 2 got back into the vehicle before they vacated the runway via Taxiway B. The vehicle again passed the fire station at 2220 hrs as shown at Figure 12. Note, the tailgate of the truck is up, and the ladder is not present.

The technicians returned to the engineering base and went inside with the aim of establishing when there might be another gap in aircraft movements to enable them to complete their checks on the runway centreline lights. Having established that there would be a gap after the next landing aircraft, they proceeded back to WV4 ready to go out to the runway. As they approached the vehicle, they realised that the ladder was missing. This was at approximately 2230 hrs.

The technicians first thought was that the ladder had been borrowed and proceeded to drive to where they thought the person who might have the ladder was working. They found that the person was not working that night and, before they could do anything else, they received a call from the Airfield Duty Manager regarding the ladder that had been found on the runway. Neither technician could explain how the ladder had come out of WV4 and neither had seen or heard anything during their journey from the approach lights to centreline light 104.

When the second aircraft to land reported the presence of something in the touch down zone, ATC requested that an Airfield Safety Unit (ASU) vehicle be prepared to perform a runway inspection. This vehicle was cleared onto the runway immediately behind G-OOBA once it had touched down. The ASU vehicle located the ladder at 2231 hrs. The runway was immediately closed and remained so until after a full runway inspection had been carried out. The runway reopened at 2250 hrs.

The ladder had been on the runway for 37 minutes.

The AAIB analysed:

Choice and method of ladder restraint

At first sight the bungee may have seemed suitable to secure the ladder in WV4. However, when the actual method used was demonstrated, it could be seen why the bungee was unsuitable. The bungee had been stretched almost to its limits around a strut on the ladder and hooked to the right and left forward fixed rings in the load bay side panels (Figure 5). When the vehicle is stationary or moving slowly the method used would keep the ladder in place. Any gentle acceleration or moderate cornering would cause the ladder to move, and the remaining elasticity in the bungee would have provided sufficient restraint.

It is likely that as WV4 accelerated, having passed the aiming point markings, the ladder was caused to moved more rapidly, and its inertia resulted in a ‘snatch’ load on the bungee when it reached the limit of elasticity. At this point, the snatch load would have been transferred into the wire hooks fitted to the ends of the bungee. In this case one of the hooks opened out (Figure 7) making it less effective in the restraint ring. As a result it most likely unhooked, rapidly sprang back, and unravelled itself from the ladder strut. This left the now unrestrained ladder to topple rearwards from WV4. As it fell out and contacted the runway it slid a short distance before coming to a stop causing the abrasion to the edges of the plastic at the top of the ladder (Figure 6).

Given the grooved surface of the runway, the noise of the tyres, especially at speed, would have likely masked any sound made by the ladder as it left the truck. Both technicians were also concentrating on checking the runway lights ahead of the vehicle and therefore their attention would not have been focused on monitoring the ladder.

Radio communications

After the landing of the first aircraft (EI-DPC) no comment was made by the crew regarding anything they may have seen in the touch down zone. After the second aircraft (G-GDFR) taxied off the runway the crew commented that they thought they had seen something and described it as an object or paint. This prompted the crew of the first aircraft to comment that they may also have seen something although they did not give any detail about what they thought they had seen.

Given the comments of the first two aircraft it seems likely that both the controller and the crew of G-OOBA did not believe the item to be of significance. In fact, the overriding impression seemed to be that it was just paint or a marking on the runway.

As G-OOBA was within 4 nm of the threshold, Birmingham MATS Part 2 allowed the controller discretion to permit the aircraft to continue as long as the crew wished to do so. The wording given in the manual was deliberately open to prevent any confirmation bias within the operating crew. The crew of G-OOBA commented that the use of the phrase ‘are you happy to continue’ re-enforced the impression that there was nothing to be concerned about. This impression, together with the belief that it was probably paint, led to the decision of the crew to continue to land on Runway 33.

When faced with having to make a rapid decision about continuing the approach or going around the language used to convey information to the crew is vital. Had the crew of G-OOBA known there was a ladder on the runway they would have chosen to go around. Had the controller known of the ladder the controller would have instructed the crew of G-OOBA to perform a go-around. However, both the crew and the controller can only act on the information they have at the time.

Having been pre-warned to look for something in the touch down zone, the crew of G-OOBA spotted the object and were able to correctly identify it as a ladder. Given where the crew are concentrating their attention during touchdown and the speed of the aircraft at that point, it would have been difficult for the previous crews to identify the item as a foreign object.