View Full Version : Parking with flaps extended
23rd Jul 2007, 12:30
Hello folks, a little question out of curiosity.
On Saturday I happened to notice several Citations parked on the Business Aviation apron at EDI, and one thing I spotted was that they were all parked with flaps extended. Also, I happened to be browsing through some Piper Tomahawk pictures on an aviation site when I noticed that several were parked again with their flaps extended.
This intrigued me, since at my club we always park with flaps up, and this also seems to be the norm on all Boeings and Scarebuses too.
Any particular reason why some aircraft are parked with flap down? :confused:
A and C
23rd Jul 2007, 12:37
Can't comment on the biz jets but the PA38 and DR400 it is common practice to park with flaps down to stop people standing on the flap when entering and exiting the aircraft.
23rd Jul 2007, 13:37
On the scarebus it is normal to leave the slats extended when the temperature reaches in excess of 30 degrees (no hope of that in EDI this year :\ ).
The reason being that the sensors that detect a wing bleed leak can get confused by the temp if the slats are shut and don't get any cooling air flow. Therefore it avoids nuisance ecam warnings in the cockpit.
23rd Jul 2007, 18:10
It is standard practice for certain series of Citations to be parked with partial flaps to prevent strain on the flaps systems. It has been a long time since I flew a Citation, however, I'm sure there is a Citation pilot here that can explain the reason better than I.
Is that Slats thingy in FCOM somewhere?
23rd Jul 2007, 19:03
Look in FCOM 3 under SOP after landing.
23rd Jul 2007, 19:07
On A300 we park with slats extended.
Reason, less wear cause we take off 99% slats only.
23rd Jul 2007, 19:55
Hetfield, we used to do the same on long runways(BAH) but use 15/15 now.In fact I cannot think of anywhere we do this,but we do put them away at night!
Many years ago we had an aircraft damaged taxi-ing in on a contaminated surface across in the US.It damaged the flap mechanism.However somewhere during the telephone call to engineering this translated into slats!!The engineers turned up with a big spanner for the slats and the rest as they say is history!!
24th Jul 2007, 00:15
For 500 series citations (and others i am sure) walkarounds must be done with the flaps partially extended. I think there is a sight glass that cannot be seen with the flaps up.
24th Jul 2007, 04:38
I have never had any bleed leak warnings and always select flaps 0 for parking, we did however have a fuel truck hit one of our 321's recently and damage the trailing edge, aircraft was parked in Config 1. :ugh:
24th Jul 2007, 06:12
Thanks for the replies folks.
25th Jul 2007, 01:43
3 or 4 years ago on the minibuses it was fairly common to get spurious but locked in ecam message of wing air bleed leak at >+30 c with slats up.
However most aircraft have since had this software glitch mod'ed out so its ok to leave the slats/flaps up in high temperatures now.
26th Jul 2007, 12:47
On the CRJ 100/200 we leave the flaps at 20 after landing, unless it's the last flight of the day then we bring them up. This reduces wear/tear on the flap drive system/FECU as well as allows us to check an AD that requires us to check and examine the position of the flaps before every takeoff.
26th Jul 2007, 14:56
The main problem I see with parking with the flaps extended is that it allows the actuation compontents to be exposed. The exposed compontents could be contaminated by moisture and dirt.
26th Jul 2007, 15:25
Yeah, for night stops and when no flight crew on board we retract them as well.
26th Jul 2007, 19:56
I seem to remember from years ago that the flaps on the HS 125 would droop after being parked for some time, simply because there was no hydraulic pressure.
27th Jul 2007, 03:21
On early model 500 series the flaps were cable drive. Because of this they were only to be left up when in flight or else the cables stretched.
27th Jul 2007, 16:47
Most (maybe all? ) of the airliners have hydraulic flap system, so after been parked for a while with no hyd pressure, they start to drop.
27th Jul 2007, 16:49
they start to drop.
27th Jul 2007, 19:01
there are only 2 perfrctly good reasons for parking an aircraft with the flaps extended.
one - fatique as happend to us lately
two - hijack, for god's sake they didn't mistake us for it those days
if the maufacturer require it - somethings really wrong!!!
Three --- real major problem!!!
31st Jul 2007, 08:58
Correct, the 500/550/560 have cable systems in the flaps, the flaps are either electrically or hydraulicly (S550, Ultra, Encore, Excel) driven. There will be some tension on the cables in the system if the flaps are in any position other than the takeoff position (or the 15 degree position for aircraft with 2 intermediate positions) so they are most frequently left in this position to prolong the life of the cables. Leaving the flaps slightly extended also allows for more coprehensive walkaround checks.
Most checklists do not however invite you to extend the flaps before the walk around due to considerations of battery duration (electric) or the fact you'd need to start an engine (hydraulic)
The flaps are actuated by a hydraulic motor attached to a jack-screw. Whatever position they are in when the pressure is taken away they will remain in.
The inboard gear doors may however drop down as the pressure deminishes if the aircraft is allowed to stand for a longer period of time.
Leaving the flaps down on the HS is daft as you'll increase the chance of corroding the actuator jack-screw or damage resulting from towing etc.