Tackling the Harmattan Haze

Operators in the aviation industry believe that with the right equipment, aircraft can fly under zero visibility, Chinedu Eze writes

The Airline Operators of Nigeria (AON) said last week that harsh operational environment, which include lack of airfield lighting in most airports, deficient and obsolete airport facilities, poor and obsolete navigational aids force airlines to cancel about 50 per cent of their flights daily.

Flight Cancellations

According to informed source, total daily domestic flights of all the airlines is about 200 but 50 per cent of these flights are cancelled mostly due to the infrastructural inefficiency and bad weather. To make the matter worse, every year Nigerian airlines cancel most of their flights during the peak period of December and early January due to the Harmattan haze, which gives rise to low visibility and brownish thick haze, that appears when the sun shines on the atmospheric dust during the day. During this peak period of the yuletide, all the domestic airlines barely operated any flights.

Poor Navigational Aids

The Chairman of Airlines Operators of Nigeria (AON), Captain Nogie Meggison said most navigational aids at the airports are not working because they are obsolete and in Nigeria the airports have Category 1 Instrument Landing system (ILS), which means that flights cannot operate when the weather is below 800 meters visibility, depending on the airport.
He said that many of the airlines have grappled with suspension of operations due to the difficulty they go through and the failure of government to take action to rectify these problems.

“On December 27 visibility in Lagos was about 500 meters so most international and local flights had to be diverted to Cotonue (Tuesday night), which is rather unfortunate. The issue of the harmattan haze is a yearly seasonal occurrence as Nigeria has mainly raining (Thunderstorms) and dry seasons (Harmattan).

“If the world has been landing in zero or virtually no visibility since December 28, 1968, today 48 years later on December 28, 2016 on the anniversary of the first Category 3 landing at Heathrow Airport, London, Nigeria still can’t land below 800 meters of visibility. Why are the navigation aids not working or upgraded over the years? Why is there no solution to this issue after 40 years of the airlines crying out? It is rather shameful that today in the 21st Century, we are still talking of operating at CAT l and unable to land at below 800m at our airports,” Meggison said.

He disclosed that for three days (26-28 December 2016) the Murtala Muhammed International Airport, in Lagos was shut down until 6:00 pm before flights could land. Hence no airline could fly and passengers were delayed with colossal loss of revenue to the operators.

“This is very unfair to operators who cannot charge passengers for the extra cost the airline has to bear on return or cancelled flights and we have to feed and lodge them in a hotel. The Nigerian Airspace Management Agency (NAMA) and the Federal Airports Authority of Nigeria (FAAN) need to be more responsible to ensure that our airports are equipped with the right landing aids to allow 24 hours operations in any weather condition,” Meggison said.

NAMA
In reaction to AON condemnation of obsolete and dysfunctional navigational aids, NAMA issued a statement on December 29, 2016 and argued that the major reason why airlines could not land at low visibility was because their aircraft do not have corresponding equipment to dovetail with the navigational aids the agency has on ground.

The agency called on the airlines and reminded them that it had earlier taken appropriate measures to ensure the availability and reliability of air navigation facilities at all airports.

“In addition, the agency in October 2015 implemented and published Performance Based Navigation (PBN) flight procedures for the guidance of aircraft into and out of 16 domestic airports in addition to similar procedures implemented at Lagos, Kano, Abuja and Port Harcourt in 2012. The agency wish to use this opportunity to encourage Nigerian airline operators to equip their fleet and take advantage of these new PBN flight procedures, as well as other satellite based navigation systems such as Automatic Dependent Surveillance Contract (ADS-C) and Controller Pilot Data
Link Communication Systems that were implemented in 2015, with increased level of safety, accuracy, reliability, integrity, availability and continuity of service,” NAMA said.

But pilots, who spoke toTHISDAY said NAMA was being clever by half because the agency knows that there are other corresponding facilities needed to make PBN work besides airlines having certain equipment in their aircraft. They said that even some of the basic navigational equipment are not working in most of the airports.

Deficient Navigational Aids

THISDAY also spoke with the former Managing Director of NAMA and currently the Deputy Managing Director of Arik Air who is a seasoned pilot, Captain Ado Sanusi who gave details why airlines do not operate at low visibility in Nigeria.
“There are two ways you can land in the Nigerian airports: precision approach and non-precision approach. These could be visual approach or navigation aided approach. Now, in most of the airports we have in Nigeria, there is either a VOR (VHF Omni Directional Radio Range) or ILS (Instrument Landing System). In most modern commercial aircraft they have VOR receiver and ILS receiver and INS (Inertial Navigation System), which is a self-positioning system for the aircraft.

“What we are talking about is ILS. Most modern commercial aircraft have instrument landing system receiver onboard and we must have corresponding ground equipment that will propagate the lateral guidance, the localizer, and the vertical guidance called the glide slope,” Sanusi explained.

He said that most aircraft operating in Nigeria have INS and modern aircraft have GPS (Global Positioning System which works with satellite), “so when they (NAMA) claim that most aircraft don’t have equipment onboard that will match the ground equipment, it means the aircraft does not have ILS receiver. But I don’t think this is possible because most commercial aircraft have ILS and VOR receivers onboard, which they use to conduct approaches.”

He said there is another form of approach, a navigational system called Performance Based Navigational System (which NAMA referred to in its statement). This one allows somebody to use R-NAV (Area navigation, which is a method of instrument flight rules (IFR) navigation approaches). R-NAV is approach aided with GPS (Global Positioning System). It is R-NAV approaches on an instrument flight rules (IFR) using only the GPS in aircraft to land at a low visibility situation.

“All the airports in the country have R-NAV approaches, but the Nigerian Civil Aviation Authority (NCAA) has to license each operator for that operator to conduct those types of approaches in all the airports. This is because there is need for special training and special equipment in the use of GPS. In this situation, there is no ground equipment needed for R-NAV approaches. This is because such landing is utilising GPS, which is satellite based and it is always calculating the performance of the aircraft, in terms of how accurate its position is based on the satellite. The moment it moves out of the parameters of accuracy, the GPS will warn you and you correct it.”

On Ground Equipment

Sanusi explained that what the NAMA has on ground is either VOR or ILS and said the ILS ought to have the localizer and the glide slope, adding that all the commercial aircraft built must have those receivers on board.

“If NCAA approves or authorises it, some airlines can land their aircraft at low visibility below the presently given minima. But they cannot land on zero visibility. For you to land on zero visibility you must have ground equipment. You must have category 3 ILS minimum. With NCAA approval airlines whose aircraft have GPS can do R-NAV approaches. This means they can go for Performance Based Navigation and R-NAV approaches.

“To land at zero visibility there must be Category 3 approach, which is a positioning approach. This is a positioning instrument approach and landing with position instrument lower than 100 feet. First of all you must have Category 3 ILS and Category 3 C approach is a precision approach with no decision height and no runway visual range, which is zero visibility,” Sanusi said.

Confirming what Meggison said, Sanusi noted that aircraft could land in Cotonou, Benin Republic at low visibility because they have Category 2 ILS, noting that what Nigeria has is Category 1and stressed that the ILS in Nigeria are Category 1.

Interagency collaboration

Sanusi noted that to operate aircraft at low visibility, it is not only NAMA that will provide the equipment. It cuts across the Nigeria Meteorological Agency (NIMET) and the Federal Airports Authority of Nigeria (FAAN). NIMET ought to provide the runway visual range, which is a form of measuring visibility at the beginning, middle and end of the runway. So NIMET must give the Runway Visual Range. Then FAAN has to provide airfield lighting. There is standard airfield lighting for low visibility landing, which includes centerline lighting, which Nigeria does not have. There is centerline lighting in the runway and the taxiway lighting.

“This means that in totality, we are ill equipped for low visibility landing in Nigeria and those responsible are FAAN, NIMET and NAMA. There should be inter agency meeting to make sure the equipment are okay for us to declare low visibility in an airport. They will now announce on the control tower that low visibility is in operation in these airports,” former Managing Director of NAMA said.

Sanusi therefore advised government to provide Category 3 equipment so that during Harmattan it will be deployed at the airports.
“It is very expensive to maintain Category 3 A Instrument Landing System because of the maintenance of runway field lighting and maintenance of power because power supply is very, very important. You cannot afford to have power supply interruption when landing at low visibility. It could be expensive to maintain it for 12 months in a year. The critical time we need this equipment is in December, so why don’t we have the capacity to have that Category 2 or Category 3 ILS and we make sure that just before December and after that the equipment is maintained and effectively running and resort to Category 1 thereafter.”

He said that is what Ghana does at the Katoka International Airport, Accra. They downgrade it to Category 2 or Category 1 after the Harmattan season. But on approach to Harmattan they do all the maintenance and make sure everything is in place. They now upgrade it and then send a NOTAM (Notice to Airmen) that from this period there will be Category 3 landing system in Accra. Analysts believe that Nigeria has the resources to make this possible but may lack the political will and commitment to do so.