Manila VOR Fails

Cause Flight Delays and Cancellations

June 20, 2010

The Doppler VHF omnidirectional radio range(VOR) system of the Ninoy Aquino International Airport (NAIA) conked out Saturday morning causing massive delays and cancellations of some domestic and international flights with night arrivals.

Air Navigation Service (ANS) technicians have been trying to fix the navigational equipment since it stopped functioning at 7:30 a.m.

VOR is a navigational aid which helps pilots determine the correct approach to airports runway which are using the Instrument Flight Rules (IFR) and is particularly useful at night and during bad weather where visibility is poor.

Manila International Airport (MIA) General Manager Melvin Matibag said that heavy downpour could have possibly caused a short circuit in the 14-year-old equipment. The VOR was supposedly due for replacement this year but budget for its procurement was made until after next year. The equipment has an operational life of 15 years but requires constant checks and replacement of some parts. Replacement of defective part will already cost the agency some P90 million pesos at the current U.S. dollar exchange rates.

Meanwhile, Alfonso Cusi, Director General of the Civil Aviation Authority of the Philippines (CAAP), said that airlines can still use the airport even without the VOR but they have to follow published visual approach procedures.

The problem however comes in during night time and bad weather until after temporary replacements are made.

“Our radar and the distance measuring equipment are operational, our traffic controller can guide them until they reach the 5 miles and 1,500-feet aircraft altitude from the runway. If the weather permits and the approaching aircraft can see the runway, then they can land. If not, they have to divert,’’ says Cusi.

CAAP's Air Navigation Service (ANS) disclosed that “the power supply of the antenna tuning unit of the VOR went off, but we are still looking further into the source of the problem but stressed that the radar system is on normal operations”.

“We are now coordinating with Subic Bay Administrator Armand Arreza and they are more than willing to help us. They will give us their VOR since they are not using it anyway."

“Our technical team is now doing the repair work. For backup and to fix the equipment, we borrowed the power supply and antenna of Subic airport,” Cusi said.

The Subic airport VOR power unit arrived in Manila only around 3 a.m. Sunday. The installation of the power supply took a couple of hours and by dawn, technicians from the ANS started to power-up the navigation system.

CAAP technical assistant Lito Casaul explained that the power supply came from a similar but different navigation system, both in model and type and requires recalibration and testing before it can be installed on the VOR.

Limited night arrivals

While CAAP opted not to suspend NAIA's night operations contending that other navigational facilities such as radar and the distance measuring equipment (DME) were still working, airlines were not about to gamble their own safety as they rescheduled flights the following day affecting close to 20,000 passengers.

“On the occasion of heavy downpour, we have to suspend the night operations in the airport and advice airlines to cancel their flights,” Cusi said.

The thunderstorm and heavy rainfall over the airport at about 4 p.m. caused visibility to be reduced to zero, forcing pilots to land temporarily at the Clark International Airport while a Dragon Air flight from China canceled its arrival in Manila.

Hawaiian airlines flight from Honolulu has been diverted to Clark while three Philippine Airlines flights has also been diverted to Cebu and Clark airports. They were PR 425 from Fukuoka, Japan, was diverted to the Clark International Airport while the two domestic flights from Tacloban and Cagayan de Oro were diverted to Mactan.

The plane was supposed to land in Manila around 5:15, 7:40, 8:30 and 8:40 p.m respectively.

The weather cleared after 9 p.m. and the airport was re-opened for arrival of international flights to Manila.

"all airlines have already adjusted their incoming and outgoing flights in anticipation of unfavorable weather conditions" says Cusi.

There are 74 incoming flights last night until Sunday morning but there are 155 international and domestic flights that will be affected until Monday the next day if the VOR is still inoperable says Cusi.

"Philippine Airlines flights coming from the United States and the Middle East have been delayed. Foreign carriers like Emirates and Ethihad are also delayed until Sunday morning. Some domestic flights of PAL, Cebu Pacific and Zest Air have also been canceled" said Cusi.

Cathay Pacific flights from Hong Kong, Qantas Airlines from Melbourne, Australia and Saudia Airlines landed safely at the airport after some delays. Shenzen Airlines of china also manages to land from Canton.

Philippine Airlines also announced that all of its inbound and outbound daylight flights operating out of Manila will remain normal but expects some delay.

“PAL is closely coordinating with the airport's traffic control to be able to operate PAL's night flights scheduled to depart/arrive after sunset,” a PAL advisory reads.

“Flights coming from the US scheduled to arrive early tomorrow morning are being rescheduled to arrive after sunrise, which is set at 5:28 a.m.

These flights are the following: PR105 San Francisco-Manila (ETA 5:40 a.m.), PR103 Los Angeles-Manila (ETA 6:00 a.m.), and PR117 Vancouver-Manila (ETA 5:50 a.m.). All other early morning arrivals are also delayed until sunrise.

On the other hand, Cebu Pacific announced that 28 of its domestic and international flights have already been canceled. Its international flights due to arrive on early Sunday has also been delayed until after sunrise.

“Thirty domestic flights were canceled on Saturday after the communications system of the Naia encountered technical problems,” said Candice Iyog, Cebu Pacific’s marketing head.

The VOR is scheduled to be fixed by 8 a.m. Sunday.

Recalibration and Testing

“The technicians cannot just power up the system and go. They have to slowly power up each of the system’s component to check if everything is working properly. If and when the system proves to be ok, they can then begin to reconfigure the unit,” Casaul said.

He said they have extended the Notice to Airmen (NOTAM) they issued Saturday morning to last until 8 a.m. Monday (June 21).

“We extended the NOTAM until Monday to give our technicians enough time to get the system up and running.”

“Hopefully, we can have the system up before sundown so we can resume with normal operations at the two runways,” Casaul said.

With the VOR inoperable, pilots have to rely on Visual Flight Rules (VFR) to land – meaning pilots would have to rely on the radar and other visual aids such as the runway lights in order to see the where to land.

The pilots could have done easily even without VOR and rely on the airport’s Instrument Landing System (ILS) for guidance but unfortunately, the ILS at the NAIA is currently being replaced.

Matibag, in a press conference, admitted that the Instrument Landing System (ILS) had been out of commission for weeks and the replacement for the $2.4-million equipment was delayed because the eruption of the Iceland volcano canceled the flights to Europe, where the parts are to be acquired.

He explained that maintenance of the ILS and the DVOR belong to CAAP, but it was MIAA that provided the fund for its replacement.

Installation of the ILS, originally set on May 29, has been reset to July.

The ILS equipment which  beams radio signals at the end of runway 24, provides accurate information to alert the pilot whether his aircraft is within a narrow band of horizontal and vertical clearance that would eventually bring him to the end of the runway.

With the advent of Habagat season, wind blows from west to east forcing airlines to land against the wind and requires the use of runway 24 for its approach.

In the absence of the ILS, radar controllers bring the aircraft to the end of the runway, near enough for the runway to be visible; and at night, when the runway lights are clearly in sight.

With both the VOR and ILS navigational systems down, the CAAP was forced to implement stricter rules on night landing and made the separations between airplanes much longer apart.

During normal operations, flight separation between aircraft are less than one minute. However, with the limited operations Saturday night, airplanes had to be separated by a minimum of five minutes to assure their safety.

CAAP also said that airline companies have discretion if they would allow their pilots to proceed to land at the airport even with the limited navigational aids. Matibag however said that should bad weather come into play, the Manila Control Tower will be forced to deny pilots permission to land and instead instruct them to divert at nearby Clark.

Manila airport is expected to be back to normal operations Monday morning. New VOR facility is valued at P120 million.


  1. "NAIA is deteriorating fast, what a big embarrasment for this country..."

  2. Even worse:
    “We are now coordinating with Subic Bay Administrator Armand Arreza and they are more than willing to help us. They will give us their VOR since they are not using it anyway."

    Which means another step towards closing Subic airport.

    It´s like fixing a hole by raising one at another place ...

  3. This is merely a stop gap measure as a new VOR will be in place next year. So the Subic VOR will be returned, or shall we say its power unit.

    As of 4 p.m., the Subic VOR was already installed but still not working because it has to be re-calibrated and configured correctly for NAIA frequency.

    The ANS Engineers said there is more problem to it than they previously thought and are still working out a temporary solution otherwise the power supply from Subic might blow off again.

  4. On 5J Domestic Cancellations

    GM Matibag said he was upset by the 5J cancellations because they make it appear that NAIA airport was closed when its not. More than 3,000 passengers were affected by Cebu Pacific's decision to cancel some of its domestic flights Saturday.

    "I think Cebu Pacific advisory is personally unacceptable because CAAP did not close NAIA" says Matibag.

    All foreign flights have landed and left safely last night without any problems other than announced delays.

  5. Kakahiya pinas. The only visual international runway in the world. Only in the philippines. If gma can only part her kurakot to buy a new vor and ils. Tsk tsk God help us.

  6. I wonder how some airlines get away with it. Pretty sure u can't legally intend to fly to an airport with ZERO approach navigation aids especially at NIGHT. You are never really VISUAL with the ground at night. The lawyers will be lining up the moment an accident happens.

  7. Why relying on DVOR for safe landing? It is only used for non-precision approach. I guess NAIA has Instrument Landing System (ILS) installed which is more precise than the DVOR for landing.

  8. RPLL has NO DVOR and NO ILS. And with a history of radar system failures, you'll be worried about whether the airport administrators are managing our airports competently? credibly? or neither!

  9. It's pathetic that MIAA in a TV interview is washing its hands about Cebu Pacific's flight disruptions. The VOR is a safety equipment, without it, there's no telling about what catastrophe can happen, God forbid! I wonder why MIAA has irresponsibly allowed its equipment to deteriorate; airlines pay them so they owe a level of service and professionalism! This points to the inefficiency of the GMA government!

  10. "NAIA runways are just waiting for that one big moment to happen which will kill hundreds of people...GOD FORBID!"

  11. "Matibag, in a press conference, admitted that the Instrument Landing System (ILS) had been out of commission for weeks"

    As far as I know, it's been out for more than 3 years now! Airlines pay NAIA for landing fees and its a shame it does not offer the same standard safety levels of a busy and premier aiport of the country!

    The downplay and the lies is what annoys and worries me about these officials. You're right, fingers eventually point to GMA.

  12. sabi din ni Matibag, "may radar naman at kaya dapat ng mga piloto kahit walang VOR"

    Asa ngayon sya sa galing ng mga radar controllers at sa mga piloto dahil sa kapalpakan nila.

  13. This is crazy. Probably the only international airport in the world without any navigational aids for landing. I went through the landing charts. ILS 06- not working, ILS 24- not working,
    Vor 06/24...well the vor is dead.
    Good Luck NAIA. Hope they got money to pay the claims.


  15. Rule of thumb: The successor is the one responsible to handle or resolve such problem of the previous management. This is politically motivated as business as usual.

  16. I was on PR flight 307 from Hong Kong Wednesday night (June 23/10)landing about 8:30 PM. Manila papers and TV were reporting that the equipment was operating. We flew three circuits around the airfield before landing. There were low rain clouds at the time and the ground was intermittently visible to us. Looked to us like the equipment was NOT working. I think the pilots landed the first time they had a clear view.