Page:CAB Accident Report, American Airlines Flight 383.pdf/15

– 14 – approach profile, such as pattern distances, airspeeds, descent rates, flap and landing gear sequencing, would depend upon the specific operational situation encountered at a particular airport on a given day. It was further stated that regardless of the deviations from the basic pattern it is always recommended that the conditions for a stabilized approach be established when the aircraft is on final approach, and that upon entering the "slot" the aircraft should be in the final landing configuration, and that only small adjustments to the glide path, approach speed, and trim should be performed.

It is also recommended in the operating manual that pilots utilize the ILS glide slope or visual approach slope indicator (VASI), if available, during VFR approaches as an aid in establishing and maintaining the proper approach flightpath.

AA Altimeter Procedures

Three Kollsman drum-pointer type altimeters were installed in N1996. This type altimeter has a range of from plus 50,000 feet to minus 1,500 feet. Hundreds of feet are indicated by a radial pointer; thousands of feet are indicated on a rotating drum visible through a slot in the face of this instrument. A cross-hatched marking is printed on the drum adjacent to the number from plus 1,000 feet to minus 1,500 feet to increase the conspicuity of these lower altitude values. (See Attachment #4.)

A conventional barometric scale (in inches or mercury) is provided for setting the altimeter. The scale is adjusted by a knob in the lower left corner of the altimeter. The knob also positions an index on the periphery of the instrument face which is used for setting field pressure altitude (QFE). The procedures for setting altimeters, as applicable in this case, are set forth in the AA Flight Manual as follows:

"(3) Descent Approach:

"(a) Aircraft descending through FL 180 (15,000' in Mexico) shall have the No. 1 and 2 altimeters change to appropriate QNH settings. Once again, all three altimeters will be set to the same setting and the No. 1 altimeter becomes the master.

"(b) When making "in range" or "changoverchangeover [sic]" report, both the No. 1 and the No. 2 altimeters shall be set to local station pressure (QFE) setting. The third altimeter shall continue to be set to the local station QNH setting.  After the No. 1 and 2 altimeters have been reset to the QFE setting, ATC specified altitudes will be maintained by reference to the third altimeter.

"(c) After setting the three altimeters per (b) above, the following check for accuracy shall be made by the Captain and First Officer. Subtract the altitude