B-2 gps navigation problems, B-3 fuel consumption problems – NorthStar Navigation EXPLORER 657 User Manual

Page 87

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87

Northstar Explorer 657 Installation and Operation Manual

B-2 GPS navigation problems

2-1 No GPS fix or long time to get fix at

startup:

a

May occur occasionally if the antenna does
not have a clear view of the sky. The satellite
positions are constantly changing.

b Antenna cable not connected to display unit.

2-2 657 GPS position different from true

position by more than 10 m (33 ft):

a

657 in simulate mode. Turn simulate mode off
(see section 17-15).

b The normal error in GPS position will exceed

10 m (33 ft) for about 5% of the time.

c

Under special circumstances the US
Department of Defence may introduce a
deliberate and changing error in the GPS
positions of up to 300 m (1000 ft).

2-3 657 position different from same

position on local charts:

a

657 in simulate mode. Turn simulate mode off
(see section 17-15).

b Incorrect chart datum. Select the correct

chart datum (see section 17-2).

c

Map shift has been applied wrongly. Clear
map shift, then reapply if necessary (see
section 17-2).

2-4 Can not see boat on chart:

Press

to switch to center on boat

mode (see section 3-2-1).

2-5 The time or date on satellite window is

wrong or off:

a No

GPS

fix.

b In simulate mode. Turn simulate mode off

(see section 17-15).

c

Local time offset is wrong (see section 17-13).
The Local Time Offset must be changed
when daylight saving time starts or ends.

2-6 Autopilot not responding to 657; no

NMEA output:

a

NMEA output disabled or the required NMEA
sentences are not turned on. Check NMEA
settings (see section 17-10).

b Check that the instrument is connected

correctly.

2-7 No DGPS fix or loss of DGPS fix:

a

To receive a DGPS fix, WAAS/EGNOS must be
enabled or an optional DGPS antenna fitted
(see section 7).

b With WAAS/EGNOS: Boat out of coverage

area (see section 7).

c

With WAAS: GPS antenna does not have a
clear view of the horizon towards the equator.

b With beacon DGPS: boat out of range of a

DGPS beacon.

3-1 Fuel used or remaining seem inaccurate:

a

657 is not wired for auto power (see section
18-4).

b In rough seas, fuel may surge back and forth

through the fuel transducer, resulting in
incorrect readings. Try installing a one-way
valve between the fuel transducer and the
fuel tank.

c The

Set remaining fuel value must be

reset after every refuelling (see section 12-1).

d The fuel tank may not refill to the same

capacity each time due to air pockets.

B-3 Fuel consumption problems

This is particularly noticable with underfloor
tanks.

e

Fuel transducers wear out over time and
should be replaced after every 5000 litres of
fuel.

3-2 Flow indicates no fuel or low fuel:

a

Check that the number of engines is set to 1
(see section 17-5).

b Check that the fuel cable connectors are

securely plugged in and the collar is locked
in place. The collar must be locked in place to
give a watertight connection.

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