hh - Himalaya Flashcards
Limitations observed on the Himalayan RTE
Until when should the diversion route and altitude restrictions be observed on the Northern Himalayan Route?
[NH DARD - Preamble - Escape Route Planning]
Until either:
- under radar control, or
- an instrument approach can be commenced, or
- the MTCA or MGA on the relevant chart allows a lower altitude to be flown, or
- visual avoidance of terrain is assured.
What’s the Terrain clearance on the Northern Himalayan Route?
[NH DARD - Preamble - Terrain Clearance]
North Himalayan terrain clearance considers discrete segments between two waypoints, within 10 NM either side of the flight path centerline and includes a 10 NM semi-circular buffer around the waypoints at each segment end.
The segments between GOT30 - DS125 and GEOFF - PURPA are analyzed up to a corridor width of 20 NM to the north west of the airway to achieve terrain clearance at FL260.
Within a segment the highest terrain contour is identified, and terrain within that contour is assumed to rise to the maximum of that contour level (e.g. 9,999 ft.). A buffer of 2,000 ft. is then applied (see the example below).
Example:
Contour interval = 1,000 ft.
Highest contour identified = 9,000 ft. Terrain assumed to rise to 9,999 ft.
Buffer of 2,000 ft. applied
Minimum step down altitude = 12,000 ft.
What’s the speed used to calculate the Depressurization Strategies?
[NH DARD - Preamble - Speed]
For depressurization, the analysis is done at MMO/VMO and the resultant descent profile is adjusted for the effect of statistical en-route wind
Do you have to apply cold temperature corrections on the Northern Himalayan Route?
[NH DARD - Preamble - Corrections]
In the event of depressurization, crew shall apply cold temperature corrections, as applicable.
[OMC 10.4.1.1 Enroute]
The following altitudes shall be corrected for cold temperature altimeter effects:
- Minimum Enroute Altitude (MEA),
- Minimum Holding Altitude (MH),
- Minimum Grid Altitude (MGA),
- Minimum Obstacle/Obstruction Altitude (MOCA),
- Minimum Terrain Clearance Altitude (MTCA).
- Minimum Safe Altitude (MSA).
For ISA -15°C to -29°C: add 10% to the Minimum Altitude.
For ISA -30°C or colder: add 20% to the Minimum Altitude.
What’s the limitation applicable for turns on the Northern Himalayan Route?
[NH DARD - Preamble - Turns]
If the aircraft goes outside the NH 10 NM envelope limit the descent to the grid MORA until aircraft is back on the escape route.
A380: Turns should be done in HDG mode and close to green dot speed in order to minimise turn radius. Upon turn completion, accelerate and sequence the F-PLN.
What’s the Minimum CABIN Oxygen Pressure At Dispatch for the Northern Himalayan Route, and for the other routes?
[FCOM/LIM/OXY]
A380 Without First Class:
- Routes for which Depressurization Strategies have been published in the OFP: 1350 PSI
- Routes in the ‘Driftdown and Rapid Depressurisation Strategies North Himalayan Region’ chart: 1750 PSI
A380 with First Class:
- Routes for which Depressurization Strategies have been published in the OFP: 1300 PSI
- Routes in the ‘Driftdown and Rapid Depressurisation Strategies North Himalayan Region’ chart: 1650 PSI
- Routes for which LIDO-OFP could not calculate Depressurization Strategies: Company NOTAMS on Depressurization Strategies for particular Company Route
Can you name some of the Built-in Protections on the Northern Himalayan Route?
[DARD Video]
- Terrain clearance is based on Net Flight path (instead of Gross);
- Altitude buffer of 2000 ft entirely (instead of 2000 and 1000 ft);
- Net Flight Path calculated with MZFW Dispatch;
Net Flight Path calculated with Wing & Engine A/ICE on.
Do you need to apply QNH corrections on the Northern Himalayan Route?
[DARD Video]
No.
All additional Built-in Protections provide enough safe margin.
When descending according to the DARD escape route, a level off at FL220 is expected, however due cold temperature correction, level 220 becomes 240. Is this a case of altitude bust?
[DARD Video]
No.
The geometric altitude will still be 22000 ft.
