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AircraftTroubleshooting

So you want to help manage paperwork in a typical part 91 maintenance shop.

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Log entries should be brief such that a typical mechanic could understand the scope of work.

 

Airframe and Powerplant mechanic.

The A AND P mechanic is allowed to supervise any action he is ALLOWED to perform.  The log entry MUST include the name of the person who PERFORMED the work, and the name of the SUPERVISING mechanic.

In the real world, this ONLY  occurs on the CAMP cards with 2 signature lines.

Sign-off for repair on part91 airplane.

……….has specific wording

Signoff for inspection on part 91 airplane

……….has specific wording

ONLY a 145 REPAIR STAION can  build , retain , and  reference a WORK ORDER . A MECHANIC therefore must include any support document in EVERY LOG ENTRY.  In the real world, mechanics use brief log entries, and  seperate “work packages”,  or some such.

A few traps for young players:

1. The owner of the aircraft is responsible for the AIRWORTHYNESS of the airplane. Not the mechanic. This responsibility cannot be delegated under part 91.

However, in the real world it IS frequently delegated to the mechanic.

The mechanic ONLY approves the airplane to return to service.  The PILOT actually returns it to service.

In the real world, many pilots will not even walk around te airplane.

2.  The mechanic is responsible for WHAT HE DOES.  He is responsible to SIGN for what he does.

3. If a mechanic is contracted to do an inspection, he is required to sign the inspection AIRWORTHY or UNAIRWORTHY. In the logbook.

You can’t just stop an inspection, and push the airplane out.  An unairworthy finding must be accompanied by a letter with a list of discrepancies delivered to the owner……… Not a detailed log entry.

 

4. Parts must come from somewhere . Form 8130, or yellow tag, or  new stock from a vendor with a cofc. Or Vendor Work order number. Or REMOVED SERVICABLE  part with the proper declaration……   somewhere. Minor hardware may or may not be an exception to this rule

 

5. Something must ALLOW a mechanic to put a part on an airplane. AMM IPC reference, PMA with STC AML that lists the airplane model, or STC drawing that lists a PN, or AC43.13-1B standard pratices , or mechanics declaration that it is general practice…..Something.

6. If you are paid to do a repair, do the repair.  You are not required, or paid , to fix incidental descrepancies.  You are not doing an inspection.

In the real world we try to make everything we touch “right”

7.  Pistons track HOURS.  Jets track HOURS and CYCLES.

8. A TWELVE MONTH inspection is valid to the last day of the twelfth month. Plus a certain OVERFLY……..sometimes 1 month.  A 120 DAYS inspection is due midnight on the 120th day. In the real world, these dates are fungeable based on the part 91  owners proclivities.

9. Batteries and bottles require special date tracking, even more strict. They are tracked even more tightly than the airframe inspection.

10. AD sign-off MUST include AD NUMBER. DATE OF COMPLIANCE, , COMPLIANCE METHOD, RESULT, and NEXT DUE.

11. ENGINE MAINTENANCE entries belong in ENGINE LOG BOOKS.  same for airframe. Never the twain shall meet.

12. A part removed, and another part installed is not a REPAIR. It is not DAMAGE.  In the real world , this gets so stretched out that DAMAGE HISTORY is difficult to figure out.

13. Do not describe troubleshooting in the log entry.  Sometimes,, it makes sense to describe ACCESS.

14. Any discrepancy on a WORK ORDER must be closed.  In some way.  Othwise, the pilot is at risk of flying the airplane in a CONDITION OF INDETERMINATE AIRWORTHYNESS. Thats on the pilot.

 

15.

AircraftTroubleshooting

Full Rig on G100 slats

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The following is a description of Best Shop Pracices for a full Flap Slat Rig on a Astra, G100, and G150.  At no point should this information supplant OEM work card information.

Download and print the Gulfstream work cards:
1. Slat Rigg…
2. Flap Rig….
3. ……

The current work flow on the Slat Rig ….is difficult to follow, and omits the important mechanical length check on the bench.

The following information also references the older grey handbook entitled “Astra…….”

RAC all surfaces to extend.

Follow Gulfstream instructions to remove slats, flaps, and fixed LE covers. Remove 1 end of each drive cable from each jackscrew and PDU.

remove the jackscrews for Bench check length measurement. See Appendex 1.

Reinstall jackscrews

Check overrotation angles, see Appendex 2: Set #3 MECHANICAL UP DOGSTOP ….

Support lollypos with rods extended to the floor.

Rack all actuators to retract.

Lube all cables if applicable.

Do not connect drive cables to PDU. DO NOT RUN THE SLATS with the leading edge covers removed!, the trailing edge of the slat can hook the upper wing surface and damage WILL occur.

Remove actuators, measure on bench, at retract position. Adjust lollypop.

Install actuators

Set outboard actuators to retract dog stop voltage. turn lollypos to full retract  dog stop position. Vertical within 5 degrees? if not, cut safety wire and adjust lollypos to vertical.  Safety wire.

Measure actuator retracted length again.

if within specs, support reinstall and support  jackscrews.

Remove C1 to allow brake release.

Brake release. 9 1/2 turns out for slats by speed handle. 24 out for flaps.  !!!!!!! turn brake release off!!!!!!!!!!

Verify PDU is DISCONNECTED from inboard drive cables.

Connect C1

RAC PDU down a little, then up tp UP ELECTRICAL stop.

 

Connect inboard cables to PDU.

 

Be sure the Jackscrews are supported, and CANNOT touch the wing internal fuel cups.

RAC to full extend. this should drive all 6 actuators to full extend, just short of the dog stops.

Test degrees of over-rotation that is allowed to get to the dog stop.  the inboards should be 45(?) degrees from dog-stop.Appendex 1
middle should be 60(?) degrees from dog-stop
outboards should be 135(?) from dog-stop.

!!!!!IF!!!!! you have previously DOUBLE CHECKED the #3 jackscrew bench retract length, you can cut the safety wire and adjust the Lollypop to correct over-rotation angle.

The # 1 and #2 Jackscrew input drives can be twisted easily to obtain the EXACT over-rotation angle.

This is an opportune time to temporarily install the SLATS and check the slip fit of the 3 bolts. DO NOT RUN THE SLATS with the leading edge covers removed! The trailing edge of the slat can hook the upper wing surface and damage WILL occur. Remove the slats again.

Install fixed LE. Install Flap/Slat. If ANY one of the 3 jackscrew bolts is 1/2 hole off or worse: STOP WHAT YOU ARE DOING!  You have missed something.

If the 3 bolts holes are slip fit, move forward. If you can flex the slat a MINOR amount, say 1/8 inch, and install the bolts,you can move forward.

DO NOT RUN THE SLATS with the leading edge covers removed!, the trailing edge of the slat can hook the upper wing surface and damage WILL occur.

One last check for tools clear, LE Panels installed, NOT ONE SINGLE SCREW RAISED ABOVE THE SURFACE!!!!!, All hardware installed on the slat mechanism. PDU Drive shafts connected, Obstructions clear from movement areas.

RAC to retract. recheck retract RAW RETRACT voltage. if these are .050 out or more….STOP WHAT YOU ARE DOING, you have missed something.  Moving forward will result in a MIS-RIGGED airplane with excessive trimming on the electrical pots.  Leading to future problems.

Check Conditioned retract voltage. Adjust the 10 turn pots on FSECU face to book value.

RAC to extend.  Check conditioned extend voltage.

Check intermediate voltages, and flap angles.

 

Appendex 1: Bench Check the length of each actuator:

 

Appendex 2: Set #3 MECHANICAL AND ELECTRICAL UP DOGSTOP position , Adjust #1, and #2 UP DOGSTOP position

 

Appendex 3: Set 9 1/2 turns on slat, 24 turns on flap: