Topics in Category: GIV - Rotate.Aero Wed, 23 Jan 2019 00:35:31 +0000 MYOB /media/kunena/images/icons/rss.png Topics in Category: GIV - Rotate.Aero en-gb ATA 30-22, Nose Cowl Anti-Ice - by: Mark

Sense lines fed from a set of "T" fittings downstream from the valve provide bleed air pressure to the transmitter and switch.

Another line is back-fed into the valve as a reference for pressure regulation.

This particular aircraft had a problem with right engine A/I pressure indication in the cockpit. It showed "00" with the system turned on. The crew noted that there was a minor increase in turbine TGT of 10C with the anti-ice commanded on.

The output signal from the pressure transmitter ranges from 0-5 VDC depending on the actual pressure. To rule out a indicator problem, this output can be simulated with some batteries (or DC power supply).

With 1.5 volts from a single "D" cell battery placed on pins "A" (negative or common) and "B" (signal or positive) of the transmitter plug, a indication of 36 PSI was observed.

Per a crew verbal, normal TGT rise is around 40C when cowl anti-ice is switched on.
A replacement valve was placed order. The assumption was that it was opening, but not to the extent needed to provide the correct indication and actual anti-ice air. The sense lines were planned to be checked for blockage at the time of the valve change.

AMM 30-02-00
WDM 30-22-00
ATA 30 Ice/Rain Protection Fri, 15 Dec 2017 22:38:58 +0000
ATA 24-03, EPMP - by: Mark
The cockpit overhead panel needs to dropped down. On GIV's, both of the L/H-R/H overhead circuit breakers panel covers need to come off.

One pain-in-the-ass aspect of an EPMP change is the fact that the inboard panel mounting screws (3 ea) are covered by the adjacent fuel system light-plate. That plate must come off which would seem simple, but...... the two guarded switches (APU Fire Bottle and Fuel Intertank) have to slide out with the light-plate as the plate itself will not clear the plastic/metal of the guard.

The center and left aft cockpit headliner panels need to be removed of pushed aside to gain-access-to (my favorite words in aviation) the panel disconnect plugs (4ea, 2 left, 2 right) mounted on the frame rib. Gulfstream didn't exactly provide a ton of room between the plugs, so using any type of cannon plug pliers for plug removal is impossible.

The odd numbered plugs (1 and 3) are mounted aircraft left.

The even numbered plugs, aircraft right. And yes....... the add-on black plug and relay "do" get in the way.

Plug harness's all disconnected and hanging down.

EPMP viewed with overhead hanging down.

GIV AMM 24-03-02]]>
ATA 24 Electrical Power Sun, 09 Oct 2016 00:14:57 +0000
Bleed Isolation Valve Indication - by: Mark

Relay K61A in lower left relay panel, second rack back.

Iso valve in hell-hole. Dead center top above ladder landing platform.

#1 DAU. Left radio rack.

The problem turned out to be a bad relay. A short vid showing what it was doing can be found here .

GIV ATA 36, Pneumatics
Isolation Valve Indication
AMM 32-00-00 and 36-12-00
WDM 36-12-00
ATA 36 Pneumatics Fri, 17 Apr 2015 00:55:52 +0000
ATA 35-10, GIV Crew Oxygen - by: Mark

Had hydro certification done on bottle #4 (crew bottle, location aft right), but made the mistake of pulling #2 (passenger bottle, fwd right) first.
Noticed when larger brass line was loosened on the #2, a continual bleed occurred. Two Gulfstream mechanics were onsite and they mentioned that the paired bottle's fitting also needed to be removed. When it was..... all bleed-off stopped.

I learned that these two line are tied together with a "T" fitting. They hook to a bottle fitting with an internal Schrader valve. It is not until the brass line has been backed off that the valve shuts. This valve "is not" controlled by the bottle shutoff. Great........ I learned something. (One final note: The bottle pressures equalized with each other when the large brass lines were installed.)

I pulled #4, but when I disconnected the same position brass fitting..... no air????? When the bottle was returned, I hooked everything up. I had no pressure indication in the cockpit or fill point. I had plenty of flow to the masks. WTF?????

Upon pulling the brass fitting on #3, it was found not seated. My initial seat on #4 was bad also. Both were corrected.

In this case, before anything was dicked with, the crew pressure indication was only the #4 bottle, but mask flow was present for both.

I did a hand drawing of what "should be" the correct bottle output fittings. Please correct me if this is wrong.

ATA 35 Oxygen Thu, 05 Mar 2015 00:58:02 +0000
ATA 33-10, GIV Pilot's Console Flood - by: Mark

$700 for a bulb that didn't fix the problem of no console light.

The inverter is located outboard of the Captain's left rudder peddle (right peddle for F/O's). And yes........ the seat has gota come out.
Two power pins on A and C, which read 28VDC.
D and E are for the control potentiometer. 48.1K ohms full CCW, 1.2 ohms full CW.
Pin F is ground.

Replacement inverter corrected problem.

GIV ATA 33-10-00
WDM 33-12-00
IPC 33-10-00 Figure 1
ATA 33 Lights Wed, 04 Mar 2015 01:56:42 +0000
ATA 24-30, GIV EPMP Battery Switch - by: Mark
The EPMP panel is quite expensive and there seems to be no breakout for individual switch replacement. Positive verification of failure is always appreciated by operators before all that cash is laid out.

It was somewhat perplexing that with the EPMP panel switch pushed in (and no power) that when either outside was switched on then off.... power remained on the aircraft???? I could find no "backdoor" for contactor power.

View with panel behind seat removed.

Relay K2 is on most inboard relay rack.

The terminal strip was actually the second strip going outboard.

GIV ATA 24-30-00
Maintenance Manual 24-02-00
Wiring Manual 24-30-00
ATA 24 Electrical Power Mon, 01 Dec 2014 02:17:49 +0000