Engineering
Specification
Title:
Vertical
Speed
Indicator,
Ground
Support
Equipment
Barfield,
Inc
4101
NW
29
Street
Miami
Florida
33142
Drawing
No:
23
‐
337
‐
00025
Page
2
of
4
1. Purpose:
To specify performance requirements for pressure actuated vertical speed indicators for use
in B.I.C. manufactured ground support test equipment.
2. Scope:
This engineering specification covers four (4) basic types of direct indicating instruments as
follows:
TYPE I
- Range 0-2000 feet per minute climb and descent.
TYPE II - Range 0-3000 feet per minute climb and descent.
TYPE III - Range 0-4000 feet per minute climb and descent.
TYPE IV - Range 0-6000 feet per minute climb and descent.
3. Identification:
All units regardless of origin of manufacture are to be identified by B.I.C. assigned part
numbers as follows:
TYPE I
- to be identified as part number 337-00001.
TYPE II - to be identified as part number 337-00002.
TYPE III - to be identified as part number 337-00003.
TYPE IV - to be identified as part number 337-00004.
4. Test
Conditions:
Unless otherwise specified, all tests shall be made with the instrument mounted in the
horizontal (Face UP) position.
5. Performance
Requirements:
All units are required to meet the following performance requirements before installation in
any ground support test equipment.
5.1
Zero
Setting
Range:
The range of movement of the pointer by means of the zero adjustment shall not be
less than 400 feet per minute for the "UP" and "DOWN" position.
5.2
Scale
Error:
When subjected to the rates of changes of pressure indicated in Table 1 for the
altitude intervals shown, the errors shall not exceed the tolerances specified.
5.3
Lag:
The natural lag of the instrument when timed between the following points shall be
between 3 and 15 seconds:
TYPE I and II - 1800 - 200 feet per minute.
TYPE III and IV - 2000 - 200 feet per minute.