14) A static wristband should be worn when dealing with instruments as even when the aircraft is switched off, some charged electricity is produced and the static wristbands act as an earth to prevent harm on the personnel.
15) A replaced instrument should have the right code number as the old one.
16) While removing the instrument, it should be carefully handled to avoid damage occurring onto it and make sure that all the wires are disconnected first.
17) Overhead instruments should be carefully handled to avoid them falling on you head as they are placed on top.
18) When removing some instruments, the wire is still connected from behind so after removing this wire, it should be clamped to avoid it being pulled back into the main frame. In other words, some wires are like a seat belt in a car, when you pull then leave, it pulls back.
19) A special radioactive tag should be worn when dealing with signals and nuclear environments. This tag reads how many rays the body took during the time of work.
20) Last but not least, be clever! Think before touching. Your brain is in your head not hand, remember?!
Section 3:
For this section, I decided to mix part a and b together. The test will be specified then its results. I decided to go with the airspeed indicator test as explained in class by Malcolm Ross. Lets take the Jet Stream 31 for an example. The airspeed is determined by the flow of the air into the pitto available on the left front side of the Jet Stream 31. It has a centrifugal shaped hole in the front to allow air to enter through it. To test the airspeed indicator, we must first follow the safety precautions mentioned in number 11 in section 2. Then a pressure pump must be provided. Make sure you attack the signs that working on the pitto is in progress then plug the tube onto the pitto opening and make sure it is tight with no air leakage. Switch on the air speed indicator and apply pressure. Make sure you take a good look on the pressure meter on the pressure pump and record the data. At the same pressure supplied make sure you record the data displayed by the airspeed indicator now. Repeat the process on different pressure supplies then compare both records (the pressure meter and the air speed indicator). If they are identical, the system is working fine with no faults. An important note is that some airspeed indicators can reach a certain limit so keep the pressure supply within the limit. If a minor difference is there then make sure the indicator is set at the right beginning point before starting as the pointer may change over time.
If the records are totally different, check the instrument itself and repeat process. There may be a fault in the pins or attachment or wiring order. After checking the instrument and repeating the process, if it matches, the green light is on and the test is successful, if a difference is still there, replace the indicator. Check again, is the records matches, and then the test is successful. If the fault is still there, check the pitto now and replace it, as it is the last possible fault. The test should be successful then.
Make sure the pressure meter on the pressure pump and the pump itself are functioning properly as the fault can be from them.
Another test for assuring distinction criteria. The ILS (Instrument Landing System) Test. The system checkout is made on a selected frequency for which no ILS signal is received.
Selected course: zero
Set Test Selector in UP/L
After 6 seconds approximately check that on the HSI:
The G/S flag goes of view
The Glide slope marker deviated upwards
The NAV flag goes out of view
On the ADI:
The LOC flag goes out of view
The G/S flag goes out of view
The Glide slope index deviates upwards
The LOC index deviates leftwards
Command bars deviate UP/LEFT indication
Then set the test button DN/R. The same operation occur but in the reverse direction.
Conclusion:
In conclusion, three sections were covered in this assignment; the first section talks about two instruments in depth, their mechanism and operation. The first section also includes the reason for monitoring aircraft systems. Section 2 is all about the health and safety procedures that should be followed and includes the basic common precautions along with the more sophisticated in depth safety precautions that should be followed while handling aircraft instruments. Finally, the last section was mixed together to show the test then its results and it explained how to test the airspeed indicator and took the Jet Stream 31 as an example. Following those sections, the reader should have a clear understanding on the altimeter and the vertical speed indicator as well as the safety precautions for handling aircraft instruments and finally how to test an airspeed indicator and what results should we expect.
Written by Odali
