B737-200 Gasper Fan operation.

[Centaurus]

My understanding is the Gasper Fan on the B737-200 was designed for use on the ground with one pack operation in hot weather. In other words to increase the already low airflow and make it slightly colder. Despite this I notice that some operators leave the gasper fan on until 10,000 ft in climb and switch it on at 10,000 ft in the descent. There is ample airflow coming through both packs when the aircraft is airborne and there is nothing to be gained by switching on the Gasper fan. Request thoughts on the matter because I think switching it on while airborne is a waste of time.

With the last and I believe final amendment by Boeing to the 737-200 FCTM, there is no mention of double engine failure approach and landing technique - yet one operator has published a full page in the QRH on flap settings, glide path angles etc required for a dead stick landing. One wonders if this QRH non-normal is Boeing authorised - or is it simply a company derived page published without measured data but as someone's personal view on how it should be done? Similar critical information on dead stick landings does not appear in either the Classics or NG latest QRH from Boeing.

[murykken]

Centaurus:
Having spent 18 years on B737-200, here is my take on the use of the Gasper Fan - basically it is used too much.

I ran it on the ground if it was hot, to increase the feel of the cooling air from the pack. If it was winter outside, why run the Gasper? All you are doing is increasing the flow of cold air. Remember where the source is for the gasper air. ASFKAP states it - from the cold air side of the pack.

I think the constant use of the gasper comes from its use in the sim - we are always needing a blast of air to cool us down! Perhaps that just gets carried over to the line, without thinking.

Having sat in the back, and watched passengers use the gasper outlets, I can testify that unless it is really warm in the cabin, most people feel the hard blast of cold air is too much, and close the vent, thereby negating what you are doing by running the fan. Remember, the system is not a recirculation system, a la DC-8. It is intended to increase the feel of the cold air.

Yes, it can be run continuosly, but why, if passengers close the outlet?

[Centaurus]

ASFKAP - thanks for the extract from the maintenance manual - it is certainly more comprehensive than Vol. 2. Also thanks Murykken for your reply. Basically it boils down to crews understanding the reason for the Gasper fan. But once an operator had published a "procedure" in the company Ops Manual based upon the writer's personal viewpoint rather than cold hard technical facts, then next we know it becomes a God authorised "procedure" and everyone duly falls into line. Then, in the words of the immortal "Yes Minister" TV series, it takes a courageous decision for a minion to stick his head above the rampart and say "Oy Boss!..this is all crap."