A B737-800's Wing Body Overheat light illuminated after takeoff due to an engine bleed switch being left on during a rushed departure procedure. An emergency was declared and flight diverted to a nearby airport for an overweight landing.
Synopsis
A B737-800's Wing Body Overheat light illuminated after takeoff due to an engine bleed switch being left on during a rushed departure procedure. An emergency was declared and flight diverted to a nearby airport for an overweight landing.
Narrative
As pilot flying; on initial climb out; the 'Master Caution' right '6-pack' and left 'Wing/Body Overheat' lights illuminated. Captain declared the emergency and we entered a radar-vector box pattern with TRACON. While accomplishing the QRH; the left engine bleed switch was found in the 'On' position. Captain accomplished the full QRH procedure. The overheat light remained on for a substantial amount of time after the QRH procedures were done; so in lieu of continuing we diverted to a nearby airport because we were above maximum landing weight and the departure airport's short runway. Captain declared the emergency for the overheat light and the overweight landing. Landing was as uneventful as possible. The overheat light did eventually extinguish; but interestingly came back on later while parked at the gate with the engines shut down and all left engine pack/bleed switches 'Off.' After maintenance action the aircraft was returned to service and we departed for our original destination. The overheat light was not on prior to or first departure but there were other issues; such as an inoperative APU. The light was on and off during the second flight. While a typical kind-of-day; this morning at our original airport was 'more typical' than others; the ground crew struggled to get the airplane to the gate with all the first wave and aircraft juggling from overnight parking to now empty gates. Naturally it was a 'critical flight' with the jet finally getting to the gate 40 minutes prior to departure and all the managers and helpers under the gun to get the flight out on time (or actually in time less 5 minutes). There were multiple MEL items that compounded upon one another in starting the airplane. 'APU Inop;' start the left engine at the gate cross-bleed start with Ground Control and then the Wing Body issue. After starting both; accomplishment of the before-taxi and mechanical checklists appeared to be normal. In retrospect we missed the left engine bleed switch being in the improper position. Rushing is a more insidious challenge to confront; and one that leads us to miss an important action. Observation: the placard above the Captain's PFD/ND is almost invisible to the First Officer. Additionally its three places removed from the true MEL issue. The MEL seeks to isolate the ducting from the bleed air (no anti-ice; bleed off; isolation valve closed; and air conditioning pack off). As a consequence of all that; the airplane is limited to FL250. The real issue is the lack of temperature protection; which the placard only addresses somewhat circuitously. Change the MEL in this instance to put an INOP sticker on the Wing/Body OVHT light in the air conditioning pack in addition to the one on the Captain's panel (Wing/Body OVHT INOP; maximum altitude FL250).
Second reporter narrative
I would have never thought that I could have been involved in an incident involving rushing or distractions of this nature that would have culminated in a procedural oversight while conduction procedures and checklist while on the ground. I recognize that I'm an average guy on my good days and I can be my own worst enemy. Corrective Actions/Recommendations: 1) Be reasonable expeditious (when appropriate) but never allow yourself to be rushed and make mistakes. 2) Don't allow distractions to permeate into the cockpit and influence cockpit and aircraft operations. 3) A placard was placed just above the Captain PFD to indicate the flight was limited to FL250. In addition; it would be appropriate (in my opinion) to have a placard located next to Wing Body Overheat light. Thus; when the Captain looks up at the Air Conditioning and Pressurization panel to confirm and respond to the mechanical checklist challenge; the placard would be a last minute reminder. 4) One additional item concerning the mechanical checklist challenge and response; it might be worth considering changing the response to the mechanical checklist challenge to state how the pack and bleed switches are configured vice 'checked.'
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.