Boeing B737 Study Material

1. LVO CAT I/II/III OPERATIONS
Jakub Muransky

2. LESSON CONTENT
 INTRODUCTION
 GENERAL CONCEPT CAT II/III
 LVTO
 FLIGHT CREW PROCEDURES
 AIRFIELD REQUIREMENTS
 OPERATIONAL REQUIREMENTS

3. INTRODUCTION
 CAT II / CAT III provides a level of
safety when landing in low visibility
conditions, equivalent to that of
'normal' operating conditions
 Category II / Category III constitutes
the main part of All Weather
Operations (AWO), which also consists
of Category I, take-off, and taxiing in
low visibility conditions
 Moreover, approach success rate in
actual in-line services is now nearly
100%

4. INTRODUCTION
 Although ICAO, the FAA and EASA regulations are
slightly different, all refer to the same concepts for CAT
II/CAT III operations
 CATII provides sufficient visual reference to permit a
manual landing at DH
 CATIII does not provide sufficient visual references and
requires an automatic landing system

5. INTRODUCTION
 In Category III, pilots see the runway lights only few seconds (about
5 seconds) before touchdown

6. MAIN OBJECTIVES
 To maintain required level of safety AWO concept must
fulfill:
 the aircraft
 the airfield
 the flight crew
 the operator

7. DECISION HEIGHT VS RVR
 All definitions refer to the concept of Decision Height
(DH) and Runway Visual Range (RVR)
 It is worth noting the difference between Cat II definitions
by ICAO and FAA, and the definition by EASA of the
minimum runway visual range

8. DECISION HEIGHT
 Is the wheel height above the runway elevation by which
a go-around must be initiated unless adequate visual
reference has been established or
 The aircraft position and approach path have been
assessed as satisfactory to continue the approach and
landing in safety (EASA)

9. DECISION HEIGHT
 In Category II operations, DH is always limited to 100ft or Obstacle
Clearance Height (OCH) whichever is higher
 In Category III operations with DH, the DH is lower than 100ft
 When necessary, the published DH takes into account the terrain
profile before runway threshold

10. ALERT HEIGHT
 Is a height above the runway, based on the
characteristics of the aeroplane and its fail-operational
automatic landing system, above which a Category III
approach would be discontinued and a missed approach
initiated if a failure occurred in one of the redundant parts
of the automatic landing system, or in the relevant ground
equipment (ICAO)
 Alert Height is connected with LAND2, LAND3 or NO
AUTOLAND annunciation

11. ALERT HEIGHT
 Fail-operational automatic landing system - if in
the event of a failure, the approach, flare and landing
can be completed by the remaining part of the
automatic system
 Fail-passive automatic landing system - in the
event of a failure there is no significant deviation of
aeroplane trim, flight path or altitude but the landing
will not be completed automatically

13. ALERT HEIGHT
 Go-around above Alert Height for failures affecting
fail operational system
 Below Alert Height continue except for Autoland
warning
 Height evaluated during certification - typically 100 -
200feet (200 - B737)
 Operators can select lower Alert Height

14. RUNWAY VISUAL RANGE
 Range over which a pilot of an aircraft on the centreline
of the runway can see the runway surface markings or
the lights delineating the runway or identifying its
centreline
 Transmissometers strategically located
 Three basic portions of runway - the touchdown zone
(TDZ), the mid-runway portion (MID) and stop end

15. RUNWAY VISUAL RANGE
 RVR reports
 Reports are given with 50 m increments if RVR is less
than 800 m
 25 m increments if RVR drops below 150 m
 No need to give MID and END value by ATC if they are
higher or equal than TDZ
 ATC must have an update of RVR every 15s available

16. RUNWAY VISUAL RANGE

17. RUNWAY VISUAL RANGE
 Minimum visual segments at DH have been
established for each category
 Typical values are 200m for CAT IIIA and 300m for
CAT II automatic landing

18. RUNWAY VISUAL RANGE
 A too-low seat adjustment may greatly reduce the visual
segment
 When the eye reference position is lower than intended,
the already short visual segment is further reduced by the
cut-off angle of the glareshield or nose

19. VISUAL SEGMENT AT DH=100ft
WITH RVR 300m (TYPICAL CAT II)

20. VISUAL SEGMENT AT DH=50ft
WITH RVR 200m (TYPICAL CAT III A)

21. RVR MINIMA
 Pilots require 1-3 seconds to establish visual contact
 To establish lateral position pilots required to see not less than three
lights
 Establish an RVR to to be associated with that DH to ensure required
visual reference is established
 Eye position is important

22. MINIMUM APPROACH BREAK-OFF
HEIGHT
 Is the lowest height above ground measured by radio-
altimeter such that if a missed approach is initiated
without external references
 Replaced by minimum DH or indication in AFM of altitude
loss during automatic go around - either MABH or altitude
loss in AFM can be use to determine minimum DH in CAT
III operation

23. MINIMUM APPROACH BREAK-OFF
HEIGHT
 REFERENCE LOST below DH = immediate go around
 a) by pressing TO/GA above 20 ft aircraft stays airborne
 b) by pressing TO/GA below 20 ft aircraft will make go
around contact by main landing gear – TO/GA feature
available
 c) by pressing TO/GA below 20 ft aircraft will make
ground contact by all wheels – TO/GA feature inhibited,
roll out must be completed

24. OPERATING MINIMA
 Minima are generally expressed
by RVR and DH
 There is direct corellation
between both of them
 DH vs RVR can be influenced
either by:
 a) approach lighting system
capability
 b) or close in obstacles

25. OPERATING MINIMA

26. OPERATING MINIMA
 An operator is responsible to establish its minima which
cannot be lower than:
 Airfield operating minima - OCA (H)
 System minimum
 Minimum stated by state authority
 Aircraft minima stated in AFM
 Crew minima
 AXE uses minima provided by LIDO up to CAT II but own
minima for CAT IIIA to fulfill missed approach gradient

27. OPERATING MINIMA

28. GENERAL CONCEPT
CAT II

29. GENERAL CONCEPT
CAT II
 CAT II weather minima has been established to provide
sufficient visual references at DH to permit a manual
landing (or a missed approach) to be executed (it does
not mean that the landing must be made manually).
 More restrictive RVR can be imposed by the procedure in
case of CATII manual landing

30. GENERAL CONCEPT
CAT II
 ICAO definition
 DH lower than 200ft but not less than100ft
 RVR not less than 350m
 EASA definition
 DH lower than 200ft but not lower than 100ft
 RVR not less than 300m

31. GENERAL CONCEPT
CAT II
 As it is sometimes necessary to increase DH (close in
obstacles), the RVR minima according to EASA and FAA
are a function of the DH
B737 DH RVR
CAT II
100-120 300
121-140 400
141-199 450

32. GENERAL CONCEPT
CAT II
TDZ MID END
APP CHART 125m 75m
As per AXE other measured parts of RWY must fulfill following RVR minima:
END RVR required if speed at this part is more than 60 kts

33. GENERAL CONCEPT
CAT III
 A CAT III operation is a precision approach at lower than
CAT II minima
 CAT III weather minima do not provide sufficient visual
references to allow a manual landing
 Pilot decides if the aircraft will land in the touchdown
zone (basically CAT III A) and to ensure safety during
rollout (basically CAT III B)
 Automatic landing system is mandatory to perform
Category III operations

34. GENERAL CONCEPT
CAT III
 CAT Ill has three sub-categories:
 CAT III A
 CAT III B
 CAT III C

35. GENERAL CONCEPT
CAT III
 Automatic landing is not CAT III and is not related to
particular weather conditions
 This system is mandatory for all CAT III operations
 Perform automatic landing in good visibility but ILS
performance must be sufficient and ILS signals protected

36. GENERAL CONCEPT
CAT IIIA

37. GENERAL CONCEPT
CAT IIIA
 ICAO and FAA definition
 No decision height or a decision height lower than 100ft
and a runway visual range not less than 200m
 EASA definition
 DH lower than 100ft and a runway visual range not less
than 200m

38. GENERAL CONCEPT
CAT IIIA
TDZ MID END
APP CHART 125m 75m
As per AXE other measured parts of RWY must fulfill following RVR minima:
END RVR required if speed at this part is more than 60 kts

39. GENERAL CONCEPT
CAT IIIB
 ICAO and FAA definition
 No decision height or a decision height lower than 50ft
and a runway visual range less than 200m but not less
than 50m
 EASA definition
 No decision height or a decision height lower than 50ft
and a runway visual range less than 200m but not less
than 75m

40. GENERAL CONCEPT
CAT IIIC
 ICAO and FAA definition
 No decision height and no runway visual range limitation
 CAT III C operations are not currently authorized and the
EASA does not mention this sub-category

41. CAT II/III SUMMARY
EASA

42. CAT II/IIIA AXE WIND LIMITATION
Wind component Wind velocity
Headwind 25
Crosswind 20
Tailwind 10
B737 AFM limitations

43. AUTOMATIC LANDING CAT II/IIIA
 Mandatory equipment:
 Dual channel A/P
 Low range radio altimeter and display
 DH light or display
 Two ADIRU (IRU in NAV mode)
 Windshield rain removal system
 FMA for each pilot
 ILS receiver and display for both pilots
 Two sources of electrical power

44. LOW VISIBILITY TAKE OFF
 Takeoff with RVR less than 400m is considered as LVTO
by EU OPS
 The Takeoff minima is mainly determined by the airport
installation (runway lighting system, RVR measurement
system, ...)

45. LOW VISIBILITY TAKE OFF
Facilities RVR
Night: w/o HIRL 700
Day: w/o HIRL 500
Day: runway edge lights and
runway centre line markings
Night: runway edge lights and
runway end lights or runway centre
line lights and runway end lights
300
Runway edge lights and runway
centre line lights 200
Runway edge lights and runway
centre line lights + multiple RVR
information
150
High intensity runway centre line
lights spaced 15m or lessand high
intensity edge lights spaced 60m or
less + multiple RVR information
125

46. LOW VISIBILITY TAKE OFF
 Take-off minima 125m RVR:
 LVO in force at the airport
 HIRL spaced 15m + high intensity edge lights spaced
60m or less
 Crew training undergone
 90m visual segment clearly visisble
 The required RVR has been achieved for all relevant
RVR reporting points

47. LOW VISIBILITY TAKE OFF
Wind component Wind velocity
Headwind 35
Crosswind 20
Tailwind 10
B737NG AFM wind limitation:

48. LOW VISIBILITY TAKE OFF
 Additional considerations
 Takeoff alternate is normally required within one hour for
twins
 Conditions - one engine inoperative speed in still air in
ISA conditions based on actual take-off speed
 Max. distance for B737-800 is 255NM
 Allowance for fail operational systems

49. LOW VISIBILITY TAKE OFF
INSTRUMENT SETTING
MCP course display (both) Runway heading of the active rwy
NAV1 ILS of the active RWY
NAV2 ILS of the active RWY
EHSI 1 EFIS mode in map mode
EHSI 2 EFIS mode in RAW DATA or
expanded RAW data
Instrument setting as per AXE SOPs:

50. FLIGHT CREW PROCEDURES
 If CATII/III approach has been conducted CAT II/IIIA
report must be filled
 All airports intended to be used for CAT IIIA approach
must be before verified by the approach to CAT IIIA
performed in conditions equal or better than CAT II
minima (EU-OPS, CAT)
 Status of an airports can be found and verified in List of
Adequate Airports in LIDO AXE manuals

51. FLIGHT CREW PROCEDURES

52. FLIGHT CREW PROCEDURES
 The pilot at the left pilot seat (PIC) is always the pilot
flying (PF)
 The pilot at the right pilot seat (FO) is always pilot
monitoring (PM)
 Take-off briefing is performed prior taxing

53. FLIGHT CREW PROCEDURES
 The PIC shall be PF if RVR or VIS drops below 800m
 Take-off is performed after stopping on the RWY
 Landing flaps extended to 40°
 Min. autobrake setting should be 3

54. FLIGHT PROCEDURES
 IN FLIGHT TASK SHARING:
 PF monitors the flight instruments and at 100ft above the
DH shifts his view otside to establish visual contact
 PM monitors the flight instruments and announce any
deviation
 PM monitors flight instruments through all flight down to
DH, landing until reaching taxi speed
 In addition performs following call-outs

55. FLIGHT PROCEDURES
CAT II
At DH = 100ft
GPWS voice MINIMUM
PF LANDING or GO AROUND
At 50ft
PM FLARE or NO FLARE
At 27ft
PM RETARD or NO RETARD

56. FLIGHT PROCEDURES
CAT IIIA
At DH = 50ft
GPWS voice MINIMUM
PM FLARE or NO FLARE
PF LANDING or GO AROUND
At 27ft
PM RETARD or NO RETARD

57. FLIGHT PROCEDURES
MCP course selector APP inbound course
NAV CPT ILS of RWY in use
NAV FO ILS of RWY in use
ND or EHSI CPT MAP mode
ND or EHSI FO APP mode
ADF 1 LOM
ADF 2 LMM or NDB behind the RWY

58. FLIGHT PROCEDURES
 Required visual reference:
 Approach lights (3 in sequence)
 Runway centre line lights (3 in sequence)
 TDZ lights
 RWY edge lights
 Or combination of all the above
 CAT II approach - lateral element of approach aids

59. FLIGHT PROCEDURES
 Go around – manual or automatic
 Automatic go around – 3 reasons:
 1. instructed by ATC
 2. no visual contact or contact lost below DH
 3. PF incapacitation

60. AUTOPILOT FAILURES
 Steady red A/P disengage warning light
 1. Below 800 ft during approach – stab out of trim –
disengage A/P manual go around
 2. During G/A – elevator position not suitable for single
channel operation – manual level-off or set higher MCP
altitude

61. AUTOPILOT FAILURES
 No FLARE annunciation – 500 ft RA during approach –
pitch and roll monitors may not be enabled or only first
A/P channel is engaged – disengage A/P manual go
around

62. AUTOPILOT FAILURES
 Flashing red A/T disengage light – A/T is disengaged –
continue approach retard thrust manually
 Flashing red AUTOLAND light – below 500 ft – A/P
disengages or stab trim warning occurs – disengage A/P
manual go around
 Flashing red AUTOLAND light – below 200 ft – ILS
deviation warning occurs – disengage A/P manual go
around

63. AIRFIELD REQUIREMENTS
The following subjects:
 runway characteristics
 visual aids
 non-Visual aids (ILS)
 RVR measurements
 obstacle clearance area
 ATC procedure,
 maintenance procedure

64. RUNWAY CHARACTERISTICS
 RUNWAY LENGTH
 There is no specific
requirement
 Only an operational limitation
 RUNWAY WIDTH
 Not less than 45m
 Touchdownzone beginning at
the threshold and extending to
a distance of 900m

65. RUNWAY CHARACTERISTICS
 RUNWAY SLOPE
 First and the last quarter of the length of the runway the
slope does not exceed 0.8%
 Slope maximum of 2% per 30m

66. RUNWAY CHARACTERISTICS
 OBJECTS ON RUNWAY
STRIPS
 No fixed object (other than
frangible visual aids) are
installed on a runway strip
within 60m of the
centerline
 The distance between the
holding position and the
centerline of the runway is
not less than 90m

67. VISUAL AIDS
 Runway centerline marks must have a width not less
than 0.90 m
 CAT II or CAT III signs placed on either edge of the
taxiway at the holding-position
 Sign CAT III must be accompanied with flashing lights.

68. VISUAL AIDS
 Runway lights for CAT II or
CAT III consist of:
 high intensity threshold lights
 runway end lights
 runway touchdown zone lights
 runway edge lights
 runway centerline lights

69. VISUAL AIDS-APPROACH LIGHT SYSTEM
 The ALS is mandatory for CAT II operations
 Optional for CAT III operations
 Row of lights on the extended centreline of the runway,
extending over a distance of 300m from the threshold
(over 900m for CAT I)
 System has two side rows of lights, extending 270m from
the threshold, and two crossbars, one at 150m and one
at 300m from the threshold

70. ILS FACILITY
 In CAT II and III approaches, the ILS beams must be
protected from unacceptable disturbance
 Two kinds of protection area are defined
 the critical area
 the sensitive area