Our pilot manuals seem to be silent on the subject of "unscheduled maintenance." But you need to keep in mind there are times when you need to get a mechanic when you weren't planning to:
We seem to know when something we did, something someone did to us, or just something in general will require an airplane inspection. But some of these you may not know about. Have you ever told ATC you just rode through severe turbulence? Well now you must get the airplane inspected. And there are more things just like that.
The following is not presented as a "how to" for mechanics, but as a primer for pilots to understand the scope of the needed inspection. Read on . . .
Everything here is from the references shown below, with a few comments in an alternate color.
Photo: Bird on Salisbury Beach, MA, (Eddie Photo)
[G450 MM, §05-50-00, ¶18]
Photo: G450 Interior, (Eddie Photo)
[G450 MM, §05-50-00, ¶13]
The "Bruce Industries" cabin lights are basically all of the fluorescent bulbs. If any component fails, an involved inspection is required that looks for evidence of overheating, improper connector locking, missing components, electrical arcing or carbonization. You can, alternatively, deactivate and placard the system as INOP.
Photo: G450 TROV and PRV, (Eddie Photo)
[G450 MM, §05-50-00 ¶12]
This is a rather involved procedure, you shouldn't pawn this off to a generic A&P mechanic. You will need a Gulfstream expert.
Photo: G450 Flaps and Stab
[G450 MM, §05-50-00, ¶5]
This procedure requires everything in the system be checked for scoring, gouges, wrinkles, looseness, cracks, distortion, missing components or other signs of damage. That includes each flap track, rollers, assemblies, gearbox, torque shafts, pillow blocks, wing rear beam, jackscrew actuators and actuator housing.
Photo: Fire bottles
[G450 MM, §05-50-00, ¶16]
If the fire bottle is discharged for any reason, it has to be replaced and the shuttle valve that connects it to the engines must be inspected.
Photo: Hail damage
[G450 MM, §05-50-00, ¶ 3]
This inspection is pretty much what you would expect, a visual check of just about everything for distorted or dimpled panels, delamination, cracks, or broken parts.
Photo: G450 Main landing gear prior to landing, (Eddie Photo)
[G450 MM, §05-50-00, ¶7]
This is a fairly long and evolved inspection. It begins thusly:
Some of the questions will be for the pilot. What it a two-point or three-point landing. Were there side loads applied to the main landing gear? What was the ground speed at touchdown?
The aircraft will need to be jacked and much more than the landing gear will have to be inspected. The cabin windows and baggage door, for example, must be examined for wrinkles, buckling, and popped rivets. The MAU will record vertical and lateral loads and the maintenance manual presents acceptable loads versus weight. (Anything less than 1.7G is generally okay at all weights. At lower weights the graph goes up to 2.3 G.
Photo: Gust lock handle, (Eddie Photo)
[G450 MM, §05-50-00, ¶11]
This inspection requires access to several of the lock mounting brackets, crank assemblies, latch hooks, and other components. Of special note, one of the floorboards and the cockpit pedal panel access panels have to be removed. This is not a quick check.
Photo: Cloud-to-cloud lightning
[G450 MM, §05-50-00, ¶2]
Mechanics will need to know the following: Did you observe the strike and if so, where was it? Was the landing gear extended? What about the flaps? What about the spoilers?
The check is, for the most part, a visual inspection of the airplane. If a strike on the engines is suspected, the engine check can be a bit more involved.
Photo: G450 nose wheel overtravel indicator, (Eddie Photo)
[G450 MM, §05-50-00, ¶8]
This inspection involves removing the steering collar assembly covers, removing and checking the shear pin for damage, and reinstalling everything if no damage is found. The pop-up indicator is reset by inserting a thin rod into an access hole while pushing the pin down.
Photo: Pretakeoff contamination check, (Eddie Photo)
[G450 MM, §05-50-00, ¶17]
The inspection involves moving the flaps full down and rotating the aileron trim full right before removing several access panels and conducting a visual inspection of aileron, elevator, and stabilizer areas.
Photo: G550 N535GA, (NTSB Photo)
[G450 MM, §05-50-00, ¶10]
This inspection requires the wheels and tires be removed, inspected, and replaced if necessary. Brakes, landing gear, and all surrounding areas are also inspected.
Photo: Turbulence advisories
[G450 MM, §05-50-00, ¶4]
This is a long and involved inspection that requires floorboards and other access panels be removed. You shouldn't expect a quick "once over," this will take a day, at least.
Photo: Excessive tire wear, (Goodyear tire manual)
[G450 MM, §05-50-00, ¶15] Replace tire if any of the following defects exist:
The inspection call for looking for evidence of any foreign objects.
Photo: Tire abuse
[G450 MM, §05-50-00, ¶9]
This inspection is quite a bit more involved than the previous check. It requires a check of all components, hydraulic lines, electrical harnesses, the structure, the skin, and basically anything that could have been damaged by flying tire debris.
Photo: G450 powerplant, (FSI MTM, figure 7-1)
[G450 MM, §05-50-00, ¶1]
This inspection depends on what you suspect and the procedure farms out to other sections of the maintenance manual. Categories include: surge, ingestion of volcanic ash, bird strike or slush ingestion, shock loading, snow and ice before starting, high vibration, lightning strike, and bypass duct blockage.
Photo: Alaska volcano
[G450 MM, §05-50-00, ¶6] Volcanic ash particles are usually less than 5 microns and very abrasive. Ash can penetrate all orifices and cause erosion or etching on the surface. Ash particles can accumulate on all lubricated surfaces, in all corners and can cause contamination of all system filters. It is not possible to determine the level of damage volcanic ash contamination can cause. Therefore a full aircraft inspection is necessary to determine the extent of contamination.
This is a very long and detailed inspection, but it may not be long enough! Volcanic ash can get into everything and the damage can be more extensive than you might first think.
More about this: Volcanic Ash.
Gulfstream G450 Maintenance Manual, Revision 18, Dec 12, 2013
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