OK, let’s first think about when a controller should use visual separation. ATC need to consider the following points before separating departing aircraft by visual means. Aircraft performance, wake turbulence, closure rate, routes of flight and known weather conditions. If successive departure routes or aircraft performance prevent the pilot from maintaining adequate separation then don’t apply visual separation of aircraft.
Now we need to consider a number of other factors – it must be day, the air-traffic controller must have both aircraft in sight and must be in radio contact with at least one of them. The flight crew of the trailing aircraft must have the lead aircraft in sight and be informed of the lead aircraft’s position, its direction of flight and its crew’s intentions. The pilots of the trailing aircraft must acknowledge sighting the lead aircraft and they will then be instructed to maintain visual separation.
It’s important for the pilots of the trailing aircraft to remember that the tower controller will not provide visual separation between aircraft when wake turbulence separation is required. In controlled airspace with ATC radar coverage, the controller must inform the pilot of converging aircraft and VFR traffic. In cruise, when IFR and VFR aircraft are sometimes separated by as little as 500 ft, pilots must use appropriate avoidance procedures.
Of course, the problem with wake turbulence is that it is nearly always invisible, so pilots need to anticipate where it might be. Remember, the weather is going to affect wake turbulence. If it’s still, then there is more chance of wake turbulence occurring.
Finally, remember your role. As air-traffic controllers you need to issue ‘Caution – wake4 turbulence’ warnings only. You are not responsible for anticipating the existence or effect of the condition.
TEXT 15 (2.05 – Track 15)
The most severe icing encounter I’ve ever experienced happened once when I was doing mountain flying in a Dash 8-200 model. It was -8°. This is the magic temperature. We started picking up super cooled large droplets at FL220. Within that first minute we had accumulated so much ice we had lost 15 kn. I could barely see out my left window at the boots and propeller.
In my experience, if you lose your windshield in the dash, it shows the ice is getting behind the de-ice equipment. I had the ice systems set at maximum and I lost my windshield completely. The airframe was vibrating and shaking violently and I knew we couldn’t climb out of it in time. We requested lower and when ATC cleared us I dropped the props to 1,200 rpm, switched off the autopilot and dove down at 4,000 ft per minute.
So, before we move on, have any of you had an icing experience?
TEXT 16 (2.08 – Track 16)
I = interviewer, P = pilot
What’s like to fly through a storm?
Actually flying into a storm is pretty nasty for the passengers and can be pretty scary for us. Flying in stormy conditions is always a challenge, but when you get active storm clouds at high altitudes, when there’s uplift and moisture in the clouds, it’s really tough.
If you can’t fly through them, do you fly around them?
Yeah, wherever possible. Flying through storms does happen, but I think most pilots would agree that it is pretty unusual to take an aircraft straight into a storm cell.
What do you do when you’re faced with storms?
If there is a line of storm clouds to fly through, you usually go for a gap in the line. We have a radar on board which senses water droplets, so we can see storm activity up ahead and plan for it. When visibility is poor, or you are flying at night, the radar is especially important. The problem is, the radar only senses water droplets. It can’t see turbulence, so even if you fly around a storm, it could still be a bumpy ride.
We know weather causes a lot of delays for airlines. Are storms particularly disruptive?
Yeah, weather is usually in the top three reasons for delay. I once had to circumnavigate a large area of showers over the western Pacific which was almost 300 nm out of the way. Definitely the longest diversion I ever had to make.
TEXT 17 (2.14 – Track 17)
Good morning. We’ve already looked at delays due to technical difficulties but today we’re going to focus on the weather. Bad weather causes far more delays than any other factor.
Commercial aircraft have a lot of restrictions and rules about operating in the vicinity of bad weather. Aircraft can’t take off unless the visibility at the destination airport is forecast to be at or above certain distance. Usually half a mile. Airlines take great care when bad weather is reported, because they want to prevent passenger injury. Two thirds of turbulence-related accidents occur at or above 30,000 ft. In fact 46% of all passenger injuries in flight are due to turbulence. This leaves airlines with little choice but to delay when bad weather turbulence approaches.
Although people think of the winter as being connected with bad weather it is usually spring and summer months which are the worst for bad weather delays. These month carry hot humid air, which produces dangerous thunderstorms, severe lightning and turbulence. In fact thunderstorms can contain just about every nasty aspect in one package.
The airport an aircraft is waiting to depart from might have perfect flying conditions but if the destination airport or the route has bad weather you may well have to delay the aircraft. During departure, you route the aircraft to a specific navigation point, the ‘departure fix’. If thunderstorms or other bad weather are lingering around this fix location, or elsewhere along the route of flight, or even at the destination, then you have to prevent departures to the affected area.
TEXT 18 (2.17 – Track 18)
Yesterday a passenger flight en route to Kiev had to make an emergency landing in Stockholm when an oxygen cylinder smashed through the skin of an aircraft.
The Boeing 747 jumbo jet was flying from Oslo to the Ukrainian capital with 384 passengers and 18 crew on board. It was cruising at 30,000 feet when the aircraft experienced a loss of cabin pressure. Passengers and crew report hearing a loud bang prior to the loss of pressure which was probably the cylinder exploding. The aircraft was forced to make an emergency landing at Stockholm where several passengers were treated for shock.
An immediate inspection revealed a rupture in the fuselage measuring one and a half metres. Investigators haven’t ruled out terrorist activity although no traces of explosive residue were found. Officials have said the most likely cause is failure of the seven oxygen cylinders found on the craft. The pressure from the failed cylinder sent it though the passenger cabin and out of the fuselage, narrowly missing a number of passengers.
In the past, external causes have resulted in blown cylinders. However, the faulty cylinder in this case hasn’t been recovered yet. The exact cause of the explosion is unknown, and it is likely to stay that way until investigators are able to find the cylinder.
TEXT 19 (2.20 – Track 19)
NA = newsroom anchor, R = reporter, P = pilot
A Western Pacific flight makes an emergency landing in Seoul after a passenger declares that the aircraft is falling apart. News East Kate Shamayoto is at the airport with more details of this strange case.
You just don’t expect things like this to happen. All of a sudden, a passenger in the very last row starts yelling that the aircraft is going to break up. Flight 76 was on it’s way from Busan to Beijing when it was forced to make an emergency stop in Seoul after flight attendants couldn’t get the man under control. The aircraft landed at around 6.30 last night.
I understand the flight attendants had some special help on board. What can you tell us about that?
Apparently there was quite a struggle and when the passengers saw that the attendants were struggling to control the man they jumped in to help. They said they had some difficulty getting him onto the floor, but no one was hurt. The passengers helped to hold him down while his ankles and wrists were handcuffed. When the flight eventually landed, Korean Police took the man away. So far we’ve not heard what’s going to happen to him.
We spoke to the flight crew yesterday evening. This is what the flight’s captain had to say:
He had a drink at the origin airport. He was on medication but didn’t take it. Perhaps a combination of not taking the medication, the drink and the altitude affected his usual behaviour. We diverted because we felt he was a threat to the safety of the flight.
Back to you in the newsroom.
TEXT 20 (2.23 – Track 20)
Latest news on the attempted hijacking of a Greek jet has led to conflicting reports from the airline and passengers. Yesterday we were told a middle-aged man attempted to hijack the jet and re-route it to Germany, threatening to blow it up if his demands weren’t met. The man, who hasn’t been named, demanded that the flight, from the Greek resort of Corfu, be taken to Munich in Germany. He was arrested after the aircraft reached its original destination of Kharkov. The would-be hijacker, in his early 50s, made the demand in a note to the pilot of the Airbus a-320, which was carrying tourists returning from the Mediterranean resort. The offender got out of his seat and handed the note to a flight attendant saying he had a bomb. The man then attempted to walk towards the cockpit. At this point he was overpowered by several passengers. The prosecutors’ spokeswoman did not name the man but said he was from a Central Asian region. This contradicts the statement by a Greek official that said he was a German national. The man did not have explosives and investigators are still seeking to determine whether he was drunk.
However some passengers are questioning official reports. They said they were on the flight and they didn’t notice anything unusual. They denied reports the man was drunk and said they didn’t see anybody fighting with passengers or cabin crew. In fact quite the opposite. The passengers reported the whole fight was calm and they didn’t notice anything unusual. It was only when they landed and saw armed police near the aircraft that they realized there was a problem. Some of the passengers had relatives waiting to meet them. They too saw the security personnel moving towards the aircraft and the passengers began to get worried telephone calls on their mobile phones.
An unconfirmed report has suggested that it was just an overreaction by a member of the cabin crew who was being harassed by the passenger.
TEXT 21 (2.26 – Track 21)
The crew did a thorough pre-flight briefing for a reduced-power take-off on runway 16, and the first officer was to be the handling pilot for the departure. During the take-off roll, the captain called for the first officer to rotate, but the aircraft was slow to respond with nose-up pitch. The captain called again to rotate, and the first officer applied greater nose up command. The nose of the aircraft then raised, and the tail made contact with the runway surface. The captain then selected TOGA, or maximum take-off thrust, the engines responded immediately, and the aircraft lifted shortly afterwards.
An inspection of the runway and the overrun areas identified multiple contact marks. The tail of the aircraft made contact with the runway at three locations. After leaving the stopway, two scrape marks were identified in the grassed area.
During take-off the aircraft also made contact with ground infrastructure. It clipped a runway 34 high-intensity centerline strobe light, and the left main landing gear inboard-rear tyre hit the runway 16 localizer antenna, the impact of which disabled the localizer function.
Significant damage to the aircraft included abrasion to the rear lower fuselage and damage to the rear pressure bulkhead. The abrasion actually wore through the full thickness of the skin. The inspection panel for the waste water drain point came off, and that panel was later found near the end of the runway.
TEXT 22 (2.31 – Track 22)
We were en route from Brussels to Vittoria and the flight engineer had just brought us coffee. Paris gave us a radar heading, and I placed my coffee on the footrest at the bottom of the instrument panel, then reached down to turn the heading bug on the CDI. As I did so, my hand caught the coffee and knocked the cup over. The coffee spread across the GPS, running between the buttons, and the screen started blinking. An error message appeared, then the screen went blank, flickering briefly and then went blank again.
I switched the GPS off before it started smoking or popping circuit breakers. Paris inquired whether we were on the heading, and I turned the heading bug. Bob, the co-pilot, pulled out the high altitude chart. On this the VOR and reporting points were in print so small that they were almost impossible to find. The charts were also not necessarily aligned to magnetic north, making it difficult to work out which direction you were going in, let alone where you were.
‘2434, direct Belen,’ Paris said. I turned right slightly, guessing which way it must be. It was more than 200 miles away, and not even on the same chart. Normally I’d never just punched it into the GPS.
Paris asked us for confirmation ‘… 2434, confirm routing direct Belen?’ We asked for a heading. They told us to turn right ten degrees and after ten minutes or so we managed to find where we were on the chart. We stayed on a radar heading until we picked up Bilbao VOR. We reached our destination without further difficulties and made a mental note to add cups of coffee to the list of things to watch out for on the flight deck.