Date: 201910
Location: ZZZ.Airport, US
Aircraft: B757 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Other N/A
Aircraft component: Air Conditioning and Pressurization Pack
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Other Training
Result: General None Reported / Taken
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: The following caution is listed twice in the B757-767 Flight Manual: Packs can be damaged if they are operated while preconditioned air is connected. The two locations are Initial Preflight Procedures and Supplementary Procedures.Based on my very limited experience of [X] months on the line as a ZZZ B757-767 First Officer; it is apparent that this caution is completely disregarded. I believe three things cause this: pilot training (initial and recurrent) doesn't address it and the pilots are not aware the caution exists; lack of training and procedural guidance for ground crews who connect air to the aircraft and/or are qualified to run the packs; it is inadequately addressed in the Flight Manual. This existence of this caution is relatively unknown to the B756 pilots I've discussed it with. I do not recall it being brought up in B756 training at [Company]. As it is a 'Caution'; it should be taught in academics. Most pilots do not ensure the preconditioned air is disconnected prior to turning on the packs; and most believe there is nothing wrong with doing so. This caution is very often not complied with by ground personnel. In my experience; it is a common occurrence to show up to the cockpit to fly and find that the pre-conditioned are is attached and blowing; and the aircraft packs are also running. I have had ground crews connect the air while I was in the cockpit and already running the packs. It appears there is a lack of knowledge with Maintenance/Ground Crew about the fact this can cause damage to equipment. Having spoken to ground personnel about it; it seems to be 'not a big deal' or 'no; it won't hurt anything'. It appears there are no company procedures (e.g. there is no SOP) in place for the Ground Crew to check to ensure the packs are off before connecting pre-conditioned air to the aircraft. If there are procedures; they are not being followed. Posting this caution in the Establishing Air Conditioning section (found within the Electrical section) is rather illogical; not intuitive and won't be easily found by a pilot looking for information about air systems or air conditioning. If a pilot is going to look in the Flight Manual for information about the packs and pre-conditioned air; I would expect they would look in Air Systems; or Engines; APU. Maybe in Hot Weather Operation. Nowhere in these relevant sections is this caution addressed. Since this is a limitation on how we may operate the aircraft; I would expect to see this caution in the Limitations section. There is even an Air Systems Limitations in section. Looks like a great place to have this caution posted! Can it be moved there? While we are at it; let's put the entire Establishing Air Conditioning section there; since its current location in Electrical makes no sense. The lack of concern about this caution begs the question 'Is this caution still relevant?' Or was something changed on the B757 that will allow the packs to be running and the preconditioned to be connected and won't 'result in damage to equipment if not carefully followed.' We either need to train and adhere to SOP's to follow the Flight Manual's guidance; or we need to remove the guidance if it is not relevant. But the current situation is not satisfactory... especially if there is a potential to damage equipment.




Synopsis: B757-767 First Officer reported that initial and recurrent training does not cover operation of the air-conditioning packs with pre-cooled air being supplied to the aircraft.