Bird strikes: How airport is balancing conservation and aircraft protection

Mid-afternoon Friday finds us aboard one of the yellow and black bird scare vehicles, standing slightly off Runway 1735 at Entebbe International Airport (EIA). Dan Muhairwe, a wildlife hazard management officer with the Bird Hazard and Wildlife Control Unit of the Uganda Civil Aviation Authority (UCAA), is incharge of the vehicle. The car’s windshield is rein- forced with black metal mesh.

A pyrotechnic singleshot pistol lies in the footwell of the passenger seat, while a laser bird repel- lent beam shot lies near the gear. Lights are blinking on the centre console of the car. Slowly, Muhairwe rolls the car down a small road that connects to the runway. At the barrier sign, he stops and radios Air Traffic Control requesting for permission to access Runway 1735. In under a minute, permission is granted and we drive on to Entebbe International Airport’s major runway. The bird scare vehicle is going to perform a runway sweep just a few minutes before a Uganda Airlines flight jets in.

“We carry out sweeps for birds and wildlife for all departures and arrivals to make sure the runway is safe for the aircraft to use,” Muhairwe says as he parks the vehicle at a spot where there are four egrets are foraging in the grass, just a few meters from the runway. He exits the car and aims the laser beam at the birds in turn. Immediately, the white birds fly away. We drive on, stop, and he points the laser beam at two crested cranes.

It had rained the entire morning, so as we drive over the stretch of the runway that is dark with rubber marks, Muhairwe radios Air Traffic Control again to report the condition of the tarmac, the runway lights, paint markings, and signage. This is the stretch where aircraft touch down. Entebbe, the bird attractant Entebbe has a rich bird environment due to the lake, wetlands, and open grasslands surrounding the airport.

The peninsula has two large swamps Kanyamusango and Namiiro and is surrounded by a number of islands that are habitats for birds. Entebbe also lies between Lutem- be and Mamamba bays, two designated Important Bird Areas and Ramsar Sites. This, according to Emmanuel Barungi, the general manager of Entebbe International Airport, makes the area more susceptible to bird strikes.

“The bird strikes here are as old as the airport. Of course, there are so many attractions to these birds such as the abundance of food. In our studies, we have come to learn that some of these birds come from as far as Europe, when the weather conditions are adverse,” he explains.

The Entebbe peninsula sits on the migratory path of birds moving in and out of the northern and southern hemispheres, and has a lot of vegetation which provide favourable roosting and breeding grounds. Many of the migrating birds make stopovers at or near the airport. Due to habitat loss in the northern hemisphere, increasingly, climate change is impacting the migration patterns of birds and the bird hazard control at airports.

Gloria Kirabo Bitebekezi, the principal bird hazard and wildlife control officer, says a high number of birds migrating, especially in the autumn and winter months, means a high number of bird strikes on aircraft.

“From November to February, the Bird Hazard and Wildlife Control Unit is on high alert, performing a lot more inspections and runway sweeps than usual. Besides the migratory birds, there are a number of bird species at, and around, the airport. Some of these include the black kite, swallows, egrets and ibis,” she says.

The bird strikes Barungi adds that the great danger of bird strikes comes from the big birds flying within the vicinity of the airport. “The level of danger to moving aircraft from doves, marabou storks, crested cranes, and eagles is great. This is because some of them weigh nine kilograms so when they hit the engine of the airplane, they are immediately sucked in,” he says.

However, not every strike causes damage to the aircraft. Bitebekezi says over the years, there have been innovations in the global aircraft manufacturing industry to combat the threat of bird strikes.

“These days, airplanes move quietly so many birds will be hit. However, they have also improved the engines. Some aircraft engines have been designed in such a sway that some birds can go through without damaging them. That is why we may have many bird strikes but minimal damage,” she says.

According to the online encyclopedia, Wikipedia, during a chicken gun test on aeroplanes, a compressed-air cannon fires dead chickens at aircraft components to simulate bird strikes and test aircraft durability. The most common targets for these tests are jet engines and windshields, which are vulnerable to damage from bird strikes.

“Land use management around the airport is also a challenge. We used to have a dumpsite very close to the runway but it was removed. That was a big achievement because you cannot have marabou storks feeding near the airport. So while we have many small birds coming in in flocks, the damage they cause is minimal,” Bitebekezi adds.

When birds strike an aircraft, a number of processes are set in motion. For instance, if the aircraft hits the bird during takeoff, the pilot will immediately inform Air Navigation Services, who will inform the Airside Operations department.

“Depending on the decision of the pilot, if he is returning to the airport, he will inform Air Navigation Services so that we are on standby to receive the aircraft. A detailed assessment of the damage on the airplane will then be performed,” Barungi says. The Bird Hazard and Wildlife Control Unit was operationalised in 1998. Before that, Airside Opera tions was doing some of the duties currently performed by the Unit.

“That Unit is highly regulated because it needs to be compliant with the required international standards. The effect of an airplane getting a hit that can bring it down is very huge. The airline company can run bankrupt due to the expenditure on extensive repairs on the aircraft or compensations that have to be paid in case there are deaths,” Barungi stresses.

This is why the Unit operates 24 hours a day, doing everything possible to guard against big birds striking a plane. The runway sweep Meanwhile, on the runway, Muhairwe drives the bird scare vehicle at a high speed.

So far, we have driven along the tarmac twice from the start to the finish. He stops suddenly after spotting a flock of birds in the sky. This time, he grabs the pyrotechnic pistol and loads a signal cartridge. Taking aim, he fires two blanks at the flock. The loud bangs scatter the birds. The smell from the pistol smoke is overpowering. Signal cartridges are a type of ammunition designed to provide high intensity aerial visual signals. In this case, they are to deter the birds.

Slightly ahead, we encounter a large flock of Egyptian geese. This time, Muhairwe plays distress calls from the car. These are sounds recorded when birds are in danger. The idea is to warn others of impending danger. The geese listen intently to the sound but stay put. Not even the laser beam dislodges them. They seem to have adapted to the sound.

“Birds, like humans, adapt. You will have a measure today and the birds will be scared for a while, but with time, they get acclimatised to it. Sometimes, not all the birds will leave the runway. We provide the information to Air Traffic Control, which then informs the pilot coming in to land. He or she will then make an informed decision,” Bitebekezi explains.

Bitebekezi adds that the runway sweep is the last point of contact with the tarmac before a flight takes off or lands. It is meant to perform a final dispersal of whatever is visible on the runway.

“We use a four-way approach, with the first being habitat management to discourage wildlife from coming to the airport. Most airports are like construction sites so we are always in touch with the contractors to ensure that there are no pools of water near the tarmac,” she says.

This is because birds are always on the lookout for food, shelter, water, and a place to breed.

“We manage their nests when we find them, removing them from the airside, especially if there are no eggs in them. Currently, we are cutting the grass around the runway down to 30cm, which does not encourage big birds,” Bitebekezi explains.

The other approach is to engage the community living around the airport in proper waste disposal because sometimes, the birds feed in the community and then travel to the runway to roost.

“We engage the two surrounding communities of Nakiwogo Landing Site and Kigungu Landing Site. We do not encourage gardening around the airport because crops attract birds and small animals. We also interest ourselves in the way the hotels and beaches around us manage their trash,” Barungi says.

The Airport Bird Hazards and Wildlife Committee includes representatives from the relevant departments at the airport, Uganda Wildlife Authority (UWA), Ministry of Agriculture, Animal Industry and Fisheries (MAAIF), Uganda People’s Defence Air Force (UPDAF), Special Forces Command (SFC), the Marine Forces, Entebbe Municipal Council, local council leaders and Beach Management Units.

“The airport is a closed space and most bird strikes happen outside the airport. Birds can hit an aircraft in Mpigi district as it is flying low, in preparation for landing. That is why we work with all those individuals,” Barungi adds.

The third approach is dispersal, which involves the runway sweeps and foot patrols. The latter are the best dispersal method because man presents a real danger to wildlife. The patrols use catapults and clappers to chase the birds.

“Our colleagues patrol the runway at a safe distance. However, the Unit conducts continuous research because with time, birds get used to certain methods. All the four approaches have to work hand-in-hand, because even if it is raining, we have to ensure the runway is safe for landing and takeoff,” Bitebekezi says.

COSTS, CHALLENGES

The Air Traffic Control radios Muhairwe and instructs him to vacate the runway. The Uganda Airlines flight is about to land, so he drives to a hidden section at the end of the tarmac. Here, a number of small birds roost on the tarmac. He calls Air Traffic Control again, to inform them of the bird activity.

“Those birds have refused to vacate the runway probably because they have young ones nearby. Airports need proper lighting, yet lights attract insects, which in turn, attract birds. So for habitat management, the signage on the runway and the solar panels surrounding it have spikes to discourage birds from perching on the flat surfaces,” Bitebekezi says.

Barungi says the pyrotechnic equipment used to chase the birds and wildlife rarely undergoes wear and tear, but when it does, replacing them is an expensive venture. “Some equipment needs input all year round. For instance, the ammunition used in the pistols and guns cannot be found in the region. There are few manufacturers of signal cartridges and pyrotechnic pistols so the process of transporting the equipment involves a number of protocols,” he says. Since the runway sweeps must be done before every takeoff and landing, purchasing the signal cartridges is very expensive.

“The Unit has enough manpower, although it requires many technical people. We have to ensure that they have the morale and are not grumbling. I have to keep monitoring the Unit to see how they are going about their work and whether the activities are being done correctly,” Barungi adds.

The Unit has a huge budget for training, sending employees overseas for trainings, due to the requirements of the International Civil Aviation Organization (ICAO) Once the Uganda Airlines aircraft lands and taxes to the terminal gate, Muhairwe drives the car back onto the runway for another high speed sweep.

This time, we encounter crested cranes, but there is no time because another radio message comes in instructing him to get off the runway. A huge aircraft is waiting to taxi on to the runway, in preparation for takeoff. We drive to another hidden section of the runway and wait for the airplane to take off.

Once it is airborne, we exit the runway. Because of the location of Entebbe, the primary focus is on conserving the bird species. However, since the Unit is not allowed to kill the birds on, or near, the runway, the challenge is in creating a safe environment for aircraft to operate, while conser- ving the ecological system and protecting bird-watching tourism.