Landing Lights use on A320 family
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Landing Lights use on A320 family
Hi guys, i'd like to know your opinion about some changes in the sop of many airline with a320/a319. Many airlines don't use landing lights below FL100 but they retract just after take off at gear up ( i think ezy retracts after flap up) and during approach they extrat ldg lt after gear down. They told me they changed this part of sop due to fuel saving. Do you think there is a real and important fuel saving by changing this sop ?
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I don't know on the bus but the 737 MEL says that you can dispatch with a retract. light stuck out taking into account you will burn 1% more of the TOTAL planned trip fuel
Don't have any figures for the fuel saving, I-WEBA. As you know, presumably, the turn-off lights and taxi lights are only available when the nose gear is extended, and the wing-root-mounted landing lights can create a rumble. Below 250kts, the rumble may not be a problem, but the fuel penalty may still be measurable.
Conspicuity to other aircraft and birds must take priority over fuel economy, but circumstances vary on the day. In Europe, unless rules have changed since I retired, it is quite normal for ATC to permit speeds greater than 250kts below FL100, but lights are not mandatory. In the US, lights are mandatory below 10,000ft, but the 250kts speed limit also applies.
When I started my A320 conversion in 1988 - just before the aircraft gained type-certification - I was astonished to find that there was no flush-mounted forward-facing lighting. The A300 and A310 both had flush-mounted turn-off lights, like the vast majority of other jet airliners. (The only flush-mounted lighting on the A320 family are the wing-ice inspection lights, which only provide side conspicuity.)
PS
Now occurs to me that there may be some guidance in the MEL/DDM (Minimum Equipment List or Despatch Deviation Manual). Any stated fuel penalty from that source is likely to be an overestimate, however, for safety reasons. Also, it may be based on one or two units being stuck down.
Conspicuity to other aircraft and birds must take priority over fuel economy, but circumstances vary on the day. In Europe, unless rules have changed since I retired, it is quite normal for ATC to permit speeds greater than 250kts below FL100, but lights are not mandatory. In the US, lights are mandatory below 10,000ft, but the 250kts speed limit also applies.
When I started my A320 conversion in 1988 - just before the aircraft gained type-certification - I was astonished to find that there was no flush-mounted forward-facing lighting. The A300 and A310 both had flush-mounted turn-off lights, like the vast majority of other jet airliners. (The only flush-mounted lighting on the A320 family are the wing-ice inspection lights, which only provide side conspicuity.)
PS
Now occurs to me that there may be some guidance in the MEL/DDM (Minimum Equipment List or Despatch Deviation Manual). Any stated fuel penalty from that source is likely to be an overestimate, however, for safety reasons. Also, it may be based on one or two units being stuck down.
Last edited by Chris Scott; 12th Mar 2011 at 14:22. Reason: PS added
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Fokker (RIP) writes the following (valid for F70/100):
'Retracting the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 3 kg per take-off.'
and:
'Extending the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 2 kg per descent.'
'Retracting the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 3 kg per take-off.'
and:
'Extending the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 2 kg per descent.'
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Any fule saving natural reserve saving should be considered, any kind of drag will dafinately increse fule consumtion.
Probability of bird strike as you climb up reduces manifold, we have TCAS these dayes as an trfic awareness antycolition device.
Probability of bird strike as you climb up reduces manifold, we have TCAS these dayes as an trfic awareness antycolition device.
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In my previous company we used to retract the landing lights if high speed climb/descent was approved by the ATC.
The Airbus MEL clearly states the penalties for extended lights, but I am sure the 1% per light includes the entire enroute time including normal cruise. So 1% may not apply from gear retraction to 10,000' or from 10,000' to gear extension, like some airlines mentioned above are doing.
The Airbus MEL clearly states the penalties for extended lights, but I am sure the 1% per light includes the entire enroute time including normal cruise. So 1% may not apply from gear retraction to 10,000' or from 10,000' to gear extension, like some airlines mentioned above are doing.
Quote from DesiPilot:
I am sure the 1% per light includes the entire enroute time including normal cruise. So 1% may not apply from gear retraction to 10,000' or from 10,000' to gear extension, like some airlines mentioned above are doing.
You have a point. Presumably, the 1% per extended light is intended to be added to the calculated burn-off for the whole sector. Two lights would require a 2% increase. If lights are only to be extended below 10,000ft, the 2% penalty could be applied to the calculated burn below 10,000ft in the climb and descent. But the percentage increase in drag may be greater at higher IAS. (If it is TAS dependent, the cruise penalty would be higher.)
However, as I said at the end of my previous post, the percentage fuel penalty stated in the MEL has to err on the safe side, so may be an overestimate. The conveniently-neat figure of 1% per unit may have resulted from a lower figure being rounded up to cover what is, after all, a rare unserviceability.
I am sure the 1% per light includes the entire enroute time including normal cruise. So 1% may not apply from gear retraction to 10,000' or from 10,000' to gear extension, like some airlines mentioned above are doing.
You have a point. Presumably, the 1% per extended light is intended to be added to the calculated burn-off for the whole sector. Two lights would require a 2% increase. If lights are only to be extended below 10,000ft, the 2% penalty could be applied to the calculated burn below 10,000ft in the climb and descent. But the percentage increase in drag may be greater at higher IAS. (If it is TAS dependent, the cruise penalty would be higher.)
However, as I said at the end of my previous post, the percentage fuel penalty stated in the MEL has to err on the safe side, so may be an overestimate. The conveniently-neat figure of 1% per unit may have resulted from a lower figure being rounded up to cover what is, after all, a rare unserviceability.
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Fokker (RIP) writes the following (valid for F70/100):
'Retracting the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 3 kg per take-off.'
and:
'Extending the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 2 kg per descent.'
'Retracting the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 3 kg per take-off.'
and:
'Extending the landing lights at 5,000 ft in lieu of 10,000 ft would typically save 2 kg per descent.'
Where did you get this data? It's worth considering if there's a reasonable explanation to back up the above figures. Thanks
Where did you get this data?
https://simpleflying.com/aer-lingus-...anding-lights/
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Unlike many other aircraft, the current A320 does not have any lights in fixed positions on the outside of the aircraft. The runway turnoff lights are connected to the nose gear, and the landing lights are retractable. With gear up the only lights you can display are the landing lights, but they vibrate and yes, will increase the fuel burn slightly. So we switch them off at flap retraction.
They come on at gear down for the same reason.
This is also why A320 pilots will not «greet» other aircraft at cruise by flashing the lights.
Airbus have just annonuced a new design of the lights on the A320. All lights will be located in the wing root, taxi, turnoff and landing lights. Looks cool, but no mini speed brakes with this design.
They come on at gear down for the same reason.
This is also why A320 pilots will not «greet» other aircraft at cruise by flashing the lights.
Airbus have just annonuced a new design of the lights on the A320. All lights will be located in the wing root, taxi, turnoff and landing lights. Looks cool, but no mini speed brakes with this design.
The new A321XLR has them in the wing root. Fancy LED lumps they are too.
