Invisible threat

1.

INVISIBLE THREAT

2.

TURBULENCES
• 1. Nature of turbulences
• 2. Artificial turbulences
• 3. Separation Rules in turbulences
• 4. Accident A380-CL604, ICAO overview
• 5. Summary

3.

1. Nature of Turbulence
By the meaning the turbulence is the disruption in the air
current which leads a plane to fly results in shakes and it is
referred to as turbulence. Also known as air pockets turbulences
that can cause a sudden loss of altitude temporarily.
Severe turbulences causes large and abrupt changes in altitude
and/or attitude and, usually, large variations in indicated
airspeed. The airplane may momentarily be out of control.
Occupants of the airplane will be forced violently against their
seat belts.

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5.

MICROBURST
• In meteorology, a Microburst is a strong
downward and outward gushing wind system that
emanates from a point source above and
blows radially, that is, in straight lines in all
directions from the area of impact at surface level.
It originates under deep, moist convective
conditions like Cumulus
congestus or Cumulonimbus. Capable of producing
damaging winds, it may sometimes be confused
with a tornado, where high-velocity winds circle a
central area, and air moves inward and upward.
These usually last for seconds to minutes.
Microbursts are particularly
strong downdrafts within thunderstorms (or deep,
moist convection as sometimes downbursts
emanate from cumulonimbus or even cumulus
congestus clouds that are not producing lightning).

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2.Artificial Turbulence
Airplanes

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Differences of wings

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Helicopters

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3.Separation rules

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Aircraft Categories
• As weight is the main factor contributing to the generation of wake turbulence and also a crucial factor in the severity of
the effects of such turbulence, aircraft have been categorized according to their maximum certificated takeoff mass. In
Doc 4444 PANS ATM, ICAO defines three categories with a fourth one (Super Heavy) defined by a State letter:
• Super Heavy for Airbus A380-800 with a maximum take-off mass in the order of 560.000 kg

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4. Accident A380-CL604, ICAO overview
WP 25 - RVSM.pdf

17.

Accident A380-CL604
• The accident occurred just over 7 years ago, on January 7th, 2017. The
private jet that would later get caught up in an A380's turbulence was
a Bombardier Challenger 604 that, according to the Aviation Safety
Network, bore the registration D-AMSC. It had six passengers and three
crew onboard, and first flew in 2000.
• The aircraft's operator at the time was MHS Aviation, and it was flying
from Malé's Velana International Airport (MLE) in the Maldives to Abu
Dhabi's Al Bateen Executive Airport (AZI) in the UAE. Meanwhile,
the Airbus A380 whose turbulence it encountered was
an Emirates aircraft flying out of Dubai International Airport (DXB).

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• This double-decker quadjet bore the registration A6-EUL, and it was flying to Australia's Sydney
Kingsford Smith Airport (SYD) as Emirates flight EK412, a service that still operates today.
Interestingly enough, the Bombardier Challenger and the Airbus A380 departed just three minutes apart,
at 06:52 and 06:55 UTC respectively.
• As the two aircraft cruised towards their respective destinations, the Challenger 604 was flying at an
altitude of 34,000 feet. Meanwhile, traveling in the opposite direction, the A380 was just 1,000 feet
higher, at flight level 350. The two aircraft crossed paths at 08:38 UTC, while flying over the Arabian
Sea in Indian airspace.
• As the OPS Group notes, the turbulence generated by the Airbus A380 didn't impact the Challenger
immediately. Indeed, its effects were instead first felt some 48 seconds after their paths crossed, by
which time the two aircraft were already 15 NM (27.8 km) away from each other. Nonetheless, it
significantly impacted the jet.

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• Indeed, FAA reported at the time that the impacts of the superjumbo's wake turbulence had caused the
private jet to roll at least three times. This movement threw the jet's passengers and other objects around
the cabin causing multiple hospitalizations and one serious injury among those onboard the luxurious
aircraft.
• The Flight Safety Foundation notes that, equally terrifyingly, the aircraft also lost around 9,000 feet of
altitude as it rolled over and over in mid-air. The incident also caused multiple instrument failures, with
the pilots only able to tell the difference between the sea and the sky by identifying the presence of
clouds in the vicinity.
• Needless to say, it was imperative to get the aircraft on the ground promptly after such a serious
incident. As such, rather than continuing to Abu Dhabi as planned, the pilots of the stricken Bombardier
Challenger 604 instead opted to divert to Muscat International Airport (MCT) in Oman. Despite landing
safety, aircraft ultimately had to be written off and sold for parts.

20.

DESCRIPTION OF EVENT
• Statements of the CL604 Pilots According to the statement of the CL604 pilots the Pilot in command (PIC)
was Pilot Flying (PF) and the co-pilot Pilot Non Flying (PNF). The PIC stated that TCAS had drawn his
attention to the opposite traffic. He then recognized the aircraft type A380, the airline, and informed the copilot. The PIC also stated that the A380 had passed them in opposite direction, slightly to the left and
according to TCAS 1,000 ft above. He further stated that a short time later the airplane had been hit by the
wake turbulence of the A380. The airplane had shook briefly, then rolled heavily to the left and the autopilot
disengaged. Both pilots had actuated the aileron to the right in order to stop the rolling motion. But the
airplane had continued to roll to the left thereby completing several rotations. Subsequently both Inertial
Reference Systems (IRS), the Flight Management System (FMS), and the attitude indication failed.
According to the pilots' statements at the time of the accident both pilots had fastened their lap belts and in
addition the co-pilot had worn his shoulder belts. According to the PIC he had lost his headset during the
rolling motion of the airplane. The Quick Reference Handbook (QRH) had flown around the cockpit and
was damaged. As a result individual pages had been scattered around the cockpit. The PIC explained since
the sky had been blue and the ocean's surface almost the same color he had been able to recognize the
aircraft's flight attitude with the help of the clouds. Later both pilots had been able to recover the airplane at
FL240 using control inputs on the aileron and later the rudder and slight elevator deflection. Regarding the
left engine the PIC stated that he had observed that N1 and N2 had "run apart". N1 had decreased severely.
Interstage Turbine Temperature (ITT) had increased, reached more than 1,000°C, and the indication
flashed red. Subsequently the engine was shut off. Based on the memory items the pilots were able to
reactivate the IRS in attitude mode and fly the airplane again towards reporting point KITAL. Then the
pilots used the cross bleed of the right engine to restart the left. After the second IRS had been reactivated
and position and heading been entered manually into the FMS the autopilot was engaged again. After they
had assessed the situation the flight crew decided to fly to Muscat.

21.

ICAO overview
Strategic Lateral Offset Procedures (SLOP)-PANS-ATM 2.10 SLOP
are approved procedures that allow aircraft to fly on a parallel track to
the right of the centre line relative to the direction of flight to mitigate
the lateral overlap probability due to increased navigation accuracy
and wake turbulence encounters. Unless specified in the separation
standard, an aircraft’s use of these procedures does not affect the
application of prescribed separation standards.
Strategic lateral offsets shall be authorized only in en-route airspace
as follows:
a) where the lateral separation minima or spacing between route
center lines is 2,3 NM or more, offsets to the right of the center
line relative to the direction of flight in tenths of a nautical mile up
to a maximum of 2 NM; and
• b) where the lateral separation minima or spacing between route
center lines is 6 NM or more and less than 23 NM, offsets to the
right of the center line relative to the direction of flight in tenths of
a nautical mile up to a maximum of 0.5 NM.

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Summary
• ATC shouldn’t let happened this kind of situations,
Air Traffic Services Manual (РОВД), seen SLOP operations:
General rules for applying the operative lateral displacement procedure:
- only in the upper airspace;
- only to the right of the axis of the route or flight path at a distance of 1 or 2
NM. For deviations up to 3.7 km (2 NM), the aircraft crew is not required
inform the ATC.
- the decision to use SLOP is within the competence of aircraft crew and
pilots are required to inform the ATC unit that the flight performed with
operative lateral displacement;
- operational lateral displacement can also be initiated by the ATC unit.
- Note: Under no circumstances should you perform an offset to the left, except when this is due to factors
threatening flight safety.

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• BUT IT HAPPENED,
HE SHOULD BE ALWAYS READY FOR
ASSISTANCE.

25.

ATC IN SPECIAL CONDITIONS,
OUR TECHNOLOGY RULES, 5th part
CASES AND UNFORTUNATE CIRCUMSTANCES IN FLIGHT. (ТЕХНОЛОГИЯ РАБОТЫ 5-РАЗДЕЛ)
The variety of circumstances in each emergency situation makes it difficult to establish precise and detailed procedures.
The following procedures are intended as a general guide for the air traffic controller.
When receiving “Distress”, “Urgency” signals or a report of a failure/malfunction on the aircraft from the aircraft crew, the
controller is obliged to:
ATC immediately inform the aircraft crew:
location of the aircraft (if radar control systems are available).
Getting from the aircraft crew: If absence of radar systems or if the aircraft is outside the coverage area radar systems:
aircraft location, altitude and flight course;
nature of the emergency;
decision (intentions) of the aircraft crew;
transmit the received information to the Supervisor (senior controller) and Adjacent control centers in the direction of
the aircraft’s flight;
clear the airspace in the direction of flight of the emergency aircraft (if necessary);
introduce radio silence or transfer an aircraft in an emergency to another frequency (if necessary);
control the flight of an aircraft in an emergency situation using available ATC surveillance systems;
provide the aircraft crew with the required information (data on requested airfields, minimum safe altitudes,
meteorological information, etc.);
ensure, if possible, the shortest flight path to the intended landing point or to the nearest airfield;
inform other aircraft flying near the aircraft in an emergency situation about the current situation (if necessary);
in case of disappearance of the aircraft in radar, indicate the time and mark the place of disappearance;
act according to the instructions of the Supervisor (senior ATC) and depending on the current situation.