Current Issues

The Air-conditioning Mod.
A pervasive rumor going around is that the floor ducting was taken out as part of the mod
and that this is going to lead to no heat from the baseboards and cold airplanes in the
wintertime. "NOT TRUE," says Ross Peterson, who is in charge of the Mod. 
The following summary gives the real scoop on the Air Conditioning Mod:
It's important to realize that there are three distinctly different air distribution
Configurations present in our fleet of Dash 8's. They can be divided up as follows:
                       (Pre-1990 Interior, pre-mod)
                       (Pre-1990 Interior, post-mod)
 	           (Post-1990 and Hunting Interior)
Each configuration required its own tailor-made modification to improve airflow.
Generally speaking, though, dirty filters were cleaned and modified, lines were enlarged and
insulated, and hot air pick-up points were eliminated. In addition, a significant amount of work
was performed to insulate all ductwork, as well as insulate the overhead frame structure to
prevent condensation from forming and dripping into the interior.
These are dramatic steps taken to keep the passengers and crews comfortable. 
In addition, if flight crews take the following steps during periods of hot weather, it will
allow the system to operate at peak efficiency:
  Operation in MANUAL FULL COLD is still not recommended. It can/will damage the
Air Cycle Machine and Condenser/Mixer, and stop all airflow from the Environmental
Control System.
  Keep Passenger Service Unit (PSU) lights off as much as practicable. These generate a
lot of radiant heat.
  Keep Overhead fluorescent lights and Sidewall lights off as much as practicable. Their
power supplies generate a lot of heat.
*  Use the UPPER DUCT position of the Duct Selector on the Flight Attendant's Panel.
  During turn-arounds, keep the airstair door closed as much as practicable. This limits the
amount of hot, humid air that enters the recirculated air supply.
   If practicable, turn off the cabin gaspers during a turn-around. This gets more return air to the air
Conditioning pack and lowers the duct temp.


Finally, if system performance is degraded, it is imperative that crews provide detailed
information to maintenance, such as;
  Duct temperature
 OAT
  Location where airflow is low (Cabin or Cockpit)
   If air conditioning works better with APU Bleed or Engine Bleed

Power Lever Stickers.
I suppose that everyone has noticed the stickers that warn us not to bring the power
levers below the flight idle stop in flight. The Airworthiness Directive that mandates this is a
direct result of the crash of the EMB-120 in Georgia that resulted in the death of Senator
Tower. The sticker is merely an interim fix. The manufacturer has two years to develop and
install a system that will prevent pilots from selecting below flight idle while in flight.
Actually, the Dash 8 is last in line on this, as this procedure has already been done to all of the
other transport category turboprops.

Bleeds Off Caution.
Look in the abnormal checklist on panel I IB. A note is repeated several times that
states that, "de-ice pressure may be insufficient with the bleeds off; avoid icing conditions." I
had always wondered about the logic behind that. As we all know, the tap-off for 18 psi de-ice
air is prior to the nacelle shut-off valves, so selecting the bleeds "off' should not affect boot
inflation.
Further research showed, however, that the caution is valid. On aircraft that do not
incorporate Mod 8/1375 (which includes our fleet of Dash 8's), turning off both bleeds also
takes away the ability to bring in HP bleed air. With only LP air available, de-ice pressure at
low power settings may not be sufficient to run the boots. Once again, the caution does apply to
all of our aircraft.