VATSIM 5xx? ? ETOPS (Extended Range Twin Operations)

By Mark McGrath

GRAPHIC CONTENT MISSING, see http://mbev.net/bev/ETOPS.pdf∞

ETOPS = Extended Range Twin Operations. A flight is defined as being an ETOPS flight when it?s routings takes it more than 1hour?s flying time from the nearest suitable diversion airport, at the approved single engine cruise speed (under standard conditions and in still air). The ETOPS portion of the flight begins the first moment it is over this 1 hour flying time and ends the last moment the flight is out with this 1 hour flying time.

The 1st ETOPS Authorized flight took place on the 1st of FEB 1985 and was operated by a TWA Boeing 767-200 flying between Boston and Paris, a distance of 2986nm.

Non ETOPS - the 60 minute Rule
Before the introduction of ETOPS, flights by twin engine aircraft had to operate within 60 minutes flying time of the nearest suitable airport along the route. As can be seen in this diagram, this restricted the routings that twin engine aircraft could take.


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120 Minutes ETOPS
When ETOPS was first introduced, it was to the 120 minute rule - a twin engined aircraft needed to remain within 120 minutes of a suitable alternate. The 20 minute rule has subsequently been updated to become 120minutes + 15% or more accurately 138 minutes. With the introduction of 120 minute ETOPS more direct and quicker routes could be introduced by twin engined aircraft. This opened up the possibility of previously unserved markets receiving long haul flights. In the 1990?s, the Boeing 767 model was the most popular aircraft operating across the North Atlantic. The first ever ETOPS flight was conducted under the 120 minutes ETOPS rules.


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180 Minutes ETOPS
After ETOPS had been in operation and monitored by the aviation authorities, the time limit was increased to 180 minutes flying time from the nearest suitable airfield. With the new 180 minute ETOPS rule, more routings became available, including more direct routings from Europe to the Caribbean and South America, and the USA to Hawaii.


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Selecting a Suitable En route Alternate
An ETOPS alternate airfield must meet the following criteria during the flight planning phase:

• RFF minimum of ICAO Category 4.
• Minimum of 1 Published Approach Procedure - excluding GPS based approaches.
• Weather forecast to be above the following minima

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Note that if the ILS Minima are CAT II or above, then these Minima can be used for planning - e.g. the DH for a CAT II ILS would be 100ft, then you would add 200ft giving a ceiling of 300ft.

Equal Time Point and Critical Point
The ETOPS flight plan requires the calculation of Equal Time Points along the route. The minimum number of ETP?s on a flight is 1 based on the 180 minute ETOPS rule. Most flights operating to the 120 minute ETOPS rule will have 2 ETP?s.
What exactly is an Equal Time Point?
An equal time point is effectively a point of no return. Before reaching the ETP if you needed to divert you would divert to Airport A, after the ETP you would divert to Airport B.
The flight planning software used by airlines uses complex formulae to work out exactly where the ETP?s for a specific flight are. There is no easy way to calculate where along the route an ETP would fall.

The Single Engine Still Air Cruise Speed used to calculate the ETP?s is 400KTS TAS. Some airlines use a slightly higher or lower speed depending on their flight planning software.

The Critical Point is one of the ETP?s of the route which is critical in regards the ETOPS fuel requirements if you are required to divert at this point. The Critical Point is usually (but not always) the last ETP within the ETOPS portion of the flight plan. The Critical Point is carefully calculated by calculating the fuel burn from Departure to the ETP and from the ETP to the Diversion Airports.

Manual calculation of Critical Points
You will need a plotting chart to do this.

Plotting of the Critical Fuel Point manually may be achieved using the following method:

• Bisect a line drawn between the two most favourable suitable alternates furthest along track.
• Drop a perpendicular line from the point of bisection to cross the aircraft track. This will give the Still Air CP.
• Measure the distance to either alternate from this point. Then divide by 350 (kts G/S). Multiply the resultant by the 10,000' wind (in kts) and draw a vector of this length (nm) into wind from the still air CP.
• Construct another line, parallel to the original perpendicular, from the end of the wind vector to cross the A/C track. This point is the CRITICAL FUEL POINT (CFP).

This procedure is illustrated in the following diagram:


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If accurate meteorological data is not available for the route, the statistical 10,000ft winds to be used for these calculations are contained in the following table:
Note this is for RTES to/from Europe, North America and the Caribbean.

NORTHERN ROUTES (N OF 55?N)
WESTBOUND 210/12 230/6 260/10 250/14
EASTBOUND 220/14 240/10 260/12 240/16

SOUTHERN ROUTES (S OF 55?N)
WESTBOUND N/A
EASTBOUND 260/20 260/14 280/20 270/20

CARIBBEAN
NORTH/SOUTH 270/25 250/19 210/4 240/16


ETOPS FUEL Planning Calculations
Standard fuel planning procedures should be used from the departure airfield to the critical point.
ETOPS regulations require additional ETOPS specific fuel reserves to the ETOPS diversion fuel.
The Diversion Fuel planning should include the following fuel allowance:

• Fuel Burn from the Critical Point to the Diversion Airport - (for planning purposes 1,500ft overhead the airport).
• 15 minutes of holding fuel at 1,500ft.
• 1 IFR approach, followed by a go-around and a second VFR approach.
• 5% of the fuel burn-off from the CP to the diversion airport as contingency fuel.
• 5% fuel mileage penalty.
• Application of any CDL/MEL fuel penalties.
• 10% of the total if Engine and Wing Anti Ice are required - both engines running

The ETOPS fuel planning criteria should be calculated for each ETP on the flight plan. There are 2 critical scenarios for fuel planning - scenario 1 is Engine Out and diversion at Single Engine Cruise speed and scenario 2 is Rapid depressurization and divert at 10,000ft to the nearest suitable airfield.
In most cases, scenario 2 provides the higher fuel burn and is considered the most critical scenario.
In both scenarios, the critical fuel is based on an emergency descent to 10,000ft.
The following tables allow you to work out the Critical Fuel requirements at the Critical point for each scenario.

Single Engine 350 KIAS Cruise Critical Fuel Reserves


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• Add 13% if Engine and Wing Anti Ice is required due to Icing Conditions.
• Add 0.5% for every 10 degrees above the ISA.

All Engines Operating LRC Critical Fuel Reserves


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Displaying ETP?s during the flight.
The ETP?s are entered in one of two ways.

1. By using the second route to create a fictional route connecting all the ways points to destination E.g. EINN-ETP1-BIKF-ETP2-CYYR (The ETP's being entered in Lat/Long). This way you can view where you are in the game plan by seeing the lines in blue when viewing route two legs.
2. By entering the ETP's at the back of the legs page after the diversion route is complete. This is a bit of a cheat as if you don't intentionally leave a space after the go around then the FMC will predict ETA/Arr Fuel based on a return to mid Atlantic!! The trick is to input another waypoint in between and then delete it. E.g. ETP1 (Let/Long) enter GOW, delete GOW, leave the discontinuity, repeat for the second ETP. This will then see End of GA/Disco./ETP1/Disco/ETP2

The ETP's will then appear on the map as you cross them in route one, but will not be entered into the FMC calculations. (Neat Trick huh?)

The Diversion fields with their 400nm arcs are entered into the FMC fix page if desired.

North Atlantic Track System
Due to the large number of flights operating across the North Atlantic, there exists a series of Westbound and Eastbound Flight Routes. These routes are referred to as Tracks. The Westbound Tracks are used by flights flying from Europe to North America, and are valid between 1130 UTC and 1900 UTC daily. The Westbound tracks begin with the letter A, and are named in sequence - A, B, C etc. The Eastbound tracks for flights from North America to Europe become valid at 0100 UTC and are valid till 0800 UTC the next day. The Eastbound tracks begin with V, and are again named sequentially. The Actual tracks change on a daily basis, based on the predicted weather over the North Atlantic. The routings are determined by the Oceanic control center?s at Shanwick and Gander.
To ensure that crews are using the correct days NAT Tracks, a unique identifier number is issued for each days tracks. In the example NAT Tracks that follow, the TMI (Track Message Identifier) is 298.


241329 KCFCZDZX
ATCSCC ADVZY 019 DCC 10/24/05 NORTH_ATLANTIC_ROUTES_RQD
ZBW NORTH ATLANTIC ADVISORY
VALID FOR 10/24/05 2000Z - 10/25/05 0500Z

AIRCRAFT DEPARTING JFK PLEASE FILE THE FOLLOWING ROUTES TO MINIMIZE
DEPARTURE DELAYS DESTINED TO EUROPE:
TRACK V/ JFK.MERIT3.PUT..BOS..TUSKY.N55B.YYT.TRAKV
TRACK W/ JFK.BETTE3.ACK..BRADD.N45B.COLOR.TRAKW
TRACK X/ JFK.BETTE3.ACK..KANNI.N37B.BANCS.TRAKX
TRACK Y/ JFK.HAPIE3.YAHOO..WHALE.N29B.RAFIN.TRAKY
TRACK Z/ JFK.HAPIE3.YAHOO..VITOL.N21C.JAROM..BOBTU.TRAKZ

---

AIRCRAFT DEPARTING EWR PLEASE FILE THE FOLLOWING TO MINIMIZE
DEPARTURE DELAYS GOING TO EUROPE:
TRACK V/ EWR..MERIT..HFD..PUT..BOS..TUSKY.N55B.YYT.TRAKV
TRACK W/ EWR..MERIT..HFD..PUT..BOS..BRADD.N45B.COLOR.TRAKW
TRACK X/ EWR..MERIT..HFD..PUT..BOS..KANNI.N37B.BANCS.TRAKX


241301 CZQXZQZX
(NAT-1/2 TRACKS FLS 320/400 INCLUSIVE
OCT 25/0100Z TO OCT 25/0800Z

PART ONE OF TWO PARTS-

V YYT NOVEP 48/50 50/40 52/30 53/20 MALOT BURAK
EAST LVLS 320 330 340 350 360 370 380 390 400
WEST LVLS NIL
EUR RTS EAST NIL
NAR N55B N59A-

W COLOR RONPO 47/50 49/40 51/30 52/20 LIMRI DOLIP
EAST LVLS 320 330 340 350 360 370 380 390 400
WEST LVLS NIL
EUR RTS EAST NIL
NAR N45B N49A-

X BANCS URTAK 46/50 48/40 50/30 51/20 DINIM GIPER
EAST LVLS 320 330 340 350 360 370 380 390 400
WEST LVLS NIL
EUR RTS EAST NIL
NAR N37B N41C-

Y RAFIN VODOR 45/50 47/40 49/30 50/20 SOMAX KENUK
EAST LVLS 320 330 340 350 360 370 380 390 400
WEST LVLS NIL
EUR RTS EAST NIL
NAR N29B N33C-

END OF PART ONE OF TWO PARTS)



241302 CZQXZQZX
(NAT-2/2 TRACKS FLS 320/400 INCLUSIVE
OCT 25/0100Z TO OCT 25/0800Z

PART TWO OF TWO PARTS-

Z JAROM BOBTU 44/50 46/40 48/30 49/20 BEDRA GUNSO
EAST LVLS 320 330 340 350 370 380 390 400
WEST LVLS NIL
EUR RTS EAST NIL
NAR N21C N25B-

REMARKS:
1.TRACK MESSAGE IDENTIFICATION NUMBER IS 298 AND OPERATORS ARE
REMINDED TO INCLUDE THE TMI NUMBER AS PART OF THE OCEANIC
CLEARANCE READ BACK.

2.CLEARANCE DELIVERY FREQUENCY ASSIGNMENTS FOR AIRCRAFT OPERATING
FROM MOATT TO BOBTU INCLUSIVE:
MOATT TO SCROD 128.7
OYSTR TO CYMON 135.45
YQX TO YYT 135.05
COLOR TO BANCS 128.45
RAFIN TO BOBTU 119.42

3.80 PERCENT OF GROSS NAVIGATIONAL ERRORS RESULT FROM POOR COCKPIT
PROCEDURES. ALWAYS CARRY OUT PROPER WAYPOINT CHECKS.

4.OPERATORS SHOULD NOTE THAT NERS IDENTIFIER IS NOT TO BE INCLUDED
IN FIELD 15 OF THE FLIGHT PLAN UNDER ANY CIRCUMSTANCES.

5.PERMANENT NAT FLIGHT PLANNING RESTRICTIONS IN FORCE FOR AIRCRAFT
TRANSITING BETWEEN NEW YORK OCEANIC AND CANADIAN DOMESTIC
AIRSPACE. REFER TO NOTAM CZQX A5922/05.



242028 EGGXZOZX
(NAT-1/2 TRACKS FLS 310/390 INCLUSIVE
OCT 25/1130Z TO OCT 25/1900Z
PART ONE OF TWO PARTS-
A BALIX 61/20 61/30 61/40 60/50 59/60 LAKES
EAST LVLS NIL
WEST LVLS 310 320 330 350 360 370
EUR RTS WEST NINEX
NAR N412B N424E N426E N428C N434C N436A-
B ERAKA 60/20 60/30 60/40 59/50 PRAWN YDP
EAST LVLS NIL
WEST LVLS 310 320 330 350 360 370
EUR RTS WEST ETSOM
NAR N322B N326B N328C N334C N336H N346A N348C
N352C N356C N362B-
C GOMUP 59/20 59/30 59/40 58/50 PORGY HO
EAST LVLS NIL
WEST LVLS 310 320 330 340 350 360 370 380 390
EUR RTS WEST GINGA
NAR N284B N292C N294C N298H N308E N312A-
D NIBOG PIKIL 57/20 57/30 56/40 54/50 CARPE REDBY
EAST LVLS NIL
WEST LVLS 310 320 330 340 350 360 370 380 390
EUR RTS WEST NURSI
NAR N202B N206C N210E-
E MASIT RESNO 56/20 56/30 55/40 53/50 HECKK YAY
EAST LVLS NIL
WEST LVLS 310 320 330 340 350 360 370 380 390
EUR RTS WEST DEVOL
NAR N184B N188B N192C-
END OF PART ONE OF TWO PARTS)



242029 EGGXZOZX
(NAT-2/2 TRACKS FLS 310/390 INCLUSIVE
OCT 25/1130Z TO OCT 25/1900Z
PART TWO OF TWO PARTS-
F 41/40 35/50 30/60
EAST LVLS NIL
WEST LVLS 320 340 360
EUR RTS WEST NIL
NAR NIL-
REMARKS.
1. TRACK MESSAGE IDENTIFICATION NUMBER IS 298 AND OPERATORS ARE
REMINDED TO INCLUDE THE TMI NUMBER AS PART OF THE OCEANIC CLEARANCE
READ BACK.
2.PERMANENT NAT FLIGHT PLANNING RESTRICTIONS IN FORCE FOR AIRCRAFT
TRANSITING BETWEEN NEW YORK OCEANIC AND CANADIAN DOMESTIC AIRSPACE.
REFER TO NOTAM CZQX A5922/05.
3.ALL OPERATORS ARE REMINDED OF THE NECESSITY TO PROVIDE VOICE
REPORTS
OF ANY OBSERVED NON ROUTINE WEATHER PHENOMENA.
4. MNPS AIRSPACE EXTENDS FROM FL285 TO FL420. OPERATORS ARE REMINDED
THAT SPECIFIC MNPS APPROVAL IS REQUIRED TO FLY IN THIS AIRSPACE.
IN ADDITION, RVSM APPROVAL IS REQUIRED TO FLY BETWEEN FL290 AND FL410
INCLUSIVE.
5. EIGHTY PERCENT OF GROSS NAVIGATION ERRORS RESULT FROM POOR COCKPIT
PROCEDURES. ALWAYS CARRY OUT PROPER WAY POINT CHECKS.
END OF PART TWO OF TWO PARTS)



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