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Manicured garden
29th Jul 2015, 11:28
Hello guys, just a quick question;

as I see on MEL/33.14 (B-737) exterior emergency exit lights may be INOP during day operations without any restriction. It doesn't say anything about night ops. Does that mean on night ops, INOP emergency exterior lights NO-GO?

One commander told me so and I was curious about that. Could you please enlighten me?

And about that question; for the cases like that not included in MEL, does that ALWAYS mean it's NO-GO item?

thanks in advance.

dixi188
29th Jul 2015, 11:53
Basically if an item is not listed in the MEL then it is required for flight.
If it is listed then any allowances will be shown.
There is a lot of information in the introduction of an MEL that many people fail to read.

In this case common sense would require external emergency lights at night but not in daylight. I expect the internal ones are required at all times as the cabin could be darkened by closed blinds.

Just a thought though. What if a solar eclipse is going to happen during your flight.

Skyjob
29th Jul 2015, 12:03
Minimum Equipment List, MEL, is just that: the MINIMUM EQUIPMENT LIST.

It lists those variations which can be accommodated in case of failed items or parts of them, anything not listed is a NO-GO, unless it can be placed under a generic heading.

In case of B737 MEL 33-14 Exterior Emergency Lighting System, it reads:
a) May be inoperative for day operations.
b) A single exit light may be inoperative for night operations, provided the provisions of MEL 52-16 are applied to the affected exit.

The referred to item 52-16. Emergency Exits (including Passenger Entry Doors, Galley Service Doors and Overwing Exits excluding flight Deck Emergency Exits) reads in turn:
(M) (O) One Exit may be inoperative provided
a) It is not reasonably practicable to repair the inoperative exit before the commencment of the fight.
b) Not more than 72 hours have elapsed since the exit became inoperative.
c) The aircraft does not exceed five (5) further flights with the exit inoperative.
d) The procedures detailed in DDPG 52-16 are followed.

DDPG 52-16 refers to "The exit unservicable placard must be affixed to the inoperative exit prior to passenger embarkation.", thus
MAINTENANCE (M)
1. The exit must be latched closed and not used for any purpose, and all associated exit / and or emergency exit markings , signs, and lights must be obscured.
2. The strip floor lighting at the exit must be masked.
3. All other exits and escape slides must be fully operative.
4. Tapes or ropes of conspicuous colours shall be installed to block access to unusable seats prior to bording of passengers.
OPERATIONS (O)
1. Persons (other than assigned cabin attendants) are not permitted to be seated in the blocked area.
2. The pre-take-off briefing to passengers must accurately represent the current state and condition of the aircraft’s escape facilities. An oral briefing by cabin staff, or a breifing using audio/visual means or a breifing by reference to a briefing card, must be immediately qualified by an oral announcement to draw the attention of passengers to the fact that a particular exit is inoperative and displays a exit unservicable placard.
3. Where the evacuation drill calls for cabin crew to be seated by the inoperative exit, they are breifed to direct passengers to a servicable exit.
4. Passenger reductions and seating configurations shall not deviate from those detailed in Figures 52-16 (a) to (d) on the following pages. These seating diagrams shall cover the following circumstances:
- Aft Door or Slide inoperative (LH or RH). [63/189 pax maximum]
- Forward Door or Slide inoperative (LH or RH). [63/189 pax maximum]
- Fwd Overwing Exit inoperative. [144/189 pax maximum]
- Aft Overwing Exit inoperative. [108/189 pax maximum]
5. The Adjusted Weights Loadsheet remains valid under the conditions of ...
6. The affected emergency exit and blocked seating layout are checked before each flight by the relevant cabin crew member.
7. The escape path to the affected emergency exit is checked by the relevant cabin crew member to be unobstructed before each takeoff and landing.


So in conclusion, you CAN depart at night with ONE exterior Emergency Exit light unserviceable provided the AFFECTED EXIT is NOT used for operational reasons, this may require reducing pax numbers as per YOUR DDPG, the mentioned numbers are for a 189 seat configuration.

vapilot2004
29th Jul 2015, 12:58
Does that mean on night ops, INOP emergency exterior lights NO-GO?

Yes. Anything not on the MEL is required to be present and operating for approved flight.

Manicured garden
3rd Aug 2015, 22:28
Thank you all guys...

RAT 5
4th Aug 2015, 10:22
So in conclusion, you CAN depart at night with ONE exterior Emergency Exit light unserviceable provided the AFFECTED EXIT is NOT used for operational reasons, this may require reducing pax numbers as per YOUR DDPG, the mentioned numbers are for a 189 seat configuration.

Just a discussion point guys, and a request for opinions. These kind of rules cause me to question the thinking behind them. I can go along with the idea that the exit may be considered unavailable at the 'planning' stage. We use this philosophy in other areas. However, at the actual moment of an evacuation the exit is perfectly serviceable. There is a strong school of thought that the 90sec evacuation time via 1/2 the exits with no hand luggage is unrealistic. So here is a useable exit, which may be on the good side (e.g. engine/brake fire or collapsed gear on the other side) and the C/A's are told it MUST NOT be used. Meanwhile pax are trapped inside the a/c and perhaps even some perish. That might lead to an interesting court case.
Imagine applying the same logic to an emergency escape exit from a building that catches fire. It would not happen. All exits are used even jumping out of windows. I'm not suggesting that on a/c, but not to use a serviceable door because of a light seems to be not the clearest of thinking and a rule devised behind a desk in a committee room.

Opinions, especially from any C/A's. What would you do with a cabin fire and seated next to an operative door?